MyBatis框架注解开发
1. 注解方式单表的CRUD的操作
- SqlMapConfig.xml配置文件
2.UserMapper接口方法和注解的编写
package com.qcby.mapper;
import java.util.List;
import org.apache.ibatis.annotations.Delete;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Result;
import org.apache.ibatis.annotations.ResultMap;
import org.apache.ibatis.annotations.Results;
import org.apache.ibatis.annotations.Select;
import org.apache.ibatis.annotations.Update;
import com.qcby.domain.User;
/**
* 在MyBatis环境中，UserDao称为UserMapper接口
* @author Administrator
*/
public interface UserMapper {
@Select(value="select * from user")
@Results(id="userMap",value= {
@Result(id=true,column="id",property="id"),
@Result(column="username",property="username"),
@Result(column="birthday",property="birthday"),
@Result(column="sex",property="sex"),
@Result(column="address",property="address")
})
public List findAll();
@Select(value="select * from user where id = #{uid}")
@ResultMap(value="userMap")
public User findById(Integer uid);
// 保存
@Insert(value="insert into user (username,birthday,sex,address) values (#{username},#{birthday},#{sex},#{address})")
public void insert(User user);
// 修改
@Update("update user set username = #{username},birthday=#{birthday},sex=#{sex},address=#{address} where id = #{id}")
public void update(User user);
// 删除
@Delete("delete from user where id = #{id}")
public void delete(Integer userId);
// 查询数量
@Select("select count(*) from user")
public Integer findByCount();
// 模糊查询
@Select("select * from user where username like #{username}")
public List findByUsername(String username);
} 3.UserTest测试方法的编写
package com.qcby.test;
import java.io.InputStream;
import java.util.Date;
import java.util.List;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import com.qcby.domain.User;
import com.qcby.mapper.UserMapper;
public class UserTest {
private InputStream in;
private SqlSession session;
SqlSessionFactory factory;
private UserMapper mapper;
// 初始化的方法
@Before
public void init() throws Exception {
// 加载主配置文件
in = Resources.getResourceAsStream("SqlMapConfig.xml");
// 创建工厂对象
factory = new SqlSessionFactoryBuilder().build(in);
// 创建session
session = factory.openSession();
// 获取到代理对象
mapper = session.getMapper(UserMapper.class);
}
// 销毁的方法
@After
public void destory() throws Exception {
// 关闭资源
session.close();
in.close();
}
/**
* 测试查询
* @throws Exception
*/
@Test
public void testFindAll() throws Exception {
// 调用方法
List list = mapper.findAll();
for (User user : list) {
System.out.println(user);
}
}
@Test
public void testFindById() {
User user = mapper.findById(41);
System.out.println(user);
}
/**
* 保存
* @throws Exception
*/
@Test
public void testInsert() throws Exception {
// 创建User对象
User user = new User();
user.setUsername("美美2");
user.setBirthday(new Date());
user.setSex("女");
user.setAddress("监狱");
// 保存
mapper.insert(user);
session.commit();
}
/**
* 测试
* @throws Exception
*/
@Test
public void testUpdate() throws Exception {
// 先通过id查询
User user = mapper.findById(41);
// 设置新的数据内容
user.setUsername("熊大");
user.setAddress("深林深处");
// 修改
mapper.update(user);
session.commit();
}
/**
* 删除
* @throws Exception
*/
@Test
public void testDelete() throws Exception {
mapper.delete(2);
session.commit();
}
/**
* 查询的是聚合函数
* @throws Exception
*/
@Test
public void testFindByCount() throws Exception {
Integer count = mapper.findByCount();
System.out.println("总数量："+count);
}
/**
* 模糊查询
* @throws Exception
*/
@Test
public void testFindByUsername() throws Exception {
// 第一种测试的方式
List list = mapper.findByUsername("%王%");
for (User user : list) {
System.out.println(user);
}
}
}
2. 多对一的注解查询
1.多对一立即加载查询（推荐）
- AccountMapper接口编写方法和注解
/**
* 立即加载
* @return
*/
@Select("SELECT a.ID AS aid,a.UID,a.MONEY,u.* FROM account a,USER u WHERE a.UID = u.id")
@Results(value= {
@Result(id=true,column="aid",property="id"),
@Result(column="uid",property="uid"),
@Result(column="money",property="money"),
@Result(column="id",property="user.id"),
@Result(column="username",property="user.username"),
@Result(column="birthday",property="user.birthday"),
@Result(column="sex",property="user.sex"),
@Result(column="address",property="user.address")
})
public List findAll(); 2.AccountTest进行测试
package com.qcby.test;
import java.io.InputStream;
import java.util.List;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import com.qcby.domain.Account;
import com.qcby.mapper.AccountMapper;
public class AccountTest {
private InputStream in;
private SqlSession session;
private AccountMapper mapper;
// 初始化的方法
@Before
public void init() throws Exception {
// 加载主配置文件
in = Resources.getResourceAsStream("SqlMapConfig.xml");
// 创建工厂对象
SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
// 创建session
session = factory.openSession();
// 获取到代理对象
mapper = session.getMapper(AccountMapper.class);
}
// 销毁的方法
@After
public void destory() throws Exception {
// 关闭资源
session.close();
in.close();
}
/**
* 测试查询
* @throws Exception
*/
@Test
public void testFindAll() throws Exception {
// 调用方法
List list = mapper.findAll();
for (Account account : list) {
System.out.println(account);
}
}
} 2.多对一延迟加载查询
- AccountMapper编写方法和注解
/**
* 延迟加载
* @return
*/
@Select("select * from account")
@Results(value= {
@Result(id=true,column="aid",property="id"),
@Result(column="uid",property="uid"),
@Result(column="money",property="money"),
@Result(property="user",javaType=User.class,column="uid",one=@One(select="com.qcby.mapper.UserMapper.findById",fetchType=FetchType.LAZY))
})
public List findAll(); 2.UserMapper接口编写方法
@Select(value="select * from user where id = #{uid}")
public User findById(Integer uid);3.测试
package com.qcby.test;
import java.io.InputStream;
import java.util.List;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import com.qcby.domain.Account;
import com.qcby.mapper.AccountMapper;
public class AccountTest {
private InputStream in;
private SqlSession session;
private AccountMapper mapper;
// 初始化的方法
@Before
public void init() throws Exception {
// 加载主配置文件
in = Resources.getResourceAsStream("SqlMapConfig.xml");
// 创建工厂对象
SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(in);
// 创建session
session = factory.openSession();
// 获取到代理对象
mapper = session.getMapper(AccountMapper.class);
}
// 销毁的方法
@After
public void destory() throws Exception {
// 关闭资源
session.close();
in.close();
}
/**
* 测试查询
* @throws Exception
*/
@Test
public void testFindAll() throws Exception {
// 调用方法
List list = mapper.findAll();
for (Account account : list) {
System.out.println(account.getMoney());
System.out.println(account.getUser());
}
}
} 3. 一对多的注解查询
1.一对多查询，使用延迟加载的方式查询
2.UserMapper接口编写方法
/**
* 查询用户，延迟加载用户下的所有的账号
* @return
*/
@Select(value="select * from user")
@Results(id="userMap",value= {
@Result(id=true,column="id",property="id"),
@Result(column="username",property="username"),
@Result(column="birthday",property="birthday"),
@Result(column="sex",property="sex"),
@Result(column="address",property="address"),
@Result(property="accounts",column="id",many=@Many(select="com.qcby.mapper.AccountMapper.findByUid",fetchType=FetchType.LAZY))
})
public List findAll(); 3.测试
/**
* 测试查询
* @throws Exception
*/
@Test
public void testFindAll() throws Exception {
// 调用方法
List list = mapper.findAll();
for (User user : list) {
System.out.println(user.getUsername());
System.out.println(user.getAccounts());
}
}