mybatis基础---基本使用

主类：

public class Test01_SelectAll {
public static void main(String[] args) throws IOException {
//1 加载配置文件
// 1.1 获得资源流
InputStream is = Resources.getResourceAsStream("SqlMapConfig.xml");
// 1.2 获得工厂
SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(is);
//2 获得会话(连接)
SqlSession session = factory.openSession();
//3获得功能接口
UserMapper userMapper = session.getMapper(UserMapper.class);
//4 调用功能
List userList = userMapper.selectAll();
//5 打印查询结果
for (User user : userList) {
System.out.println(user);
}
//6 释放资源
session.close();
}
}

mapper类：

public interface UserMapper {

@Select("select * from user")
public List selectAll;
}

JavaBean类(生成get，set，tostring方法)：

 public class User {
     private String uid; 
     private String username; 
     private String password;
     private String name; 
     private String email; 
     private Date birthday; 
     private String sex; 
     private Integer state;
     private String code;  
 }

JavaBean类(生成get，set，tostring方法)：

public class UserVo {
private String beginTime; // 开始时间
private String endTime; // 结束时间
}

mapper类：

@Select("select * from user where birthday >= #{beginTime} and birthday
<= #{endTime}")
public List condition(UserVo userVo);

主类：

public class Test07_Condition {
public static void main(String[] args) {
UserMapper userMapper = MyBatisUtils.getMapper(UserMapper.class);
List list = userMapper.condition(new UserVo("2010-01-01",
"2021-01-01"));
// 打印
list.forEach(user -> {
System.out.println(user);
});
MyBatisUtils.commitAndclose();
}
}

语法：

@Results(value = {
@Result(property = "属性名", column = "字段名", id = true),
@Result(property = "属性名2", column = "字段名2"),
@Result(property = "属性名3", column = "字段名3")
})

基本使用：

@Select("select * from user")
@Results({
@Result(property = "uid", column = "uid", id = true),
@Result(property = "username", column = "username"),
@Result(property = "password", column = "password")
})
public List selectAll();

重复使用(语法)：

@Select(...)
@Results(id = "标识", value = {...})
public 返回值 方法名();
@Select(...)
@ResultMap("标识")
public 返回值 方法名2();

（使用）

@Select("select * from user")
@Results(id = "userResult", value = {
@Result(property = "uid", column = "uid", id = true),
@Result(property = "username", column = "username"),
@Result(property = "password", column = "password")
})
public List selectAll();

@Select("select * from user where uid = #{uid}")
@ResultMap("userResult")
public User selectById(@Param("uid") String uid);

注解名称 描述

@Insert 添加sql

@Update 更新sql

@Delete 删除sql

@Select 查询sql

@Param 形参命名

@Results 对象和表的映射关系。

@Result 一个对象属性和一个表的字段的映射关系。