后端开发

后端开发的步骤：

• 根据需求,分析数据库建库、建表、准备数据（主键类型应是包装类,bigint）
• 建立web模块web类型的maven项目
• 手动创建src、resources、test-java目录
• 建立package、entity、dao、service、controller
• pom依赖，web模块依赖，webmvc,jackson依赖
• entity实体类
• dao接口,增加自定义的复杂关联查询(注解)
• service接口注入dao,调用相应方法
• 对service做单元测试（junit）
• controller,使用RESTful风格请求，完成控制层
• 对controller进行测试（使用postman,get查，put修改，post插，delete删）VO(试图对象)

新建一个模块web

• image.png

依赖

• pom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>
        <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-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，主要使用其中的JPA和事务-->
        <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>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-test</artifactId>
            <version>${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>${junit.version}</version>
            <scope>test</scope>
        </dependency>
        <!-- log4j日志依赖 -->
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>${log4j.version}</version>
        </dependency>
        <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>
        <!--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>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>servlet-api</artifactId>
            <version>2.5</version>
        </dependency>
    </dependencies>

    <build>
        <finalName>web</finalName>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>${project.build.sourceEncoding}</encoding>
                </configuration>
            </plugin>
            <!-- war插件 -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-war-plugin</artifactId>
                <version>2.1.1</version>
                <configuration>
                    <warName>web</warName>
                </configuration>
            </plugin>
        </plugins>
        <!-- 加载资源 -->
        <resources>
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>
    </build>
</project>

• web依赖

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
         http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">
    <display-name>web</display-name>
    <welcome-file-list>
        <welcome-file>index.html</welcome-file>
    </welcome-file-list>

    <!-- web容器配置，当tomcat启动，加载 web.xml配置文件 -->
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>

    <!-- 加载spring容器 ，当服务器启动，加载spring_mybatis.xml配置文件-->
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath:Spring-mybatis.xml</param-value>
    </context-param>

    <!-- 过滤器统一编码 -->
    <filter>
        <filter-name>Spring character encoding</filter-name>
        <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
        <init-param><!-- 过滤请求字符集 -->
            <param-name>encoding</param-name>
            <param-value>UTF-8</param-value>
        </init-param>
        <init-param><!-- 过滤响应字符集 -->
            <param-name>forceEncoding</param-name>
            <param-value>true</param-value>
        </init-param>
    </filter>
    <filter-mapping>
        <filter-name>Spring character encoding</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

    <!-- 控制器配置，当tomcat启动，加载springMVC-servlet.xml配置 -->
    <servlet>
        <servlet-name>springMVC</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springMvc-servlet.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <!-- mvc控制器映射 -->
    <servlet-mapping>
        <servlet-name>springMVC</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

    <!-- CORS Filter -->
    <filter>
        <filter-name>CORSFilter</filter-name>
        <filter-class>com.spring.web.util.CORSFilter</filter-class>
    </filter>
    <filter-mapping>
        <filter-name>CORSFilter</filter-name>
        <url-pattern>/*</url-pattern>
    </filter-mapping>

</web-app>

• springMVC-servlet

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:mvc="http://www.springframework.org/schema/mvc"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd
       http://www.springframework.org/schema/mvc
       http://www.springframework.org/schema/mvc/spring-mvc.xsd
       http://www.springframework.org/schema/context
       http://www.springframework.org/schema/context/spring-context.xsd">
    <!--启动mvc注解-->
    <mvc:annotation-driven/>
    <!--扫描含有注解的包 （控制器所在包）-->
    <context:component-scan base-package="com.spring.web.controller"/>
    <!--保证静态资源不被拦截-->
    <mvc:default-servlet-handler/>
</beans>

• Spring-mybatis

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:aop="http://www.springframework.org/schema/aop"
       xmlns:tx="http://www.springframework.org/schema/tx" xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
       http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

    <!--读入外部数据库连接属性文件-->
    <context:property-placeholder location="classpath:jdbc.properties"/>

    <!--扫描Service包的组件-->
    <context:component-scan base-package="com.spring.web.service"/>

    <!--通过druid配置数据源-->
    <bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"
          init-method="init" destroy-method="close">
        <property name="driverClassName" value="${jdbc.driverClassName}"/>
        <property name="url" value="${jdbc.url}"/>
        <property name="username" value="${jdbc.username}"/>
        <property name="password" value="${jdbc.password}"/>
        <!-- 初始化大小 -->
        <property name="initialSize" value="20"/>
        <!-- 连接池最大使用连接数量 -->
        <property name="maxActive" value="20"/>
        <!-- 连接池最小空闲 -->
        <property name="minIdle" value="0"/>
        <!-- 配置获取连接等待超时的时间 -->
        <property name="maxWait" value="60000"/>
        <!-- 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒 -->
        <property name="timeBetweenEvictionRunsMillis" value="60000"/>
        <!-- 配置一个连接在池中最小生存的时间，单位是毫秒 -->
        <property name="minEvictableIdleTimeMillis" value="300000"/>
        <!-- 连接空闲时测试是否有效 -->
        <property name="testWhileIdle" value="false"/>
        <!-- 获取连接时测试是否有效 -->
        <property name="testOnBorrow" value="false"/>
        <!-- 归还连接时是否测试有效 -->
        <property name="testOnReturn" value="false"/>
        <!-- 打开PSCache缓存，并且指定每个连接上PSCache的大小 -->
        <property name="poolPreparedStatements" value="true"/>
        <property name="maxPoolPreparedStatementPerConnectionSize" value="20"/>
    </bean>

    <!-- 配置mybatis的Session -->
    <bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="dataSource" ref="dataSource"/>
        <property name="typeAliasesPackage" value="com.spring.web.entity"/>
    </bean>

    <!-- 配置通用Mapper -->
    <bean class="tk.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="basePackage" value="com.spring.web.dao"/>
        <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
        <property name="markerInterface" value="com.spring.web.dao.BaseDAO"/>
        <property name="properties">
            <value>
                mappers = com.spring.web.dao.BaseDAO
                IDENTITY = MYSQL
            </value>
        </property>
    </bean>

    <!--事务管理bean -->
    <bean id="manager"
          class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
        <property name="dataSource" ref="dataSource"/>
    </bean>
    <!-- 使用声明式事务 -->
    <tx:annotation-driven transaction-manager="manager"/>
</beans>

建立Course,CourseVO,SysUser类

• 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;
}

• CourseVO类

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;
}

• 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;
}

建立BaseDAO,CourseDAO,SysUserDAo接口

• BaseDAO接口

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> {
}

• CourseDAO接口

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`")
    List<CourseVO> selectCurrentCourses();
}

• SysUserDAO接口

package com.spring.web.dao;

import com.spring.web.entity.SysUser;

public interface SysUserDAO extends BaseDAO<SysUser> {
}

Service类

• CourseService类

package com.spring.web.service;

import com.spring.web.entity.CourseVO;

import java.util.List;

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

• CourseService实现类

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.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.util.List;

@Service
@Transactional
public class CourseServiceImpl implements CourseService {
    @Autowired
    private CourseDAO courseDAO;

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

对CourseServiceImpl进行测试

• CourseServiceImplTest类

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));
    }
}

controller包

• CourseController类

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;
    }
}

• 对controller进行测试
  测试结果

  
  
  image.png

util包

• CORSFilter

package com.spring.web.util;

import javax.servlet.*;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class CORSFilter implements Filter{

    @Override
    public void init(FilterConfig filterConfig) throws ServletException {

    }

    @Override
    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
        System.out.println("work");
        HttpServletResponse response = (HttpServletResponse) servletResponse;
        response.setHeader("Access-Control-Allow-Origin", "*");
        response.setHeader("Access-Control-Allow-Methods", "POST, GET");
        response.setHeader("Access-Control-Max-Age", "3600");
        response.setHeader("Access-Control-Allow-Headers", "Content-Type, Access-Control-Allow-Headers, Authorization, X-Requested-With");
        filterChain.doFilter(servletRequest, servletResponse);
    }

    @Override
    public void destroy() {

    }
}

• ResponseUtil

package com.spring.web.util;

public class ResponseUtil {
    private int code;
    private String message;
    private Object data;


    public ResponseUtil(int code, String message) {
        this.code = code;
        this.message = message;
    }

    public ResponseUtil(int code, String message, Object data) {
        this.code = code;
        this.message = message;
        this.data = data;
    }

    @Override
    public String toString() {
        return "ResponseUtil{" +
                "code=" + code +
                ", message='" + message + '\'' +
                ", data=" + data +
                '}';
    }
}

前端开发

-新建一个html文件

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8" />
        <title>Vue.js-访问API接口数据-蓝墨云班课练习</title>
        <meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1,user-scalable=no">
        <meta http-equiv="X-UA-Compatible" content="ie=edge">
        <!-- 通过CDN引入Vue.js -->
        <script src="https://cdn.jsdelivr.net/npm/vue/dist/vue.js"></script>
        <!-- 通过CDN引入axios -->
        <script src="https://unpkg.com/axios/dist/axios.min.js"></script>
        <style type="text/css">
            body {
                background-color: #eee;
            }
            .top {
                width: 80%;
                margin: 0 auto;
                display: flex;
                justify-content: space-between;
            }
            hr{
                width: 80%;
                color: #efefef;
            }
            .container {
                width: 80%;
                margin: 0 auto;
                display: flex;
                flex-wrap: wrap;
                padding-left: 20px;
                padding-top: 10px;
            }
            .card {
                width: 215px;
                height: 330px;
                display: flex;
                flex-direction: column;
                border: 1px solid #eee;
                margin-right: 25px;
                margin-bottom: 10px;
                background-color: #fff;
                justify-content: center;
                padding-left: 5px;
                padding-right: 5px;
                padding-top: 5px;
            }
            .cover {
                width: 95%;
                height: 75%;
                margin-left: 7px;
                overflow: hidden;
            }
            .cover img{
                width: 100%;
                transition: all 5s;
            }
            .cover img:hover{
                transform: scaleX(1.1);
            }
            p {
                font-size: 12px;
                margin-bottom: 5px;
            }
            .teacher {
                display: flex;
                justify-content: space-between;
            }
            .left {
                display: flex;
            }
            .avatar img {
                width: 30px;
                height: 30px;
                border-radius: 50%;
                margin-right: 5px;
            }
            .code {
                color: #00BBDD;
                margin-top: 5px;
            }
            .card1{
                width: 215px;
                height: 330px;
                display: flex;
                flex-direction: column;
                border: 1px solid #eee;
                margin-right: 25px;
                margin-bottom: 10px;
                background-color: #fff;
                justify-content: center;
                padding-left: 5px;
                padding-right: 5px;
                padding-top: 5px;
                -webkit-filter: grayscale(100%);
                filter: grayscale(100%);
            }
        </style>
    </head>
    <body>
        <div id="app">
            <div class="top">
                <p>进行中的班课</p>
                <p>{{count}}个进行中的班课</p>
            </div>
            <hr>
            <div class="container">
                <div class="card" v-show="iffinished===course.finished" v-for="(course, index) in courses" :key="index">
                    <div class="cover">
                        <img :src="'img/'+course.cover">
                    </div>
                    <div class="course-class">
                        <p>{{course.courseClass}}</p>
                    </div>
                    <div class="course-name">
                        <p>{{course.courseName}}</p>
                    </div>
                    <div class="teacher">
                        <div class="left">
                            <div class="avatar">
                                <img :src="'img/'+course.avatar">
                            </div>
                            <div class="username">
                                <p class="code">{{course.username}}</p>
                            </div>
                        </div>
                        <div class="course-code">
                            <p class="code" v-if="loginUserId === course.userId">{{course.courseCode}}</p>
                        </div>
                    </div>
                </div>

            </div>
            
            <div class="top">
                <p>已结束的班课的班课</p>
                <p>{{courses.length-count}}个已结束的班课</p>
            </div>
            <hr>
            <div class="container">
                <div class="card1" v-show="iffinished!==course.finished" v-for="(course, index) in courses" :key="index">
                    <div class="cover">
                        <img :src="'img/'+course.cover">
                    </div>
                    <div class="course-class">
                        <p>{{course.courseClass}}</p>
                    </div>
                    <div class="course-name">
                        <p>{{course.courseName}}</p>
                    </div>
                    <div class="teacher">
                        <div class="left">
                            <div class="avatar">
                                <img :src="'img/'+course.avatar">
                            </div>
                            <div class="username">
                                <p class="code">{{course.username}}</p>
                            </div>
                        </div>
                        <div class="course-code">
                            <p class="code" v-if="loginUserId === course.userId">{{course.courseCode}}</p>
                        </div>
                    </div>
                </div>
            
            </div>
        </div>
        <script type="text/javascript">
            var app = new Vue({
                el: '#app',
                data: {
                    iffinished:0,
                    loginUserId: 1,
                    courses: []
                },
                created: function() {
                    var _this = this;
                    axios.get('http://192.168.43.194:8080/web/courses')
                        .then(function(response) {
                            console.log(response.data);
                            _this.courses = response.data;
                        })
                },
                computed:{
                    count:function(){
                    var clength=this.courses.length;
                    var num=0;
                    for(var i=0;i<clength;i++){
                        if(this.iffinished===this.courses[i].finished){
                            num++
                        }
                    }
                    return num;
                    }
                    
                }
            })
        </script>
    </body>
</html>

结果

image.png