mybatis
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/ssm
jdbc.username=root
jdbc.password=root
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<!-- <properties>
<property name="jdbc.driver" value="com.mysql.jdbc.Driver"/>
</properties> -->
<!--
<properties>:设置或引入资源文件
resource:在类路径下访问资源文件
url:在网络路径或磁盘路径下访问资源文件
-->
<properties resource="jdbc.properties"></properties>
<settings>
<!-- 将下划线映射成驼峰,user_name映射为userName -->
<setting name="mapUnderscoreToCamelCase" value="true"/>
<!-- 开启延迟加载 -->
<setting name="lazyLoadingEnabled" value="true"/>
<!-- 是否查询所有数据 -->
<setting name="aggressiveLazyLoading" value="false"/>
</settings>
<typeAliases>
<!--
为类型设置类型别名
type:Java 类型,若只设置type,默认的别名就是类型,且不区分大小写
-->
<!-- <typeAlias type="com.atguigu.bean.User" alias="u"/> -->
<package name="com.atguigu.bean"/>
</typeAliases>
<!--
<environments>:设置连接数据库的环境
default:设置默认使用的数据库环境
-->
<environments default="mysql">
<!--
<environment>:设置某个具体的数据库的环境
id:数据库环境的唯一标示
-->
<environment id="mysql">
<!-- type="JDBC|MANAGED",JDBC:使用JDBC原生的事务管理方式,即提交和回滚都需要手动处理 -->
<transactionManager type="JDBC" />
<!-- type="POOLED|UNPOOLED|JNDI" -->
<dataSource type="POOLED">
<property name="driver" value="${jdbc.driver}" />
<property name="url" value="${jdbc.url}" />
<property name="username" value="${jdbc.username}" />
<property name="password" value="${jdbc.password}" />
</dataSource>
</environment>
<environment id="oracle">
<transactionManager type="JDBC" />
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver" />
<property name="url" value="jdbc:mysql://localhost:3306/ssm" />
<property name="username" value="root" />
<property name="password" value="123456" />
</dataSource>
</environment>
</environments>
<!-- 引入映射文件 -->
<mappers>
<!-- <mapper resource="EmpMapper.xml" />
<mapper resource="DeptMapper.xml" /> -->
<!-- 此种写法要求mapper接口和mapper映射文件必须在同一个包下 -->
<package name="com.atguigu.mapper"/>
</mappers>
</configuration>
<?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.atguigu.mapper.ParamMapper">
<!-- void insertEmp(Emp emp); -->
<!--
useGeneratedKeys:可以使用自动生成的主键
keyProperty:将自动生成的主键赋值给传递过来的参数的哪一个属性
-->
<insert id="insertEmp" useGeneratedKeys="true" keyProperty="eid">
<!-- insert into emp values(null, #{ename}, #{age}, #{sex}) -->
insert into emp values(null, '${ename}', '${age}', '${sex}')
</insert>
<!-- Emp getEmpByEid(String eid); -->
<select id="getEmpByEid" resultType="Emp">
<!-- select eid,ename,age,sex from emp where eid = #{eid} -->
<!-- select eid,ename,age,sex from emp where eid = ${param} -->
<!-- select eid,ename,age,sex from emp where eid = ${value} -->
<!-- select eid,ename,age,sex from emp where eid = #{aaa}这个aaa是可以随意的,没有对应关系,但建议写传的形参名 -->
select eid,ename,age,sex from emp where eid = #{eid}
</select>
<!-- Emp getEmpByEidAndEname(String eid, String ename); -->
<select id="getEmpByEidAndEname" resultType="Emp">
select eid,ename,age,sex from emp where eid = ${param1} and ename = '${param2}'
</select>
<!-- Emp getEmpByMap(Map<String, Object> map); -->
<select id="getEmpByMap" resultType="emp">
select eid,ename,age,sex from emp where eid = ${eid} and ename = '${ename}'
</select>
<!-- Emp getEmpByEidAndEnameByParam(@Param("eid")String eid, @Param("ename")String ename);
这个有点疑问
-->
<select id="getEmpByEidAndEnameByParam" resultType="Emp">
select eid,ename,age,sex from emp where eid = #{eid} and ename = #{ename}
</select>
</mapper>
package com.atguigu.mapper;
import java.util.Map;
import org.apache.ibatis.annotations.Param;
import com.atguigu.bean.Emp;
public interface ParamMapper {
//添加员工信息
void insertEmp(Emp emp);
//根据eid获取员工信息
Emp getEmpByEid(String eid);
//根据eid和ename查询员工信息
Emp getEmpByEidAndEname(String eid, String ename);
//根据map查询员工信息
Emp getEmpByMap(Map<String, Object> map);
//根据eid和ename查询员工信息
Emp getEmpByEidAndEnameByParam(@Param("eid")String eid, @Param("ename")String ename);
}
package com.atguigu.test;
import java.io.IOException;
import java.io.InputStream;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
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.Test;
import com.atguigu.bean.Emp;
import com.atguigu.mapper.EmpMapper;
import com.atguigu.mapper.ParamMapper;
public class TestParam {
@Test
public void testCRUD() throws IOException {
InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
//SqlSession sqlSession = sqlSessionFactory.openSession();//需要手动处理事务
SqlSession sqlSession = sqlSessionFactory.openSession(true);//自动处理事务
ParamMapper mapper = sqlSession.getMapper(ParamMapper.class);
/*Emp emp = new Emp(null, "admin", 23, "男");*/
/*mapper.insertEmp(emp);
System.out.println(emp.getEid());*/
/*Emp emp = mapper.getEmpByEid("1");
System.out.println(emp);*/
/*Emp emp = mapper.getEmpByEidAndEname("1", "张三");
System.out.println(emp);*/
Map<String, Object> map = new HashMap<>();
map.put("eid", "1");
map.put("ename", "张三");
Emp emp = mapper.getEmpByMap(map);
/*Emp emp = mapper.getEmpByEidAndEnameByParam("1", "张三");*/
System.out.println(emp);
}
}
<?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.atguigu.mapper.EmpSelectMapper">
<!-- Emp getEmpByEid(String eid); -->
<select id="getEmpByEid" resultType="Emp">
select eid,ename,age,sex from emp where eid = #{eid}
</select>
<!-- Integer getCount(); -->
<select id="getCount" resultType="Integer">
select count(eid) from emp
</select>
<!-- Emp getEmpMapByEid(String eid); -->
<select id="getEmpMapByEid" resultType="java.util.HashMap">
select eid,ename,age,sex from emp where eid = #{eid}
</select>
<!-- Map<String, Object> getAllEmpMap(); -->
<select id="getAllEmpMap" resultType="Emp">
select eid,ename,age,sex from emp
</select>
</mapper>
package com.atguigu.mapper;
import java.util.List;
import java.util.Map;
import org.apache.ibatis.annotations.MapKey;
import com.atguigu.bean.Emp;
public interface EmpSelectMapper {
//根据eid查询一个员工信息
Emp getEmpByEid(String eid);
//获取所有的员工的数量
Integer getCount();
//以map集合获取一个员工信息
Map<String, Object> getEmpMapByEid(String eid);
//以map集合获取所有员工信息
@MapKey("eid")//设置map的键,因为在查询时传出所有的员工信息,可以把员工信息作为值,但是必须设置键
Map<String, Object> getAllEmpMap();
}
package com.atguigu.test;
import java.io.IOException;
import java.io.InputStream;
import java.util.Map;
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.Test;
import com.atguigu.bean.Emp;
import com.atguigu.mapper.EmpMapper;
import com.atguigu.mapper.EmpSelectMapper;
public class TestSelect {
@Test
public void testSelect() throws IOException {
InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
//SqlSession sqlSession = sqlSessionFactory.openSession();//需要手动处理事务
SqlSession sqlSession = sqlSessionFactory.openSession(true);//自动处理事务
EmpSelectMapper mapper = sqlSession.getMapper(EmpSelectMapper.class);
//若查询出的数据有多条,则绝对不能将接口中该方法的返回值设置为Javabean
/*Emp emp = mapper.getEmpByEid("3");
System.out.println(emp);*/
//获取员工总记录数
/*Integer i = mapper.getCount();
System.out.println(i);*/
//以map获取单个emp
/*Map<String, Object> map = mapper.getEmpMapByEid("6");
System.out.println(map);*/
//以map获取所有emp
Map<String, Object> map = mapper.getAllEmpMap();
System.out.println(map);
}
}
<?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.atguigu.mapper.EmpMapper">
<!-- Emp getEmpByEid(String eid); -->
<select id="getEmpByEid" resultType="Emp">
select eid,ename,age,sex from emp where eid = #{eid}
</select>
<!-- List<Emp> getAllEmp(); -->
<select id="getAllEmp" resultType="Emp">
select eid,ename,age,sex from emp
</select>
<!-- void addEmp(Emp emp); -->
<insert id="addEmp">
insert into emp values(null,#{ename},#{age},#{sex})
</insert>
<!-- void updateEmp(Emp emp); -->
<update id="updateEmp">
update emp set ename = #{ename}, age = #{age}, sex = #{sex} where eid = #{eid}
</update>
<!-- void deleteEmp(String eid); -->
<delete id="deleteEmp">
delete from emp where eid = #{eid}
</delete>
</mapper>
package com.atguigu.mapper;
import java.util.List;
import com.atguigu.bean.Emp;
public interface EmpMapper {
//根据eid查询一个员工信息
Emp getEmpByEid(String eid);
//获取所有的员工信息
List<Emp> getAllEmp();
//添加员工信息
void addEmp(Emp emp);
//修改员工信息
void updateEmp(Emp emp);
//删除员工信息
Boolean deleteEmp(String eid);
}
package com.atguigu.test;
import java.io.IOException;
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.Test;
import com.atguigu.bean.Emp;
import com.atguigu.mapper.EmpMapper;
public class TestCRUD {
@Test
public void testCRUD() throws IOException {
InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
//SqlSession sqlSession = sqlSessionFactory.openSession();//需要手动处理事务
SqlSession sqlSession = sqlSessionFactory.openSession(true);//自动处理事务
EmpMapper empMapper = sqlSession.getMapper(EmpMapper.class);
//测试:根据eid获取员工信息
/*Emp emp = empMapper.getEmpByEid("3");
System.out.println(emp);*/
//测试:获取所有的员工信息
/*List<Emp> list = empMapper.getAllEmp();
System.out.println(list);*/
//测试:添加员工信息
/*empMapper.addEmp(new Emp(null, "admin", 23, "女"));
sqlSession.commit();//提交事务*/
//测试:修改员工信息
empMapper.updateEmp(new Emp(6, "张二", 33, "女"));
//测试:删除员工信息
/*Boolean i = empMapper.deleteEmp("2");
System.out.println("result:"+i);*/
//select 字段名 from 表名 where 条件 group by 字段名 having 条件 order by 字段名 desc/asc limit index,pageSize
}
}
<?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.atguigu.mapper.EmpDeptMapper">
<!-- <resultMap type="Emp" id="empMap">
<id column="eid" property="eid"/>
<result column="ename" property="ename"/>
<result column="age" property="age"/>
<result column="sex" property="sex"/>
<result column="did" property="dept.did"/>
<result column="dname" property="dept.dname"/>
</resultMap> -->
<!--
<resultMap>:自定义映射,处理复杂的表关系
<id column="eid" property="eid"/>
<id>:设置主键的映射关系,column设置字段名,property设置属性名
<result column="ename" property="ename"/>
<result>:设置非主键的映射关系,column设置字段名,property设置属性名
-->
<resultMap type="Emp" id="empMap">
<id column="eid" property="eid"/>
<result column="ename" property="ename"/>
<result column="age" property="age"/>
<result column="sex" property="sex"/>
<association property="dept" javaType="Dept">
<id column="did" property="did"/>
<result column="dname" property="dname"/>
</association>
</resultMap>
<!-- List<Emp> getAllEmp(); -->
<select id="getAllEmp" resultMap="empMap">
select e.eid,e.ename,e.age,e.sex,e.did,d.dname from emp e left join dept d on e.did = d.did
</select>
<!--
<resultMap>:自定义映射,处理复杂的表关系
-->
<resultMap type="Emp" id="empMapStep">
<id column="eid" property="eid"/>
<result column="ename" property="ename"/>
<result column="age" property="age"/>
<result column="sex" property="sex"/>
<!--
select:分步查询的SQL的id,即接口的全限定名.方法名或namespace.SQL的id
column:分步查询的条件,注意:此条件必须是从数据库查询过得
-->
<association property="dept" select="com.atguigu.mapper.DeptMapper.getDeptByDid" column="did"/>
</resultMap>
<!-- Emp getEmpStep(String eid); -->
<select id="getEmpStep" resultMap="empMapStep">
select eid,ename,age,sex,did from emp where eid = #{eid}
</select>
<resultMap type="Dept" id="deptMap">
<id column="did" property="did"/>
<result column="dname" property="dname"/>
<!--
<collection>:处理一对多和多对多的关系
ofType:指集合中的类型,不需要指定javaType
-->
<collection property="emps" ofType="Emp">
<id column="eid" property="eid"/>
<result column="ename" property="ename"/>
<result column="age" property="age"/>
<result column="sex" property="sex"/>
</collection>
</resultMap>
<!-- Dept getDeptEmpsByDid(String did); -->
<select id="getDeptEmpsByDid" resultMap="deptMap">
select d.did,d.dname,e.eid,e.ename,e.age,e.sex from dept d left join emp e on d.did = e.did where d.did = #{did}
</select>
<!-- List<Emp> getEmpListByDid(String did); -->
<select id="getEmpListByDid" resultType="Emp">
select eid,ename,age,sex from emp where did = #{did}
</select>
<resultMap type="Dept" id="deptMapStep">
<id column="did" property="did"/>
<result column="dname" property="dname"/>
<collection property="emps" select="com.atguigu.mapper.EmpDeptMapper.getEmpListByDid" column="{did=did}" fetchType="eager"></collection>
</resultMap>
<!-- Dept getOnlyDeptByDid(String did); -->
<select id="getOnlyDeptByDid" resultMap="deptMapStep">
select did,dname from dept where did = #{did}
</select>
</mapper>
package com.atguigu.mapper;
import java.util.List;
import com.atguigu.bean.Dept;
import com.atguigu.bean.Emp;
public interface EmpDeptMapper {
List<Emp> getAllEmp();
Emp getEmpStep(String eid);
Dept getDeptEmpsByDid(String did);
Dept getOnlyDeptByDid(String did);
List<Emp> getEmpListByDid(String did);
}
package com.atguigu.test;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
import java.util.Map;
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.Test;
import com.atguigu.bean.Dept;
import com.atguigu.bean.Emp;
import com.atguigu.mapper.EmpDeptMapper;
import com.atguigu.mapper.EmpMapper;
import com.atguigu.mapper.EmpSelectMapper;
public class TestEmpDept {
@Test
public void testSelect() throws IOException {
InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
//SqlSession sqlSession = sqlSessionFactory.openSession();//需要手动处理事务
SqlSession sqlSession = sqlSessionFactory.openSession(true);//自动处理事务
EmpDeptMapper mapper = sqlSession.getMapper(EmpDeptMapper.class);
/*List<Emp> emp = mapper.getAllEmp();
System.out.println(emp);*/
/*Emp emp = mapper.getEmpStep("3");
System.out.println(emp.getEname());
System.out.println("=======================");
System.out.println(emp.getDept());*/
/*Dept dept = mapper.getDeptEmpsByDid("2");
System.out.println(dept);*/
Dept dept = mapper.getOnlyDeptByDid("1");
System.out.println(dept.getDname());
System.out.println("=======================");
System.out.println(dept.getEmps());
}
}