<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>2.2.0</version>
</dependency>

mybatis:
  mapper-locations: classpath:mybatis/*.xml
  type-aliases-package: com.java18.vipmgr.pojo

<?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.java18.vipmgr.mapper.UserMapper">
    <select id="getAllUsers" resultType="User">
        select * from users
    </select>
</mapper>

@Mapper
public interface UserMapper {
    public List<User> getAllUsers();
}

@Data
public class User {
    private Integer id;
    private String username;
    private String password;
    private Integer points;
}

mybatis:
  mapper-locations: classpath:mybatis/*.xml
  <font color="#c24f4a">type-aliases-package: com.java18.vipmgr.pojo</font>

@Autowired
UserMapper userMapper;

@GetMapping("getAllViaMybatis")
public  List<User> getAllViaMybatis(){
    return userMapper.getAllUsers();
}

@Mapper
public interface UserMapper {
    public List<User> getAllUsers();
​
    @Select("select * from users where id = #{param1}")
    User findById(String id);
​
}

@GetMapping("findById")
public  User findById(String id){
    return userMapper.findById(id);
}

@Update("insert into users values (null,#{username},#{password},#{points})")
void addUser(User user);

@GetMapping("addUser")
public  boolean addUser(){
    User user = new User();
    user.setUsername("wangwu");
    user.setPassword("123");
    user.setPoints(1000);
    userMapper.addUser(user);
    return true;
}

<dependency>
    <groupId>com.github.pagehelper</groupId>
    <artifactId>pagehelper-spring-boot-starter</artifactId>
    <version>1.3.1</version>
</dependency>

@GetMapping("getAllViaMybatis")
public  PageInfo getAllViaMybatis(int page,int rows){
    PageHelper.startPage(page,rows);
    PageInfo pageInfo = new PageInfo(userMapper.getAllUsers());
    return pageInfo;
}

<insert id="insertEmp" parameterType="org.zhang.pojo.Emp">
    insert into emp (ename,job,hiredate,sal) values (#{ename},#{job},#{hiredate},#{sal});
    <selectKey resultType="int" keyColumn="empno" keyProperty="empno" order="AFTER">
        select last_insert_id()
    </selectKey>
</insert>

<!--    此時(shí)因?yàn)橛卸鄠€(gè)參數(shù)  所以參數(shù)類(lèi)型不能逐一制定 可以省略  有mybatis自動(dòng)匹配-->
    <update id="updateEmpByNo2">
            update emp set ename=#{param1} where empno=#{param2}
    </update>

public void updateEmpByNo2(@Param("name") String ename,@Param("no") Integer empno) throws IOException;
<update id="updateEmpByNo2">
        update emp set ename=#{name} where empno=#{no}
</update>

重點(diǎn)就是 parameterType="hashmap" 這句話(huà)

public void updateEmpByNo3(Map<String,Object> argMap) throws IOException;
<update id="updateEmpByNo3" parameterType="hashmap">
        update emp set ename=#{name} where empno=#{no}
</update>

public User selectUser(Emp emp);
  
 <select id="selectUser" parameterType="org.zhang.pojo.Emp" resultMap="Emp">
     select * from user
     where user_name = #{userName} and dept_id = #{deptId}
 </select>

string wildcardname = “%smi%”;
list<name> names = mapper.selectlike(wildcardname);

string wildcardname = “smi”;
list<name> names = mapper.selectlike(wildcardname);
​
 <span style="color: inherit;">對(duì)應(yīng)的xml：</span>
    <select id=”selectlike”>
         select * from foo where bar like "%"${value}"%"
    </select>

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.3.1.tmp</version>
</dependency>

mybatis-plus:
  mapper-locations: classpath:mybatis/*.xml
  type-aliases-package: com.java18.vipmgr.pojo

@Data
@TableName("users")
public class User {
    private Integer id;
    private String username;
    private String password;
    private Integer points;
}

public interface UserMapper extends BaseMapper<User> {
 //省略之前的代碼
}

@GetMapping("getAllViaMybatisPlus")
public  IPage<User> getAllViaMybatisPlus(Integer page,Integer rows){
    IPage<User> pageInfo = new Page<>(page, rows);//參數(shù)一是當(dāng)前頁(yè)，參數(shù)二是每頁(yè)個(gè)數(shù)
    QueryWrapper<User> wrapper = new QueryWrapper<>();
    pageInfo = userMapper.selectPage(pageInfo,wrapper);
    return pageInfo;
}