十一.前后端分离开发——后端

利用前后端Spring 和 View 前后端分离开发技术编写蓝慕云页面

1.根据需求，分析数据库、建库、建表、准备数据

(1) 创建 db_spring 数据库
(2) 建立 t_sys_user 表并添加数据

t_sys_user表.png

数据 t_sys_user 表.png

(3) 创建 t_course 表添加数据

t_course 表.png

数据 t_course 表.png

2.建立web模块

在 idea 中新建 webapp 类型的 maven 项目

webapp.png
分别手动建立 "src" "resources" "test-java" 文件夹
将 "src" 设置为 "Sources Root"
"resources" 设置为 "Resources Root"
"test" 设置为 "Test Sources Root"
(选中文件夹右击 ---> Mark Directory as --->)

目录设置.png
建立package : entity、dao、service、controller service-impl 如图所示层次：

package层次.png
在 pom.xml 中添加依赖(主要添加web模块依赖、webmvc模块依赖、jacksonmi模块依赖)

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com,spring</groupId>
  <artifactId>web</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>war</packaging>

  <name>web Maven Webapp</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.8</maven.compiler.source>
    <maven.compiler.target>1.8</maven.compiler.target>
    <spring.version>5.1.5.RELEASE</spring.version>
    <aspectj.version>1.9.2</aspectj.version>
    <junit.version>4.12</junit.version>
    <log4j.version>1.2.17</log4j.version>
    <slf4j.version>1.7.12</slf4j.version>
    <hutool.version>4.5.1</hutool.version>
    <mysql.version>5.1.47</mysql.version>
    <mybatis.version>3.5.0</mybatis.version>
    <mybatis-spring.version>2.0.0</mybatis-spring.version>
    <tk-mybatis.version>4.1.5</tk-mybatis.version>
    <druid.version>1.1.14</druid.version>
    <lombok.version>1.18.6</lombok.version>
    <jackson.version>2.9.8</jackson.version>
    <jackson-mapper.version>1.9.13</jackson-mapper.version>
  </properties>

  <dependencies>


    <!--spring-aop依赖-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-aop</artifactId>
      <version>${spring.version}</version>
    </dependency>
    <!--aspectj依赖-->
    <dependency>
      <groupId>org.aspectj</groupId>
      <artifactId>aspectjrt</artifactId>
      <version>${aspectj.version}</version>
    </dependency>
    <dependency>
      <groupId>org.aspectj</groupId>
      <artifactId>aspectjweaver</artifactId>
      <version>${aspectj.version}</version>
    </dependency>


    <!--hutool依赖-->
    <dependency>
      <groupId>cn.hutool</groupId>
      <artifactId>hutool-all</artifactId>
      <version>${hutool.version}</version>
    </dependency>

    <dependency>
      <groupId>com.google.zxing</groupId>
      <artifactId>core</artifactId>
      <version>3.3.3</version>
    </dependency>




    <!--Spring-context依赖-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-context</artifactId>
      <version>${spring.version}</version>
    </dependency>
    <!--spring-tx事务依赖-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-tx</artifactId>
      <version>${spring.version}</version>
    </dependency>
    <!--spring-jdbc依赖-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-jdbc</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <!--spring-web依赖-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-web</artifactId>
      <version>${spring.version}</version>
    </dependency>
    <!--spring-webmvc依赖-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-webmvc</artifactId>
      <version>${spring.version}</version>
    </dependency>



    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>servlet-api</artifactId>
      <version>3.0-alpha-1</version>
    </dependency>





    <!--spring-test依赖-->
    <dependency>
      <groupId>org.springframework</groupId>
      <artifactId>spring-test</artifactId>
      <version>${spring.version}</version>
    </dependency>

    <!--mysql依赖-->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>${mysql.version}</version>
    </dependency>

    <!--mybatis依赖-->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis</artifactId>
      <version>${mybatis.version}</version>
    </dependency>

    <!--mybatis-spring依赖-->
    <dependency>
      <groupId>org.mybatis</groupId>
      <artifactId>mybatis-spring</artifactId>
      <version>${mybatis-spring.version}</version>
    </dependency>

    <!--通用mapper依赖-->
    <dependency>
      <groupId>tk.mybatis</groupId>
      <artifactId>mapper</artifactId>
      <version>${tk-mybatis.version}</version>
    </dependency>

    <!--druid连接池依赖-->
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>druid</artifactId>
      <version>${druid.version}</version>
    </dependency>

    <!--Lombok 依赖-->
    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <version>${lombok.version}</version>
      <scope>provided</scope>
    </dependency>

    <!--junit依赖-->
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>${junit.version}</version>
      <scope>test</scope>
    </dependency>

    <!-- log4j日志依赖 -->
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-api</artifactId>
      <version>${slf4j.version}</version>
    </dependency>
    <dependency>
      <groupId>org.slf4j</groupId>
      <artifactId>slf4j-log4j12</artifactId>
      <version>${slf4j.version}</version>
    </dependency>
    <dependency>
      <groupId>log4j</groupId>
      <artifactId>log4j</artifactId>
      <version>${log4j.version}</version>
    </dependency>


    <!--jackson相关依赖-->
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-databind</artifactId>
      <version>${jackson.version}</version>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-core</artifactId>
      <version>${jackson.version}</version>
    </dependency>
    <dependency>
      <groupId>com.fasterxml.jackson.core</groupId>
      <artifactId>jackson-annotations</artifactId>
      <version>${jackson.version}</version>
    </dependency>
    <dependency>
      <groupId>org.codehaus.jackson</groupId>
      <artifactId>jackson-mapper-asl</artifactId>
      <version>${jackson-mapper.version}</version>
    </dependency>

  </dependencies>

  <build>
    <finalName>web</finalName>
    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.1.0</version>
        </plugin>
        <!-- see http://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_war_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-war-plugin</artifactId>
          <version>3.2.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>

3.编写代码

3.1 entity 实体类

(1) Course 类

package com.spring.web.entity;
import lombok.Data;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Table(name = "t_course")
@Data
public class Course {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long courseId;
    private String courseName;
    private Long userId;
    private String courseClass;
    private String cover;
    private String courseCode;
    private Short finished;
}

(2) SysUser 类

package com.spring.web.entity;

import lombok.Data;

import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Table(name = "t_sys_user")
@Data
public class SysUser {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long userId;
    private String mobile;
    private String password;
    private String username;
    private String avatar;
}

(3) CourseVO 类 ( VO：代表视图对象 )

package com.spring.web.entity;

import lombok.Data;

@Data
public class CourseVO {
    private Long courseId;
    private String courseName;
    private Long userId;
    private String courseClass;
    private String cover;
    private String courseCode;
    private Short finished;
    private String username;
    private String avatar;
}

3.2 DAO接口，增加自定义的复杂关联查询(注解)

(1) BaseDAO

package com.spring.web.dao;

import tk.mybatis.mapper.common.Mapper;
import tk.mybatis.mapper.common.MySqlMapper;

/**
 * 通用DAO接口
 */

public interface BaseDAO<T> extends Mapper<T>,MySqlMapper<T> {

}

(2) SysUserDAO

package com.spring.web.dao;

import com.spring.web.entity.SysUser;

public interface SysUserDAO extends BaseDAO<SysUser> {
}

(3) CourseDAO

package com.spring.web.dao;

import com.spring.web.entity.Course;
import com.spring.web.entity.CourseVO;
import org.apache.ibatis.annotations.Result;
import org.apache.ibatis.annotations.Results;
import org.apache.ibatis.annotations.Select;


import java.util.List;

public interface CourseDAO extends BaseDAO<Course>{

    //自定义的多表关联查询
    @Results({@Result(column = "course_id",property = "courseId"),
            @Result(column = "course_name",property = "courseName"),
            @Result(column = "user_id",property = "userId"),
            @Result(column = "course_class",property ="courseClass" ),
            @Result(column = "cover",property = "cover"),
            @Result(column = "course_code",property = "courseCode"),
            @Result(column = "finished",property = "finished"),
            @Result(column = "username",property = "username"),
            @Result(column = "avatar",property = "avatar")

    })
    @Select("SELECT a.*,b.username,b.avatar FROM t_course a Left JOIN t_sys_user b ON a.user_id=b.user_id WHERE a.finished = 0  ")
    //WHERE a.finished = 0 LIMIT 0,4
    List<CourseVO> selectCurrentCourses();
    @Results({@Result(column = "course_id",property = "courseId"),
            @Result(column = "course_name",property = "courseName"),
            @Result(column = "user_id",property = "userId"),
            @Result(column = "course_class",property ="courseClass" ),
            @Result(column = "cover",property = "cover"),
            @Result(column = "course_code",property = "courseCode"),
            @Result(column = "finished",property = "finished"),
            @Result(column = "username",property = "username"),
            @Result(column = "avatar",property = "avatar")

    })
    @Select("SELECT a.*,b.username,b.avatar FROM t_course a Left JOIN t_sys_user b ON a.user_id=b.user_id WHERE a.finished = 1  ")
        //WHERE a.finished = 0 LIMIT 0,4
    List<CourseVO> selectCurrentCourses1();



}

数据库中t_course表的finished属性：0代表班课正在进行中，1代表班课已结束；

selectCurrentCourses() 方法是获取所有正在进行中的蓝墨云班课

selectCurrentCourses1() 方法是获取所有已结束的蓝墨云班课

3.3 service接口，注入dao，调用相应方法

(1）CourseService

package com.spring.web.service;
import com.spring.web.entity.CourseVO;

import java.util.List;

public interface CourseService {
    List<CourseVO> selectCurrentCourses();
    List<CourseVO> selectCurrentCourses1();
}

(3) CourseServiceImpl


package com.spring.web.service.impl;

import com.spring.web.dao.CourseDAO;
import com.spring.web.entity.CourseVO;
import com.spring.web.service.CourseService;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;
import java.util.List;

@Service
@Transactional
public class CourseServiceImpl implements CourseService {

    @Resource
    private CourseDAO courseDAO;

    @Override
    public List<CourseVO> selectCurrentCourses() {

        return courseDAO.selectCurrentCourses();
    }

    @Override
    public List<CourseVO> selectCurrentCourses1() {
        return courseDAO.selectCurrentCourses1();

    }
}

3.4 对 CourseServiceImpl 进行单元测试

package com.spring.web.service.impl;

import com.spring.web.entity.CourseVO;
import com.spring.web.service.CourseService;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

import java.util.List;

import static org.junit.Assert.*;

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {"/spring_mybatis.xml"})
public class CourseServiceImplTest {


    @Autowired
    private CourseService courseService;
    @Test
    public void selectCurrentCourses() {
        List<CourseVO> courseVOList = courseService.selectCurrentCourses();
        courseVOList.forEach(courseVO -> System.out.println(courseVO));
    }
}

运行截图

运行结果.png

3.5 controller接口，使用RESTful风格请求

package com.spring.web.controller;

import com.spring.web.entity.CourseVO;


import com.spring.web.service.CourseService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
public class CourseController {
    @Autowired
    private CourseService courseService;


    @RequestMapping(value = "courses", method = RequestMethod.GET)
    public List<CourseVO> selectCourses() {
        List<CourseVO> courseVOList = courseService.selectCurrentCourses();
        return courseVOList;
    }

    @RequestMapping(value = "courses1", method = RequestMethod.GET)
    public List<CourseVO> selectCourses1() {
        List<CourseVO> courseVOList = courseService.selectCurrentCourses1();
        return courseVOList;
    }
}

4.用postman对Contraller进行测试，杜绝一切404和500(需启动 Tomcat)

结束班课信息.png

正在进行班课信息.png

POST：数据库增添数据
DELETE：数据库删除数据
PUT：数据库改变数据
GET：数据库查询数据

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十一.前后端分离开发——后端

1.根据需求，分析数据库、建库、建表、准备数据

2.建立web模块

3.编写代码

4.用postman对Contraller进行测试，杜绝一切404和500(需启动 Tomcat)

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