【SpringBoot】实现增删改查

目录结构

查询全部数据

controller

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  //注入mapper
  @Autowired
  private UserMapper userMapper;
  //查询数据
  @GetMapping
  public List<User> getUser(){
      List<User> userList = userMapper.findAll();
      return userList;
  }

mapper

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  @Select("SELECT * from sys_user")
  List<User> findAll();

增加数据

controller

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  //新增数据
  @PostMapping
  public Integer adduser(@RequestBody User user){
      System.out.println(user);
      return userMapper.insert(user);
  }

mapper

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  @Insert("INSERT into sys_user(username,password,nickname,email,phone) VALUES (#{username},#{password},#{nickname},#{email},#{phone})")
  int insert(User user);

修改数据

controller

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  //修改用户
  @PostMapping("/updateuser")
  public Integer updateuser(@RequestBody User user){
      return userMapper.update(user);
  }

mapper
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```
  int update(User user);
```
动态sql mapper
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> <mapper namespace="com.spring2.mapper.UserMapper"> <update id="update"> update sys_user <set> <if test="username != null"> username = #{username}, </if> <if test="password != null"> password = #{password}, </if> <if test="nickname != null"> nickname = #{nickname}, </if> <if test="email != null"> nickname = #{email} </if> <if test="phone != null"> nickname = #{phone} </if> </set> <where> id = #{id} </where> </update> </mapper>

删除数据

controller

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  //删除用户
  @DeleteMapping("/{id}")
  public Integer deletes(@PathVariable Integer id){
      return userMapper.deleteById(id);
  }

mapper

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  @Delete("delete from sys_user where id = #{id}")
  Integer deleteById(Integer id);

分页查询

controller

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  //分页查询
  @GetMapping("/pageList")
  public Object pageList(@RequestParam Integer  pageNum, @RequestParam Integer pageSize){
          pageNum = (pageNum - 1) * pageSize;
          //查询列表总数
          Integer selectTotal = userMapper.selectTotal();
          Map<String, Object> obj = new HashMap<>();
          obj.put("total",selectTotal);
          //分页数据
          List<User> data = userMapper.selectPage(pageNum,pageSize);
          obj.put("data",data);
          return obj;
  }

mapper

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  //分页查询
  @Select("SELECT * from sys_user limit #{pageNum}, #{pageSize}")
  List<User> selectPage(@Param("pageNum") Integer pageNum, @Param("pageSize") Integer pageSize);
  //查询总数
  @Select("select count(*) from sys_user")
  Integer selectTotal();