（译）Spring Boot + Spring Security + JWT + MySQL + React Full Stack Polling app - Part 3

原文链接: https://www.callicoder.com/spring-boot-spring-security-jwt-mysql-react-app-part-3/

欢迎来到全栈开发系列第三章（Spring Boot，Spring Security，JWT，MySQL，React）。

在本文中，我们将构建以下REST API：创建调查，投票，获取用户资料等。

在Github上查看该项目的完整源代码。

spring-boot-spring-security-jwt-mysql-full-stack-polling-app.jpg

在写API之前，我们需要先创建Poll，Choice和Vote的实体。
我们希望在Poll模型中包括谁发起了这项投票，并将当前登录的用户自动填充到Poll实体中。

创建Auditing模型

为了完成自动填充创建人功能，我们需要定义一个审查模型UserDateAudit继承自DateAudit。
他包含createdBy和updatedBy字段。

UserDateAudit

在com.exmaple.polls.model.audit包下创建UserDateAudit类

package com.example.polls.model.audit;

import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import org.springframework.data.annotation.CreatedBy;
import org.springframework.data.annotation.LastModifiedBy;

import javax.persistence.Column;
import javax.persistence.MappedSuperclass;

@MappedSuperclass
@JsonIgnoreProperties(
        value = {"createdBy", "updatedBy"},
        allowGetters = true
)
public abstract class UserDateAudit extends DateAudit {
    @CreatedBy
    @Column(updatable = false)
    private Long createdBy;

    @LastModifiedBy
    private Long updatedBy;

    public Long getCreatedBy() {
        return createdBy;
    }

    public void setCreatedBy(Long createdBy) {
        this.createdBy = createdBy;
    }

    public Long getUpdatedBy() {
        return updatedBy;
    }

    public void setUpdatedBy(Long updatedBy) {
        this.updatedBy = updatedBy;
    }
}

配置Auditing

现在，为了能实现自动填充createdBy和updatedBy字段，我们需要对AuditingConfig做以下修改。

package com.example.polls.config;

import com.example.polls.security.UserPrincipal;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.data.domain.AuditorAware;
import org.springframework.data.jpa.repository.config.EnableJpaAuditing;
import org.springframework.security.authentication.AnonymousAuthenticationToken;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.context.SecurityContextHolder;
import java.util.Optional;

@Configuration
@EnableJpaAuditing
public class AuditingConfig {

    @Bean
    public AuditorAware<Long> auditorProvider() {
        return new SpringSecurityAuditAwareImpl();
    }
}

class SpringSecurityAuditAwareImpl implements AuditorAware<Long> {

    @Override
    public Optional<Long> getCurrentAuditor() {
        Authentication authentication = SecurityContextHolder.getContext().getAuthentication();

        if (authentication == null ||
                !authentication.isAuthenticated() ||
                authentication instanceof AnonymousAuthenticationToken) {
            return Optional.empty();
        }

        UserPrincipal userPrincipal = (UserPrincipal) authentication.getPrincipal();
        
        return Optional.ofNullable(userPrincipal.getId());
    }
}

业务模型

1.Vote类（发起一项民意调查的实体）

Poll实体应由id，question，若干个choices和expirationDateTime字段组成。以下是完整的Poll类。

package com.example.polls.model;

import com.example.polls.model.audit.UserDateAudit;
import org.hibernate.annotations.BatchSize;
import org.hibernate.annotations.Fetch;
import org.hibernate.annotations.FetchMode;
import javax.persistence.*;
import javax.validation.constraints.NotBlank;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
import java.time.Instant;
import java.util.ArrayList;
import java.util.List;

@Entity
@Table(name = "polls")
public class Poll extends UserDateAudit {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @NotBlank
    @Size(max = 140)
    private String question;

    @OneToMany(
            mappedBy = "poll",
            cascade = CascadeType.ALL,
            fetch = FetchType.EAGER,
            orphanRemoval = true
    )
    @Size(min = 2, max = 6)
    @Fetch(FetchMode.SELECT)
    @BatchSize(size = 30)
    private List<Choice> choices = new ArrayList<>();

    @NotNull
    private Instant expirationDateTime;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getQuestion() {
        return question;
    }

    public void setQuestion(String question) {
        this.question = question;
    }

    public List<Choice> getChoices() {
        return choices;
    }

    public void setChoices(List<Choice> choices) {
        this.choices = choices;
    }

    public Instant getExpirationDateTime() {
        return expirationDateTime;
    }

    public void setExpirationDateTime(Instant expirationDateTime) {
        this.expirationDateTime = expirationDateTime;
    }

    public void addChoice(Choice choice) {
        choices.add(choice);
        choice.setPoll(this);
    }

    public void removeChoice(Choice choice) {
        choices.remove(choice);
        choice.setPoll(null);
    }
}

2. Choice类（投票的选择项）

每一个Choice对象应有一个id，text，还有一个与Poll关联的外键。以下是Choice完整的代码。

package com.example.polls.model;

import javax.persistence.*;
import javax.validation.constraints.NotBlank;
import javax.validation.constraints.Size;
import java.util.Objects;

@Entity
@Table(name = "choices")
public class Choice {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @NotBlank
    @Size(max = 40)
    private String text;

    @ManyToOne(fetch = FetchType.LAZY, optional = false)
    @JoinColumn(name = "poll_id", nullable = false)
    private Poll poll;

    public Choice() {

    }

    public Choice(String text) {
        this.text = text;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getText() {
        return text;
    }

    public void setText(String text) {
        this.text = text;
    }

    public Poll getPoll() {
        return poll;
    }

    public void setPoll(Poll poll) {
        this.poll = poll;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Choice choice = (Choice) o;
        return Objects.equals(id, choice.id);
    }

    @Override
    public int hashCode() {
        return Objects.hash(id);
    }
}

3.Vote类（投票）

Vote类包含了用户在哪个Poll中投了哪个Choice。以下就是完整的Vote代码。

package com.example.polls.model;

import com.example.polls.model.audit.DateAudit;
import javax.persistence.*;

@Entity
@Table(name = "votes", uniqueConstraints = {
        @UniqueConstraint(columnNames = {
                "poll_id",
                "user_id"
        })
})
public class Vote extends DateAudit {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @ManyToOne(fetch = FetchType.LAZY, optional = false)
    @JoinColumn(name = "poll_id", nullable = false)
    private Poll poll;

    @ManyToOne(fetch = FetchType.LAZY, optional = false)
    @JoinColumn(name = "choice_id", nullable = false)
    private Choice choice;

    @ManyToOne(fetch = FetchType.LAZY, optional = false)
    @JoinColumn(name = "user_id", nullable = false)
    private User user;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public Poll getPoll() {
        return poll;
    }

    public void setPoll(Poll poll) {
        this.poll = poll;
    }

    public Choice getChoice() {
        return choice;
    }

    public void setChoice(Choice choice) {
        this.choice = choice;
    }

    public User getUser() {
        return user;
    }

    public void setUser(User user) {
        this.user = user;
    }
}

Repositoies

让我们为这些类定义数据仓库，从数据库中获取数据。

1. PollRepository

package com.example.polls.repository;

import com.example.polls.model.Poll;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.stereotype.Repository;
import java.util.List;
import java.util.Optional;

@Repository
public interface PollRepository extends JpaRepository<Poll, Long> {
    Optional<Poll> findById(Long pollId);

    Page<Poll> findByCreatedBy(Long userId, Pageable pageable);

    long countByCreatedBy(Long userId);

    List<Poll> findByIdIn(List<Long> pollIds);

    List<Poll> findByIdIn(List<Long> pollIds, Sort sort);
}

2. VoteRepository

package com.example.polls.repository;

import com.example.polls.model.ChoiceVoteCount;
import com.example.polls.model.Vote;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.query.Param;
import org.springframework.stereotype.Repository;
import java.util.List;

@Repository
public interface VoteRepository extends JpaRepository<Vote, Long> {
    @Query("SELECT NEW com.example.polls.model.ChoiceVoteCount(v.choice.id, count(v.id)) FROM Vote v WHERE v.poll.id in :pollIds GROUP BY v.choice.id")
    List<ChoiceVoteCount> countByPollIdInGroupByChoiceId(@Param("pollIds") List<Long> pollIds);

    @Query("SELECT NEW com.example.polls.model.ChoiceVoteCount(v.choice.id, count(v.id)) FROM Vote v WHERE v.poll.id = :pollId GROUP BY v.choice.id")
    List<ChoiceVoteCount> countByPollIdGroupByChoiceId(@Param("pollId") Long pollId);

    @Query("SELECT v FROM Vote v where v.user.id = :userId and v.poll.id in :pollIds")
    List<Vote> findByUserIdAndPollIdIn(@Param("userId") Long userId, @Param("pollIds") List<Long> pollIds);

    @Query("SELECT v FROM Vote v where v.user.id = :userId and v.poll.id = :pollId")
    Vote findByUserIdAndPollId(@Param("userId") Long userId, @Param("pollId") Long pollId);

    @Query("SELECT COUNT(v.id) from Vote v where v.user.id = :userId")
    long countByUserId(@Param("userId") Long userId);

    @Query("SELECT v.poll.id FROM Vote v WHERE v.user.id = :userId")
    Page<Long> findVotedPollIdsByUserId(@Param("userId") Long userId, Pageable pageable);
}

VoteRepository中有一些带着@Query注解的自定义查询，我使用自定义查询的原因是因为-

Spring Date JPA的动态生成查询无法满足所有查询
即使可以构建，也无法优化这些查询
于是，我们使用 JPQL constructor expression做一些查询，可以将结果返回到我们自定义的ChoiceVoteCount中。

ChoiceVoteCount

ChoiceVoteCount类就是我们用于在 VoteRepository中接收返回的自定义结果。

package com.example.polls.model;

public class ChoiceVoteCount {
    private Long choiceId;
    private Long voteCount;

    public ChoiceVoteCount(Long choiceId, Long voteCount) {
        this.choiceId = choiceId;
        this.voteCount = voteCount;
    }

    public Long getChoiceId() {
        return choiceId;
    }

    public void setChoiceId(Long choiceId) {
        this.choiceId = choiceId;
    }

    public Long getVoteCount() {
        return voteCount;
    }

    public void setVoteCount(Long voteCount) {
        this.voteCount = voteCount;
    }
}

构建Rest APIs

在构建API之前，我们需要定义各个API的入参体和返回体。

Request Payloads

1. PollRequest

package com.example.polls.payload;

import javax.validation.Valid;
import javax.validation.constraints.NotBlank;
import javax.validation.constraints.NotNull;
import javax.validation.constraints.Size;
import java.util.List;

public class PollRequest {
    @NotBlank
    @Size(max = 140)
    private String question;

    @NotNull
    @Size(min = 2, max = 6)
    @Valid
    private List<ChoiceRequest> choices;

    @NotNull
    @Valid
    private PollLength pollLength;

    public String getQuestion() {
        return question;
    }

    public void setQuestion(String question) {
        this.question = question;
    }

    public List<ChoiceRequest> getChoices() {
        return choices;
    }

    public void setChoices(List<ChoiceRequest> choices) {
        this.choices = choices;
    }

    public PollLength getPollLength() {
        return pollLength;
    }

    public void setPollLength(PollLength pollLength) {
        this.pollLength = pollLength;
    }
}

2.ChoiceRequest

package com.example.polls.payload;

import javax.validation.constraints.NotBlank;
import javax.validation.constraints.Size;

public class ChoiceRequest {
    @NotBlank
    @Size(max = 40)
    private String text;

    public String getText() {
        return text;
    }

    public void setText(String text) {
        this.text = text;
    }
}

3. PollLength

package com.example.polls.payload;

import javax.validation.constraints.Max;
import javax.validation.constraints.NotNull;

public class PollLength {
    @NotNull
    @Max(7)
    private Integer days;

    @NotNull
    @Max(23)
    private Integer hours;

    public int getDays() {
        return days;
    }

    public void setDays(int days) {
        this.days = days;
    }

    public int getHours() {
        return hours;
    }

    public void setHours(int hours) {
        this.hours = hours;
    }
}

4. VoteRequest

package com.example.polls.payload;
import javax.validation.constraints.NotNull;

public class VoteRequest {
    @NotNull
    private Long choiceId;

    public Long getChoiceId() {
        return choiceId;
    }

    public void setChoiceId(Long choiceId) {
        this.choiceId = choiceId;
    }
}

Response Payloads

1. UserSummary

package com.example.polls.payload;

public class UserSummary {
    private Long id;
    private String username;
    private String name;

    public UserSummary(Long id, String username, String name) {
        this.id = id;
        this.username = username;
        this.name = name;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

2. UserIdentityAvailability

package com.example.polls.payload;

public class UserIdentityAvailability {
    private Boolean available;

    public UserIdentityAvailability(Boolean available) {
        this.available = available;
    }

    public Boolean getAvailable() {
        return available;
    }

    public void setAvailable(Boolean available) {
        this.available = available;
    }
}

3. UserProfile

package com.example.polls.payload;

import java.time.Instant;

public class UserProfile {
    private Long id;
    private String username;
    private String name;
    private Instant joinedAt;
    private Long pollCount;
    private Long voteCount;

    public UserProfile(Long id, String username, String name, Instant joinedAt, Long pollCount, Long voteCount) {
        this.id = id;
        this.username = username;
        this.name = name;
        this.joinedAt = joinedAt;
        this.pollCount = pollCount;
        this.voteCount = voteCount;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Instant getJoinedAt() {
        return joinedAt;
    }

    public void setJoinedAt(Instant joinedAt) {
        this.joinedAt = joinedAt;
    }

    public Long getPollCount() {
        return pollCount;
    }

    public void setPollCount(Long pollCount) {
        this.pollCount = pollCount;
    }

    public Long getVoteCount() {
        return voteCount;
    }

    public void setVoteCount(Long voteCount) {
        this.voteCount = voteCount;
    }
}

4. PollResponse

package com.example.polls.payload;

import com.fasterxml.jackson.annotation.JsonInclude;

import java.time.Instant;
import java.util.List;

public class PollResponse {
    private Long id;
    private String question;
    private List<ChoiceResponse> choices;
    private UserSummary createdBy;
    private Instant creationDateTime;
    private Instant expirationDateTime;
    private Boolean isExpired;

    @JsonInclude(JsonInclude.Include.NON_NULL)
    private Long selectedChoice;
    private Long totalVotes;

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getQuestion() {
        return question;
    }

    public void setQuestion(String question) {
        this.question = question;
    }

    public List<ChoiceResponse> getChoices() {
        return choices;
    }

    public void setChoices(List<ChoiceResponse> choices) {
        this.choices = choices;
    }

    public UserSummary getCreatedBy() {
        return createdBy;
    }

    public void setCreatedBy(UserSummary createdBy) {
        this.createdBy = createdBy;
    }


    public Instant getCreationDateTime() {
        return creationDateTime;
    }

    public void setCreationDateTime(Instant creationDateTime) {
        this.creationDateTime = creationDateTime;
    }

    public Instant getExpirationDateTime() {
        return expirationDateTime;
    }

    public void setExpirationDateTime(Instant expirationDateTime) {
        this.expirationDateTime = expirationDateTime;
    }

    public Boolean getExpired() {
        return isExpired;
    }

    public void setExpired(Boolean expired) {
        isExpired = expired;
    }

    public Long getSelectedChoice() {
        return selectedChoice;
    }

    public void setSelectedChoice(Long selectedChoice) {
        this.selectedChoice = selectedChoice;
    }

    public Long getTotalVotes() {
        return totalVotes;
    }

    public void setTotalVotes(Long totalVotes) {
        this.totalVotes = totalVotes;
    }
}

5. ChoiceResponse

package com.example.polls.payload;

public class ChoiceResponse {
    private long id;
    private String text;
    private long voteCount;

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public String getText() {
        return text;
    }

    public void setText(String text) {
        this.text = text;
    }

    public long getVoteCount() {
        return voteCount;
    }

    public void setVoteCount(long voteCount) {
        this.voteCount = voteCount;
    }
}

6. PagedResponse

package com.example.polls.payload;

import java.util.List;

public class PagedResponse<T> {

    private List<T> content;
    private int page;
    private int size;
    private long totalElements;
    private int totalPages;
    private boolean last;

    public PagedResponse() {

    }

    public PagedResponse(List<T> content, int page, int size, long totalElements, int totalPages, boolean last) {
        this.content = content;
        this.page = page;
        this.size = size;
        this.totalElements = totalElements;
        this.totalPages = totalPages;
        this.last = last;
    }

    public List<T> getContent() {
        return content;
    }

    public void setContent(List<T> content) {
        this.content = content;
    }

    public int getPage() {
        return page;
    }

    public void setPage(int page) {
        this.page = page;
    }

    public int getSize() {
        return size;
    }

    public void setSize(int size) {
        this.size = size;
    }

    public long getTotalElements() {
        return totalElements;
    }

    public void setTotalElements(long totalElements) {
        this.totalElements = totalElements;
    }

    public int getTotalPages() {
        return totalPages;
    }

    public void setTotalPages(int totalPages) {
        this.totalPages = totalPages;
    }

    public boolean isLast() {
        return last;
    }

    public void setLast(boolean last) {
        this.last = last;
    }
}

工具类

除了请求体和返回体，我们的controllers和services还需要用到一些工具类。

1. AppConstants

package com.example.polls.util;

public interface AppConstants {
    String DEFAULT_PAGE_NUMBER = "0";
    String DEFAULT_PAGE_SIZE = "30";

    int MAX_PAGE_SIZE = 50;
}

2. ModelMapper

package com.example.polls.util;

import com.example.polls.model.Poll;
import com.example.polls.model.User;
import com.example.polls.payload.ChoiceResponse;
import com.example.polls.payload.PollResponse;
import com.example.polls.payload.UserSummary;

import java.time.Instant;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

public class ModelMapper {

    public static PollResponse mapPollToPollResponse(Poll poll, Map<Long, Long> choiceVotesMap, User creator, Long userVote) {
        PollResponse pollResponse = new PollResponse();
        pollResponse.setId(poll.getId());
        pollResponse.setQuestion(poll.getQuestion());
        pollResponse.setCreationDateTime(poll.getCreatedAt());
        pollResponse.setExpirationDateTime(poll.getExpirationDateTime());
        Instant now = Instant.now();
        pollResponse.setExpired(poll.getExpirationDateTime().isBefore(now));

        List<ChoiceResponse> choiceResponses = poll.getChoices().stream().map(choice -> {
            ChoiceResponse choiceResponse = new ChoiceResponse();
            choiceResponse.setId(choice.getId());
            choiceResponse.setText(choice.getText());

            if(choiceVotesMap.containsKey(choice.getId())) {
                choiceResponse.setVoteCount(choiceVotesMap.get(choice.getId()));
            } else {
                choiceResponse.setVoteCount(0);
            }
            return choiceResponse;
        }).collect(Collectors.toList());

        pollResponse.setChoices(choiceResponses);
        UserSummary creatorSummary = new UserSummary(creator.getId(), creator.getUsername(), creator.getName());
        pollResponse.setCreatedBy(creatorSummary);

        if(userVote != null) {
            pollResponse.setSelectedChoice(userVote);
        }

        long totalVotes = pollResponse.getChoices().stream().mapToLong(ChoiceResponse::getVoteCount).sum();
        pollResponse.setTotalVotes(totalVotes);

        return pollResponse;
    }
}

我们将Poll实体包装成PollResponse返回。他包含了创建调查的用户姓名，每个选项的投票数，当前用户投票的记录。这些信息都是前端需要的。

编写Rest API

我们可以controller里编写API了。

1. PollController

创建一项调查(Poll)
根据创建时间排序的调查列表
获取单个调查(Poll)
投票

PollController使用到了PollService去验证和处理一些请求。我们在下一节定义它。

package com.example.polls.controller;

import com.example.polls.model.*;
import com.example.polls.payload.*;
import com.example.polls.repository.PollRepository;
import com.example.polls.repository.UserRepository;
import com.example.polls.repository.VoteRepository;
import com.example.polls.security.CurrentUser;
import com.example.polls.security.UserPrincipal;
import com.example.polls.service.PollService;
import com.example.polls.util.AppConstants;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.ResponseEntity;
import org.springframework.security.access.prepost.PreAuthorize;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.servlet.support.ServletUriComponentsBuilder;
import javax.validation.Valid;
import java.net.URI;

@RestController
@RequestMapping("/api/polls")
public class PollController {

    @Autowired
    private PollRepository pollRepository;

    @Autowired
    private VoteRepository voteRepository;

    @Autowired
    private UserRepository userRepository;

    @Autowired
    private PollService pollService;

    private static final Logger logger = LoggerFactory.getLogger(PollController.class);

    @GetMapping
    public PagedResponse<PollResponse> getPolls(@CurrentUser UserPrincipal currentUser,
                                                @RequestParam(value = "page", defaultValue = AppConstants.DEFAULT_PAGE_NUMBER) int page,
                                                @RequestParam(value = "size", defaultValue = AppConstants.DEFAULT_PAGE_SIZE) int size) {
        return pollService.getAllPolls(currentUser, page, size);
    }

    @PostMapping
    @PreAuthorize("hasRole('USER')")
    public ResponseEntity<?> createPoll(@Valid @RequestBody PollRequest pollRequest) {
        Poll poll = pollService.createPoll(pollRequest);

        URI location = ServletUriComponentsBuilder
                .fromCurrentRequest().path("/{pollId}")
                .buildAndExpand(poll.getId()).toUri();

        return ResponseEntity.created(location)
                .body(new ApiResponse(true, "Poll Created Successfully"));
    }

    @GetMapping("/{pollId}")
    public PollResponse getPollById(@CurrentUser UserPrincipal currentUser,
                                    @PathVariable Long pollId) {
        return pollService.getPollById(pollId, currentUser);
    }

    @PostMapping("/{pollId}/votes")
    @PreAuthorize("hasRole('USER')")
    public PollResponse castVote(@CurrentUser UserPrincipal currentUser,
                         @PathVariable Long pollId,
                         @Valid @RequestBody VoteRequest voteRequest) {
        return pollService.castVoteAndGetUpdatedPoll(pollId, voteRequest, currentUser);
    }
}

2. UserController

在 UserController，我们将编写API来完成-

获取当前登录用户
检查用户名是否被注册
检查邮箱是否被注册
获取用户的公开资料
获取指定用户创建的调查列表
获取指定用户的投票的调查列表

package com.example.polls.controller;

import com.example.polls.exception.ResourceNotFoundException;
import com.example.polls.model.User;
import com.example.polls.payload.*;
import com.example.polls.repository.PollRepository;
import com.example.polls.repository.UserRepository;
import com.example.polls.repository.VoteRepository;
import com.example.polls.security.UserPrincipal;
import com.example.polls.service.PollService;
import com.example.polls.security.CurrentUser;
import com.example.polls.util.AppConstants;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.security.access.prepost.PreAuthorize;
import org.springframework.web.bind.annotation.*;

@RestController
@RequestMapping("/api")
public class UserController {

    @Autowired
    private UserRepository userRepository;

    @Autowired
    private PollRepository pollRepository;

    @Autowired
    private VoteRepository voteRepository;

    @Autowired
    private PollService pollService;

    private static final Logger logger = LoggerFactory.getLogger(UserController.class);

    @GetMapping("/user/me")
    @PreAuthorize("hasRole('USER')")
    public UserSummary getCurrentUser(@CurrentUser UserPrincipal currentUser) {
        UserSummary userSummary = new UserSummary(currentUser.getId(), currentUser.getUsername(), currentUser.getName());
        return userSummary;
    }

    @GetMapping("/user/checkUsernameAvailability")
    public UserIdentityAvailability checkUsernameAvailability(@RequestParam(value = "username") String username) {
        Boolean isAvailable = !userRepository.existsByUsername(username);
        return new UserIdentityAvailability(isAvailable);
    }

    @GetMapping("/user/checkEmailAvailability")
    public UserIdentityAvailability checkEmailAvailability(@RequestParam(value = "email") String email) {
        Boolean isAvailable = !userRepository.existsByEmail(email);
        return new UserIdentityAvailability(isAvailable);
    }

    @GetMapping("/users/{username}")
    public UserProfile getUserProfile(@PathVariable(value = "username") String username) {
        User user = userRepository.findByUsername(username)
                .orElseThrow(() -> new ResourceNotFoundException("User", "username", username));

        long pollCount = pollRepository.countByCreatedBy(user.getId());
        long voteCount = voteRepository.countByUserId(user.getId());

        UserProfile userProfile = new UserProfile(user.getId(), user.getUsername(), user.getName(), user.getCreatedAt(), pollCount, voteCount);

        return userProfile;
    }

    @GetMapping("/users/{username}/polls")
    public PagedResponse<PollResponse> getPollsCreatedBy(@PathVariable(value = "username") String username,
                                                         @CurrentUser UserPrincipal currentUser,
                                                         @RequestParam(value = "page", defaultValue = AppConstants.DEFAULT_PAGE_NUMBER) int page,
                                                         @RequestParam(value = "size", defaultValue = AppConstants.DEFAULT_PAGE_SIZE) int size) {
        return pollService.getPollsCreatedBy(username, currentUser, page, size);
    }


    @GetMapping("/users/{username}/votes")
    public PagedResponse<PollResponse> getPollsVotedBy(@PathVariable(value = "username") String username,
                                                       @CurrentUser UserPrincipal currentUser,
                                                       @RequestParam(value = "page", defaultValue = AppConstants.DEFAULT_PAGE_NUMBER) int page,
                                                       @RequestParam(value = "size", defaultValue = AppConstants.DEFAULT_PAGE_SIZE) int size) {
        return pollService.getPollsVotedBy(username, currentUser, page, size);
    }

}

PollService

PollController和UserController都使用到了PollService去获得PollResponse返回给客户端。

package com.example.polls.service;

import com.example.polls.exception.BadRequestException;
import com.example.polls.exception.ResourceNotFoundException;
import com.example.polls.model.*;
import com.example.polls.payload.PagedResponse;
import com.example.polls.payload.PollRequest;
import com.example.polls.payload.PollResponse;
import com.example.polls.payload.VoteRequest;
import com.example.polls.repository.PollRepository;
import com.example.polls.repository.UserRepository;
import com.example.polls.repository.VoteRepository;
import com.example.polls.security.UserPrincipal;
import com.example.polls.util.AppConstants;
import com.example.polls.util.ModelMapper;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.dao.DataIntegrityViolationException;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.stereotype.Service;
import java.time.Duration;
import java.time.Instant;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.function.Function;
import java.util.stream.Collectors;

@Service
public class PollService {

    @Autowired
    private PollRepository pollRepository;

    @Autowired
    private VoteRepository voteRepository;

    @Autowired
    private UserRepository userRepository;

    private static final Logger logger = LoggerFactory.getLogger(PollService.class);

    public PagedResponse<PollResponse> getAllPolls(UserPrincipal currentUser, int page, int size) {
        validatePageNumberAndSize(page, size);

        // Retrieve Polls
        Pageable pageable = PageRequest.of(page, size, Sort.Direction.DESC, "createdAt");
        Page<Poll> polls = pollRepository.findAll(pageable);

        if(polls.getNumberOfElements() == 0) {
            return new PagedResponse<>(Collections.emptyList(), polls.getNumber(),
                    polls.getSize(), polls.getTotalElements(), polls.getTotalPages(), polls.isLast());
        }

        // Map Polls to PollResponses containing vote counts and poll creator details
        List<Long> pollIds = polls.map(Poll::getId).getContent();
        Map<Long, Long> choiceVoteCountMap = getChoiceVoteCountMap(pollIds);
        Map<Long, Long> pollUserVoteMap = getPollUserVoteMap(currentUser, pollIds);
        Map<Long, User> creatorMap = getPollCreatorMap(polls.getContent());

        List<PollResponse> pollResponses = polls.map(poll -> {
            return ModelMapper.mapPollToPollResponse(poll,
                    choiceVoteCountMap,
                    creatorMap.get(poll.getCreatedBy()),
                    pollUserVoteMap == null ? null : pollUserVoteMap.getOrDefault(poll.getId(), null));
        }).getContent();

        return new PagedResponse<>(pollResponses, polls.getNumber(),
                polls.getSize(), polls.getTotalElements(), polls.getTotalPages(), polls.isLast());
    }

    public PagedResponse<PollResponse> getPollsCreatedBy(String username, UserPrincipal currentUser, int page, int size) {
        validatePageNumberAndSize(page, size);

        User user = userRepository.findByUsername(username)
                .orElseThrow(() -> new ResourceNotFoundException("User", "username", username));

        // Retrieve all polls created by the given username
        Pageable pageable = PageRequest.of(page, size, Sort.Direction.DESC, "createdAt");
        Page<Poll> polls = pollRepository.findByCreatedBy(user.getId(), pageable);

        if (polls.getNumberOfElements() == 0) {
            return new PagedResponse<>(Collections.emptyList(), polls.getNumber(),
                    polls.getSize(), polls.getTotalElements(), polls.getTotalPages(), polls.isLast());
        }

        // Map Polls to PollResponses containing vote counts and poll creator details
        List<Long> pollIds = polls.map(Poll::getId).getContent();
        Map<Long, Long> choiceVoteCountMap = getChoiceVoteCountMap(pollIds);
        Map<Long, Long> pollUserVoteMap = getPollUserVoteMap(currentUser, pollIds);

        List<PollResponse> pollResponses = polls.map(poll -> {
            return ModelMapper.mapPollToPollResponse(poll,
                    choiceVoteCountMap,
                    user,
                    pollUserVoteMap == null ? null : pollUserVoteMap.getOrDefault(poll.getId(), null));
        }).getContent();

        return new PagedResponse<>(pollResponses, polls.getNumber(),
                polls.getSize(), polls.getTotalElements(), polls.getTotalPages(), polls.isLast());
    }

    public PagedResponse<PollResponse> getPollsVotedBy(String username, UserPrincipal currentUser, int page, int size) {
        validatePageNumberAndSize(page, size);

        User user = userRepository.findByUsername(username)
                .orElseThrow(() -> new ResourceNotFoundException("User", "username", username));

        // Retrieve all pollIds in which the given username has voted
        Pageable pageable = PageRequest.of(page, size, Sort.Direction.DESC, "createdAt");
        Page<Long> userVotedPollIds = voteRepository.findVotedPollIdsByUserId(user.getId(), pageable);

        if (userVotedPollIds.getNumberOfElements() == 0) {
            return new PagedResponse<>(Collections.emptyList(), userVotedPollIds.getNumber(),
                    userVotedPollIds.getSize(), userVotedPollIds.getTotalElements(),
                    userVotedPollIds.getTotalPages(), userVotedPollIds.isLast());
        }

        // Retrieve all poll details from the voted pollIds.
        List<Long> pollIds = userVotedPollIds.getContent();

        Sort sort = Sort.by(Sort.Direction.DESC, "createdAt");
        List<Poll> polls = pollRepository.findByIdIn(pollIds, sort);

        // Map Polls to PollResponses containing vote counts and poll creator details
        Map<Long, Long> choiceVoteCountMap = getChoiceVoteCountMap(pollIds);
        Map<Long, Long> pollUserVoteMap = getPollUserVoteMap(currentUser, pollIds);
        Map<Long, User> creatorMap = getPollCreatorMap(polls);

        List<PollResponse> pollResponses = polls.stream().map(poll -> {
            return ModelMapper.mapPollToPollResponse(poll,
                    choiceVoteCountMap,
                    creatorMap.get(poll.getCreatedBy()),
                    pollUserVoteMap == null ? null : pollUserVoteMap.getOrDefault(poll.getId(), null));
        }).collect(Collectors.toList());

        return new PagedResponse<>(pollResponses, userVotedPollIds.getNumber(), userVotedPollIds.getSize(), userVotedPollIds.getTotalElements(), userVotedPollIds.getTotalPages(), userVotedPollIds.isLast());
    }


    public Poll createPoll(PollRequest pollRequest) {
        Poll poll = new Poll();
        poll.setQuestion(pollRequest.getQuestion());

        pollRequest.getChoices().forEach(choiceRequest -> {
            poll.addChoice(new Choice(choiceRequest.getText()));
        });

        Instant now = Instant.now();
        Instant expirationDateTime = now.plus(Duration.ofDays(pollRequest.getPollLength().getDays()))
                .plus(Duration.ofHours(pollRequest.getPollLength().getHours()));

        poll.setExpirationDateTime(expirationDateTime);

        return pollRepository.save(poll);
    }

    public PollResponse getPollById(Long pollId, UserPrincipal currentUser) {
        Poll poll = pollRepository.findById(pollId).orElseThrow(
                () -> new ResourceNotFoundException("Poll", "id", pollId));

        // Retrieve Vote Counts of every choice belonging to the current poll
        List<ChoiceVoteCount> votes = voteRepository.countByPollIdGroupByChoiceId(pollId);

        Map<Long, Long> choiceVotesMap = votes.stream()
                .collect(Collectors.toMap(ChoiceVoteCount::getChoiceId, ChoiceVoteCount::getVoteCount));

        // Retrieve poll creator details
        User creator = userRepository.findById(poll.getCreatedBy())
                .orElseThrow(() -> new ResourceNotFoundException("User", "id", poll.getCreatedBy()));

        // Retrieve vote done by logged in user
        Vote userVote = null;
        if(currentUser != null) {
            userVote = voteRepository.findByUserIdAndPollId(currentUser.getId(), pollId);
        }

        return ModelMapper.mapPollToPollResponse(poll, choiceVotesMap,
                creator, userVote != null ? userVote.getChoice().getId(): null);
    }

    public PollResponse castVoteAndGetUpdatedPoll(Long pollId, VoteRequest voteRequest, UserPrincipal currentUser) {
        Poll poll = pollRepository.findById(pollId)
                .orElseThrow(() -> new ResourceNotFoundException("Poll", "id", pollId));

        if(poll.getExpirationDateTime().isBefore(Instant.now())) {
            throw new BadRequestException("Sorry! This Poll has already expired");
        }

        User user = userRepository.getOne(currentUser.getId());

        Choice selectedChoice = poll.getChoices().stream()
                .filter(choice -> choice.getId().equals(voteRequest.getChoiceId()))
                .findFirst()
                .orElseThrow(() -> new ResourceNotFoundException("Choice", "id", voteRequest.getChoiceId()));

        Vote vote = new Vote();
        vote.setPoll(poll);
        vote.setUser(user);
        vote.setChoice(selectedChoice);

        try {
            vote = voteRepository.save(vote);
        } catch (DataIntegrityViolationException ex) {
            logger.info("User {} has already voted in Poll {}", currentUser.getId(), pollId);
            throw new BadRequestException("Sorry! You have already cast your vote in this poll");
        }

        //-- Vote Saved, Return the updated Poll Response now --

        // Retrieve Vote Counts of every choice belonging to the current poll
        List<ChoiceVoteCount> votes = voteRepository.countByPollIdGroupByChoiceId(pollId);

        Map<Long, Long> choiceVotesMap = votes.stream()
                .collect(Collectors.toMap(ChoiceVoteCount::getChoiceId, ChoiceVoteCount::getVoteCount));

        // Retrieve poll creator details
        User creator = userRepository.findById(poll.getCreatedBy())
                .orElseThrow(() -> new ResourceNotFoundException("User", "id", poll.getCreatedBy()));

        return ModelMapper.mapPollToPollResponse(poll, choiceVotesMap, creator, vote.getChoice().getId());
    }


    private void validatePageNumberAndSize(int page, int size) {
        if(page < 0) {
            throw new BadRequestException("Page number cannot be less than zero.");
        }

        if(size > AppConstants.MAX_PAGE_SIZE) {
            throw new BadRequestException("Page size must not be greater than " + AppConstants.MAX_PAGE_SIZE);
        }
    }

    private Map<Long, Long> getChoiceVoteCountMap(List<Long> pollIds) {
        // Retrieve Vote Counts of every Choice belonging to the given pollIds
        List<ChoiceVoteCount> votes = voteRepository.countByPollIdInGroupByChoiceId(pollIds);

        Map<Long, Long> choiceVotesMap = votes.stream()
                .collect(Collectors.toMap(ChoiceVoteCount::getChoiceId, ChoiceVoteCount::getVoteCount));

        return choiceVotesMap;
    }

    private Map<Long, Long> getPollUserVoteMap(UserPrincipal currentUser, List<Long> pollIds) {
        // Retrieve Votes done by the logged in user to the given pollIds
        Map<Long, Long> pollUserVoteMap = null;
        if(currentUser != null) {
            List<Vote> userVotes = voteRepository.findByUserIdAndPollIdIn(currentUser.getId(), pollIds);

            pollUserVoteMap = userVotes.stream()
                    .collect(Collectors.toMap(vote -> vote.getPoll().getId(), vote -> vote.getChoice().getId()));
        }
        return pollUserVoteMap;
    }

    Map<Long, User> getPollCreatorMap(List<Poll> polls) {
        // Get Poll Creator details of the given list of polls
        List<Long> creatorIds = polls.stream()
                .map(Poll::getCreatedBy)
                .distinct()
                .collect(Collectors.toList());

        List<User> creators = userRepository.findByIdIn(creatorIds);
        Map<Long, User> creatorMap = creators.stream()
                .collect(Collectors.toMap(User::getId, Function.identity()));

        return creatorMap;
    }
}

启动应用

你可以通过以下命令启动应用

mvn spring-boot:run

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