mybatis框架——实战练习——第一个spring boot + mybatis项目——在第一个项目的基础上使用@Select注解查询某条数据

POJO类不变

因为使用注解，mybatis文件不要动。和之前一样。

<?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.test.mapper.UserMapper">
    <select id="findAll" resultType="com.test.entity.MyUser">
        select * from users
    </select>
    <select id="getUser" resultType="com.test.entity.MyUser" parameterType="int">
        select * from users where id = #{id}
    </select>
    <update id="updateUser" parameterType="com.test.entity.MyUser" >
        update users set id = #{id} , name = #{name} , age = #{age} where id = #{id}
    </update>
    <insert id="addUser" parameterType="com.test.entity.MyUser">
            insert into users(id,name,age) values ( #{id},#{name},#{age} )
    </insert>
    <delete id="delUser" parameterType="String">
        delete from users where name = #{name}
    </delete>
</mapper>

　　

usermapper文件：

package com.test.mapper;


import com.test.entity.MyUser;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Select;

import java.util.List;

@Mapper
public interface UserMapper {
    public List<MyUser> findAll();

    @Select("select * from users limit 10")
    public List<MyUser> findShi();


    public MyUser getUser( int id );


    public boolean updateUser( MyUser user);


    public boolean addUser( MyUser user);


    public boolean delUser ( String name);



    @Insert("insert into users(id,name,age) values(#{id},#{name},#{age})")
    public int insert(MyUser user);


    @Select("select * from users where id = #{id}")
    public MyUser queryAll(int id);

}

　　

service接口：

package com.test.service;


import com.test.entity.MyUser;

import java.util.List;

public interface UserService
{
    List<MyUser> findAll();

    List<MyUser> findShi();

    MyUser getUserForId(int id);

    boolean updateUserById(MyUser user);

    boolean addUserAdd(MyUser user);


    boolean delUserByName(String name);

    int insertUser(MyUser user);


    MyUser queryFindAll(int id);

}

　　

实现service接口：

package com.test.service.impl;


import com.test.entity.MyUser;
import com.test.mapper.UserMapper;
import com.test.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class UserServiceImpl implements UserService
{
    @Autowired
    UserMapper userMapper;
    @Override
    public List<MyUser> findAll()
    {
        return userMapper.findAll();
    }

    @Override
    public List<MyUser> findShi()
    {
        return userMapper.findShi();
    }

    @Override
    public MyUser getUserForId(int id)
    {
       MyUser user =   userMapper.getUser(id);

       return user;
    }

    @Override
    public boolean updateUserById(MyUser user)
    {
        boolean flag = false;

        flag = userMapper.updateUser(user);

        return flag;

    }


    @Override
    public boolean addUserAdd(MyUser user)
    {
        boolean flag = false;

        flag = userMapper.addUser(user);

        System.out.println(flag);

        return flag;

    }


    @Override
    public boolean delUserByName(String name)
    {
        boolean flag = false;

        flag = userMapper.delUser(name);

        return flag;

    }


    @Override
    public int insertUser(MyUser user)
    {
        int row = userMapper.insert(user);

        return row;
    }


    @Override
    public MyUser queryFindAll(int id)
    {
        return userMapper.queryAll(id);

    }




}

　　

新增一个controller：

package com.test.controller;

import com.test.entity.MyUser;
import com.test.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;


@RestController
public class FindALLController
{

    @Autowired
    private UserService userService;


    @GetMapping(value = "/8")
    public MyUser home8(@RequestParam("id")  int id)
    {
        MyUser user = userService.queryFindAll(id);

        return user;

    }

}

　　

http://localhost:8080/8?id=1001