四、《任务列表案例》后端程序实现和测试

本章概要

• 准备工作
• 功能实现
• 前后联调

4.1 准备工作

1. 数据库脚本

CREATE TABLE schedule (
  id INT NOT NULL AUTO_INCREMENT,
  title VARCHAR(255) NOT NULL,
  completed BOOLEAN NOT NULL,
  PRIMARY KEY (id)
);

INSERT INTO schedule (title, completed)
VALUES
    ('学习java', true),
    ('学习Python', false),
    ('学习C++', true),
    ('学习JavaScript', false),
    ('学习HTML5', true),
    ('学习CSS3', false),
    ('学习Vue.js', true),
    ('学习React', false),
    ('学习Angular', true),
    ('学习Node.js', false),
    ('学习Express', true),
    ('学习Koa', false),
    ('学习MongoDB', true),
    ('学习MySQL', false),
    ('学习Redis', true),
    ('学习Git', false),
    ('学习Docker', true),
    ('学习Kubernetes', false),
    ('学习AWS', true),
    ('学习Azure', false);

2. 准备 pojo

包：com.atguigu.pojo

/**
 * projectName: com.atguigu.pojo
 *
 * description: 任务实体类
 */
@Data
public class Schedule {

    private Integer id;
    private String title;
    private Boolean completed;
}

3. 准备 R

包： com.atguigu.utils

**
 * projectName: com.atguigu.utils
 *
 * description: 返回结果类
 */
public class R {

    private int code = 200; //200成功状态码

    private boolean flag = true; //返回状态

    private Object data;  //返回具体数据


    public  static R ok(Object data){
        R r = new R();
        r.data = data;
        return r;
    }

    public static R  fail(Object data){
        R r = new R();
        r.code = 500; //错误码
        r.flag = false; //错误状态
        r.data = data;
        return r;
    }


    public int getCode() {
        return code;
    }

    public void setCode(int code) {
        this.code = code;
    }

    public boolean isFlag() {
        return flag;
    }

    public void setFlag(boolean flag) {
        this.flag = flag;
    }

    public Object getData() {
        return data;
    }

    public void setData(Object data) {
        this.data = data;
    }
}

4. 准备 PageBean

包： com.atguigu.utils

@Data
@NoArgsConstructor
@AllArgsConstructor
public class PageBean<T> {
    private int currentPage;   // 当前页码
    private int pageSize;      // 每页显示的数据量
    private long total;    // 总数据条数
    private List<T> data;      // 当前页的数据集合
}

4.2 功能实现

1. 分页查询

• controller

/*
    @CrossOrigin 注释在带注释的控制器方法上启用跨源请求
 */
@CrossOrigin
@RequestMapping("schedule")
@RestController
public class ScheduleController
{

    @Autowired
    private ScheduleService scheduleService;

    @GetMapping("/{pageSize}/{currentPage}")
    public R showList(@PathVariable(name = "pageSize") int pageSize, @PathVariable(name = "currentPage") int currentPage){
        PageBean<Schedule> pageBean = scheduleService.findByPage(pageSize,currentPage);
        return  R.ok(pageBean);
    }
}

• service

@Slf4j
@Service
public class ScheduleServiceImpl  implements ScheduleService {

    @Autowired
    private ScheduleMapper scheduleMapper;

    /**
     * 分页数据查询,返回分页pageBean
     *
     * @param pageSize
     * @param currentPage
     * @return
     */
    @Override
    public PageBean<Schedule> findByPage(int pageSize, int currentPage) {
        //1.设置分页参数
        PageHelper.startPage(currentPage,pageSize);
        //2.数据库查询
        List<Schedule> list = scheduleMapper.queryPage();
        //3.结果获取
        PageInfo<Schedule> pageInfo = new PageInfo<>(list);
        //4.pageBean封装
        PageBean<Schedule> pageBean = new PageBean<>(pageInfo.getPageNum(),pageInfo.getPageSize(),pageInfo.getTotal(),pageInfo.getList());

        log.info("分页查询结果:{}",pageBean);

        return pageBean;
    }

}

• mapper

mapper 接口

public interface ScheduleMapper {

    List<Schedule> queryPage();
}    

mapper.xml 文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
        "https://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!-- namespace等于mapper接口类的全限定名,这样实现对应 -->
<mapper namespace="com.atguigu.mapper.ScheduleMapper">

    <select id="queryPage" resultType="schedule">
        select * from schedule
    </select>
</mapper>    

2. 计划添加

• controller

@PostMapping
public R saveSchedule(@RequestBody Schedule schedule){
    scheduleService.saveSchedule(schedule);
    return R.ok(null);
}

• service

/**
 * 保存学习计划
 *
 * @param schedule
 */
@Override
public void saveSchedule(Schedule schedule) {
    scheduleMapper.insert(schedule);
}

• mapper

mapper 接口

void insert(Schedule schedule);

mapper.xml 文件

<insert id="insert">
    insert into schedule (title, completed)
    values
    (#{title}, #{completed});
</insert>

3. 计划删除

• controller

@DeleteMapping("/{id}")
public R removeSchedule(@PathVariable Integer id){
    scheduleService.removeById(id);
    return R.ok(null);
}

• service

/**
 * 移除学习计划
 *
 * @param id
 */
@Override
public void removeById(Integer id) {
    scheduleMapper.delete(id);
}

• mapper

mapper 接口

void delete(Integer id);

mapper.xml 文件

<delete id="delete">
    delete from schedule where id = #{id}
</delete>

4. 计划修改

• controller

@PutMapping
    public R changeSchedule(@RequestBody Schedule schedule){
    scheduleService.updateSchedule(schedule);
    return R.ok(null);
}

• service

/**
 * 更新学习计划
 *
 * @param schedule
 */
@Override
public void updateSchedule(Schedule schedule) {
    scheduleMapper.update(schedule);
}

• mapper

mapper 接口

void update(Schedule schedule);

mapper.xml 文件

<update id="update">
    update schedule set title = #{title} , completed = #{completed}
         where id = #{id}
</update>

4.3 前后联调

1. 后台项目根路径设计

2. 启动测试即可