SSM-MyBatis教程（一）-ORMpping技术|动态SQL|MyBatis实现1:1 以及 1:N关联关系|MyBatis逆向工程|综合案例|ResultMapping（详细）

川长思鸟来 2022-04-22 13:46 65阅读 0赞

## SSM-MyBatis ##

### 1、SSM： ###

SSM：Spring SpringMVC MyBaits 缩写，SSI：Spring SpringMVC iBatis，SSH：Spring Struts Hibernate

关于Hibernate和MyBatis，同属于持久化技术（数据持久化），

ORMapping技术：对象关系映射技术，将一个对象（User对象）映射成一行表数据（表中一条记录）

User user =new User();//

iBatis：是MyBatis的早期版本，iBatis升级到3.0时，将iBatis更名为MyBatis

Struts : mvc框架 Struts和SpringMVC的功能一致

### 2、MyBatis：MyBatis是一个轻量级的持久化框架（ORMapping技术） ###

### 3、MyBatis-基本的CURD操作以及MyBatis配置文件映射文件配置 ###

> ①、导入jar包
> 
> aopalliance-1.0.jar  
> cglib-2.2.2.jar  
> commons-logging-1.1.1.jar  
> hamcrest-core-1.3.jar  
> junit-4.12.jar  
> log4j-1.2.17.jar  
> mybatis-3.2.8.jar  
> mybatis-generator-core-1.3.5.jar  
> mybatis-spring-1.1.1.jar  
> mysql-connector-java-5.1.22-bin.jar  
> ojdbc14.jar
> 
> ②、配置MyBatis
> 
>     <?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>
>       <environments default="development">
>         <environment id="development">
>           <transactionManager type="JDBC"/>
>           <dataSource type="POOLED">
>             <property name="driver" value="com.mysql.jdbc.Driver"/>
>             <property name="url" value="jdbc:mysql://127.0.0.1:3306/newsystem"/>
>             <property name="username" value="root"/>
>             <property name="password" value="admin"/>
>           </dataSource>
>         </environment>
>       </environments>
>       <mappers>
>         <mapper resource="com/rock/dao/UserMapper.xml"/>
>       </mappers>
>     </configuration>
> 
> ③、配置映射文件
> 
>     <?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.rock.dao.UserDao">
>     
>     	<delete id="deleteUser" parameterType="java.lang.String">
>     		delete from user where userid=#{userid}	
>     	</delete>
>     	<delete id="deleteUserByUser" parameterType="com.rock.entities.User">
>     		delete from user where userid=#{userid}	
>     	</delete>
>     </mapper>
> 
> ④、通过SqlSession对象完成数据的CURD操作
> 
>     package com.rock.service;
>     
>     import java.io.IOException;
>     
>     import org.apache.ibatis.io.Resources;
>     import org.apache.ibatis.session.SqlSession;
>     import org.apache.ibatis.session.SqlSessionFactoryBuilder;
>     import org.junit.After;
>     import org.junit.Before;
>     import org.junit.Test;
>     
>     import com.rock.dao.UserDao;
>     import com.rock.entities.User;
>     
>     /**FileName: com.rock.service UserSerivce.java * TODO: * Copyright: Copyright (c) 2015-2016 All Rights Reserved. Company: 01skill-soft.com Inc. * @author: 老张 * @Date: 2019年9月18日:下午2:27:42 * @version: 1.0 * * Modification History: Date Author Version Description * ---------------------------------------------------------------------- * 2019年9月18日 老张 1.0 1.0 Version * */
>     public class UserSerivce { 
>     	private SqlSession sqlSession=null;
>     	private UserDao userDao=null;
>     	@Before
>     	public void init(){ 
>     		try { 
>     			sqlSession=new SqlSessionFactoryBuilder().build(Resources.getResourceAsStream("mybatis.xml")).openSession();
>     			userDao=sqlSession.getMapper(UserDao.class);
>     		} catch (IOException e) { 
>     			e.printStackTrace();
>     		}
>     	}
>     	@Test
>     	public void test_deleteUser(){ 
>     		System.out.println(userDao.deleteUser("abc"));
>     	}
>     	@Test
>     	public void test_deleteUserByUser(){ 
>     		User user=new User();
>     		user.setUserid("abc");
>     		userDao.deleteUserByUser(user);
>     	}
>     	@After
>     	public void commit(){ 
>     		sqlSession.commit();
>     	}
>     }
> 
>     <?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.rock.dao.UserDao">
>     	
>     	<delete id="deleteUser" parameterType="java.lang.String">
>     		delete from user where userid=#{userid}	
>     	</delete>
>     	
>     	<delete id="deleteUserByUser" parameterType="com.rock.entities.User">
>     		delete from user where userid=#{userid}	
>     	</delete>
>     	
>     	<update id="updateUser" parameterType="User">
>     		update user set password=#{password} where userid=#{userid}
>     	</update>
>     	
>     	<insert id="saveUser" parameterType="User">
>     		insert into user(userid,password,qid,anwser,score) values(#{userid},#{password},#{qid},#{anwser},#{score})
>     	</insert>
>     	
>     	<select id="queryById" parameterType="String" resultType="User">
>     		select * from user where userid=#{userid}
>     	</select>
>     	
>     	<select id="queryAll" resultType="User">
>     		select * from user
>     	</select>
>     </mapper>

### 4、动态SQL ###

UserDao.java

package com.rock.mybatis.dao;
    
    import java.util.List;
    import java.util.Map;
    
    import org.apache.ibatis.annotations.Param;
    
    import com.rock.mybatis.entities.User;
    
    /**FileName: com.rock.mybatis.dao UserDao.java * TODO: * Copyright: Copyright (c) 2015-2016 All Rights Reserved. Company: 01skill-soft.com Inc. * @author: 老张 * @Date: 2019年9月19日:下午2:16:21 * @version: 1.0 * * Modification History: Date Author Version Description * ---------------------------------------------------------------------- * 2019年9月19日 老张 1.0 1.0 Version * */
    public interface UserDao { 
    	public List<User> queryAll();
    	public User queryById(String userid);
    	public int  updateUser(User user);
    	public int  updateUserByIf(User user);
    	public List<User> queryAllByQid(String qid);
    	public List<User> queryAllByQid2Score(User user);
    	public List<User> queryAllBychooseWhenOtherwise(User user);
    	public List<User> queryAllByAnwser(String anwser);
    	public int  updateUserByTrim(User user);
    	public int saveUser(User user);
    	public int deleteBatch(String[] ids);
    	
    	public List<User> queryByMultiCondition(String qid,int score);
    	public List<User> queryByMultiConditionParam(@Param("qid1") String qid,@Param("score1")int score);
    	public List<User> queryByMultiConditionMap(Map<String,Object> params);
    	
    }

UserMapper.xml

<?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.rock.mybatis.dao.UserDao">
    	<resultMap type="com.rock.mybatis.entities.User" id="baseUserMap">
    		<id property="userid" column="userid"/>
    		<result property="password" column="password"/>
    		<result property="qid" column="qid"/>
    		<result property="anwser" column="anwser"/>
    		<result property="score" column="score"/>
    	</resultMap>
    	
    	
    	<sql id="BaseUserColumns">
    		userid userid,password,qid,anwser,score
    	</sql>
    	<sql id="BaseUserColumns1">
    		userid userid,password,qid,anwser,score
    	</sql>
    	
    	<select id="queryAll" resultMap="baseUserMap">
    		select <include refid="BaseUserColumns"/> from user
    	</select>
    	<select id="queryById" resultMap="baseUserMap" parameterType="String">
    		select <include refid="BaseUserColumns1"/> from user where userid=#{userid}
    	</select>
    	<update id="updateUser" parameterType="com.rock.mybatis.entities.User">
    		update user set password=#{password},qid=#{qid},anwser=#{anwser},score=#{score} where userid=#{userid}
    	</update>
    	
    	<update id="updateUserByIf" parameterType="com.rock.mybatis.entities.User">
    		update user set 
    		<if test="password !=null">
    			password=#{password}
    		</if>
    		
    		where userid=#{userid}
    	</update>
    	
    	<select id="queryAllByQid" resultMap="baseUserMap" parameterType="String">
    		select <include refid="BaseUserColumns"/> from user where qid=#{qid}
    	</select>
    	
    	
    	<select id="queryAllByQid2Score" resultMap="baseUserMap" parameterType="com.rock.mybatis.entities.User">
    		select <include refid="BaseUserColumns"/> 
    		from user 
    		where 1=1
    		<if test="qid!=null">
    			and qid=#{qid}	
    		</if>
    		<if test="score!=0"> 
    			 and score>#{score}
    		</if>
    	</select>
    	<select id="queryAllBychooseWhenOtherwise" parameterType="com.rock.mybatis.entities.User" resultMap="baseUserMap">
    		select <include refid="BaseUserColumns"/> from user
    		where 1=1
    		<choose>
    			<when test="qid!=null">
    				and qid=#{qid}
    			</when>
    			<when test="score!=0">
    				and score>#{score}
    			</when>
    			<when test="anwser!=null">
    				and anwser=#{anwser}
    			</when>
    			<otherwise>
    				and userid=#{userid}
    			</otherwise>
    		</choose>
    	
    	</select>
    	<select id="queryAllByAnwser" parameterType="String" resultMap="baseUserMap">
    		select <include refid="BaseUserColumns"/> from user 
    		<where>
    				anwser =#{anwser} 
    		</where>
    	</select>
    	<update id="updateUserByTrim" parameterType="com.rock.mybatis.entities.User">
    		update user 
    		
    		 <trim prefix="set" suffix="where userid=#{userid}" suffixOverrides=",">
    		 	<if test="password!=null">
    				password=#{password},
    		 	</if>
    		 	<if test="qid!=null">
    				qid=#{qid},
    		 	</if>
    		 	<if test="anwser!=null">
    				anwser=#{anwser},
    		 	</if>
    		 	<if test="score!=0">
    				score=#{score},
    		 	</if>
    		 </trim>
    	</update>
    	<insert id="saveUser" parameterType="com.rock.mybatis.entities.User">
    
    		insert into user
    		<trim prefix="(" suffix=")" suffixOverrides=",">
    			<if test="userid!=null">
    				userid,
    			</if>
    			<if test="password!=null">
    				password,
    			</if>
    			<if test="qid!=null">
    				qid,
    			</if>
    			<if test="anwser!=null">
    				anwser,
    			</if>
    			<if test="score!=0">
    				score,
    			</if>
    		</trim>
    		values
    		<trim prefix="(" suffix=")" suffixOverrides=",">
    			<if test="userid!=null">
    				#{userid},
    			</if>
    			<if test="password!=null">
    				#{password},
    			</if>
    			<if test="qid!=null">
    				#{qid},
    			</if>
    			<if test="anwser!=null">
    				#{anwser},
    			</if>
    			<if test="score!=0">
    				#{score},
    			</if>
    		</trim>
    	</insert>
    	<delete id="deleteBatch" parameterType="String">
    		delete from user where userid in
    		<foreach collection="array" open="(" close=")" separator="," item="ids">
    			#{ids}
    		</foreach>
    	</delete>
    
    	<select id="queryByMultiCondition" resultMap="baseUserMap">
    		select <include refid="BaseUserColumns"/> from user 
    		where
    		qid=#{0} and score>#{1}
    	</select>
    	<select id="queryByMultiConditionParam" resultMap="baseUserMap">
    		select <include refid="BaseUserColumns"/> from user 
    		where
    		qid=#{qid1} and score>#{score1}
    	</select>
    	<select id="queryByMultiConditionMap" resultMap="baseUserMap" parameterType="java.util.HashMap">
    		select <include refid="BaseUserColumns"/> from user 
    		where
    		qid=#{qid1} and score>#{score1} and anwser=#{anwser}
    	</select>
    </mapper>

UserTest.java

package com.rock.mybatis.entities;
    
    import java.io.IOException;
    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.SqlSessionFactoryBuilder;
    import org.junit.After;
    import org.junit.Before;
    import org.junit.Test;
    
    import com.rock.mybatis.dao.UserDao;
    
    /**FileName: com.rock.mybatis.entities UserTest.java * TODO: * Copyright: Copyright (c) 2015-2016 All Rights Reserved. Company: 01skill-soft.com Inc. * @author: 老张 * @Date: 2019年9月19日:下午2:19:28 * @version: 1.0 * * Modification History: Date Author Version Description * ---------------------------------------------------------------------- * 2019年9月19日 老张 1.0 1.0 Version * */
    public class UserTest { 
    	private UserDao userDao=null;
    	@Before
    	public void init(){ 
    		try { 
    			SqlSession sqlSession=new SqlSessionFactoryBuilder().build(Resources.getResourceAsStream("mybatis.xml")).openSession(true);
    			userDao=sqlSession.getMapper(UserDao.class);
    			System.out.println("UserTest.init() is running.............");
    		} catch (IOException e) { 
    			e.printStackTrace();
    		}
    	}
    	
    	@Test
    	public void test_queryAll(){ 
    		List<User> all=userDao.queryAll();
    		all.forEach((User user)->System.out.println(user));
    	}
    	@Test
    	public void test_queryById(){ 
    		User user=userDao.queryById("rock");
    		System.out.println(user);
    	}
    	@Test
    	public void test_updateUser(){ 
    		User user=new User();
    		user.setPassword("123456");
    		user.setUserid("admin");
    		System.out.println(userDao.updateUser(user));
    	}
    	@Test
    	public void test_updateUserByIf(){ 
    		User user=new User();
    		user.setPassword("admin");
    		user.setUserid("admin");
    		System.out.println(userDao.updateUserByIf(user));
    	}
    	@Test
    	public void test_queryAllByQid(){ 
    		List<User> all=userDao.queryAllByQid("1");
    		all.forEach((User user)->System.out.println(user));
    	}
    	@Test
    	public void test_queryAllByQid2Score(){ 
    		User user=new User();
    		user.setPassword("admin");
    		user.setUserid("admin");
    		user.setQid("1");
    		user.setScore(100);
    		List<User> all=userDao.queryAllByQid2Score(user);
    		all.forEach((User u)->System.out.println(u));
    	}
    	@Test
    	public void test_queryAllBychooseWhenOtherwise(){ 
    		User user=new User();
    		user.setPassword("admin");
    		user.setUserid("admin");
    		user.setQid("1");
    		user.setScore(100);
    		List<User> all=userDao.queryAllBychooseWhenOtherwise(user);
    		all.forEach((User u)->System.out.println(u));
    	}
    	@Test
    	public void test_queryAllByAnwser(){ 
    		List<User> all=userDao.queryAllByAnwser("中国");
    		all.forEach((User u)->System.out.println(u));
    	}
    	@Test
    	public void test_updateUserByTrim(){ 
    		User user=new User();
    		user.setUserid("admin");
    		user.setPassword("123456");
    		user.setQid("3");
    // user.setScore(600);
    		user.setAnwser("中国大连");
    		System.out.println(userDao.updateUserByTrim(user));
    	}
    	@Test
    	public void test_saveUser(){ 
    		User user=new User();
    		user.setUserid("ccc");
    		user.setPassword("123456");
    		user.setQid("2");
    		user.setScore(300);
    // user.setAnwser("中国大连");
    		System.out.println(userDao.saveUser(user));
    	}
    	@Test
    	public void test_deleteBatch(){ 
    		String []ids={ "aaa","bbb","ccc"};
    		System.out.println(userDao.deleteBatch(ids));
    	}
    	@Test
    	public void test_queryByMultiCondition(){ 
    		List<User> all=userDao.queryByMultiCondition("1",50);
    		all.forEach((User user)->System.out.println(user));
    	}
    	@Test
    	public void test_queryByMultiConditionParam(){ 
    		List<User> all=userDao.queryByMultiConditionParam("1",50);
    		all.forEach((User user)->System.out.println(user));
    	}
    	@Test
    	public void test_queryByMultiConditionMap(){ 
    		Map<String,Object> params=new HashMap<>();
    		params.put("qid1", "1");
    		params.put("score1", 10);
    		params.put("anwser","中国");
    		List<User> all=userDao.queryByMultiConditionMap(params);
    		all.forEach((User user)->System.out.println(user));
    	}
    	@After
    	public void after(){ 
    		System.out.println("UserTest.after() is running.......");
    	}
    }

### 5、多参数解决方法 ###

> ①、通过参数索引位置引用 \#\{0\} \#\{1\}…
> 
> ②、通过Param注解直接为参数定义引用标志 public User login(@Param(“uid”) String userid,@…)
> 
>  MyBatis: \#\{uid\}
> 
>  少量参数推荐使用的解决方法
> 
> ③、通过Map存放多条件 将Map中的key作为MyBatis应用的标志
> 
>  详见如下案例代码
> 
>  推荐多个参数情况下使用的方法
> 
> ④、将多个条件封装到Bean中，也是常用的一种解决方法，但是要根据实际需求确定

UserDao.java

package com.ssm.dao;
    
    import java.util.List;
    import java.util.Map;
    
    import org.apache.ibatis.annotations.Param;
    
    /**FileName: com.ssm.dao UserDao.java * TODO: * Copyright: Copyright (c) 2015-2016 All Rights Reserved. Company: 01skill-soft.com Inc. * @author: 老张 * @Date: 2019年9月20日:上午10:45:22 * @version: 1.0 * * Modification History: Date Author Version Description * ---------------------------------------------------------------------- * 2019年9月20日 老张 1.0 1.0 Version * */
    public interface UserDao { 
    	public User login(String userid,String password);
    	public User loginByUser(User user);
    	/** * @TODO :检索指定qid的且score高于50的所有数据 where qid=#{qid} and score>#{score} * @Date :2019年9月20日 上午10:59:32 * @Author :老张 * @param qid * @param score * @return : */
    	public List<User> queryByQidAndScore(@Param("ididid") String qid,@Param("sss") int score);
    	/** * @TODO :where qid=#{qid} and anwser=#{anwser} and score=#{score} * : Map<key ,value> * map中的元素1： qidqid ："1" * map中的元素2： an ："中国" * map中的元素3： s ：100 * * MyBatis:where qid=#{qidqid} and anwser=#{an} and score=#{s} * @Date :2019年9月20日 上午11:09:04 * @Author :老张 * @param params * @return : */
    	public List<User> queryByAidAndAnwserAndScore(Map<String,Object> params);
    }

UserMapper.xml

UserTest.java

package com.ssm.dao;
    
    import java.io.IOException;
    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.SqlSessionFactoryBuilder;
    import org.junit.Before;
    import org.junit.Test;
    
    /**FileName: com.ssm.dao UserTest.java * TODO: * Copyright: Copyright (c) 2015-2016 All Rights Reserved. Company: 01skill-soft.com Inc. * @author: 老张 * @Date: 2019年9月20日:上午10:51:02 * @version: 1.0 * * Modification History: Date Author Version Description * ---------------------------------------------------------------------- * 2019年9月20日 老张 1.0 1.0 Version * */
    public class UserTest { 
    	private UserDao userDao=null;
    	@Before
    	public void init(){ 
    		try { 
    			SqlSession sqlSession=new SqlSessionFactoryBuilder().build(Resources.getResourceAsStream("mybatis.xml")).openSession(true);
    			userDao=sqlSession.getMapper(UserDao.class);
    		} catch (IOException e) { 
    			e.printStackTrace();
    		}
    	}
    	@Test
    	public void test_loginByUser(){ 
    		User user=userDao.loginByUser(new User("rock","admin"));
    		System.out.println(user);
    	}
    	@Test
    	public void test_login(){ 
    		User user=userDao.login("rock","admin");
    		System.out.println(user);
    	}
    	@Test
    	public void test_queryByQidAndScore(){ 
    		List<User> users=userDao.queryByQidAndScore("1",50);
    		users.forEach((User user)->System.out.println(user));
    	}
    	@Test
    	public void test_queryByAidAndAnwserAndScore(){ 
    		Map<String,Object> params=new HashMap<>();
    		params.put("qidqid","1");
    		params.put("an","中国");
    		params.put("s",100);
    		
    		List<User> users=userDao.queryByAidAndAnwserAndScore(params);
    		users.forEach((User user)->System.out.println(user));
    	}
    }

### 6、MyBatis模糊检索的实现 ###

> ①、通过字符串拼接方式组装SQL文 不推荐
> 
> ②、通过在实参中编写模糊检索的通配符方式 推荐
> 
> ③、通过元素完成 推荐
> 
>     UserDao.java
>     	public List<User> queryByLike(@Param("a") String aa);
>     	public List<User> queryByLike1(@Param("a") String aa);
>     	public List<User> queryByLike2(User user);
>     
>     MyBatis配置
>     <select id="queryByLike" resultMap="baseUserMap" parameterType="String">
>     		select <include refid="BaseUserColumns"/> 
>     		from user where 1=1
>     		<if test="a!=null">
>     			and userid like #{ a}
>     		</if>
>     	</select>
>     	
>     	<select id="queryByLike1" resultMap="baseUserMap" parameterType="String">
>     		select <include refid="BaseUserColumns"/> 
>     		from user where 1=1
>     		<if test="a!=null">
>     			and userid like '%${a}%'
>     		</if>
>     	</select>
>     	<select id="queryByLike2" resultMap="baseUserMap" parameterType="com.ssm.dao.User">
>     		
>     		<bind name="likePattern" value="'%'+_parameter.userid+'%'"/>
>     		select <include refid="BaseUserColumns"/> 
>     		from user where 1=1
>     		<if test="userid!=null">
>     			and userid like #{ likePattern}
>     		</if>
>     	</select>
>     	
>     测试代码：          
>     @Test
>     	public void test_queryByLike(){ 
>     		List<User> users=userDao.queryByLike("%r%");
>     		users.forEach((User user)->System.out.println(user));
>     	}
>     	@Test
>     	public void test_queryByLike1(){ 
>     		List<User> users=userDao.queryByLike1("r");
>     		users.forEach((User user)->System.out.println(user));
>     	}
>     	@Test
>     	public void test_queryByLike2(){ 
>     		User u=new User();
>     		u.setUserid("r");
>     		List<User> users=userDao.queryByLike2(u);
>     		users.forEach((User user)->System.out.println(user));
>     	}

### 7、MyBatis联级检索 ###

> ①、1:1关系下的联级检索
> 
> ②、n:1关系下的联级检索

Emplpoyee.java

public class Employee { 
    	private String empno;
    	private String ename;
    	private String email;
    	private String emobile;
    	private String deptno;
    	private String sex;
    	private Department department;
    }
    public class Department { 
    	private String deptno;
    	private String dname;
    	private String location;
    }

< ②、n:1关系下的联级检索

public class Department { 
    	private String deptno;
    	private String dname;
    	private String location;
    	private List<Employee> emps;
    } 
        public class Employee { 
    	private String empno;
    	private String ename;
    	private String email;
    	private String emobile;
    	private String deptno;
    	private String sex;
    }
    public interface IDepartmentDao { 
    	public Department queryById(@Param("no") String deptno);
    }
    
    <?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="mybatis.dao.IDepartmentDao">
    	<resultMap type="mybatis.entities.Department" id="BaseDepartmentMap">
    		<id column="deptno" property="deptno"/>
    		<result column="dname" property="dname"/>
    		<result column="location" property="location"/>
    		
    		<collection property="emps" ofType="mybatis.entities.Employee" column="deptno" select="queryAllEmployeeByDeptno"></collection>
    	</resultMap>
    	<select id="queryAllEmployeeByDeptno" resultType="mybatis.entities.Employee">
    		select * from employee where deptno=#{ deptno}
    	</select>
    	
    	<select id="queryById" resultMap="BaseDepartmentMap">
    		select * from department where deptno=#{ no}
    	</select>
    </mapper>

### 8、MyBatis逆向工程 ###

<?xml version="1.0" encoding="UTF-8"?>
    <!DOCTYPE generatorConfiguration PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN" "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">
    
    <generatorConfiguration>
      <context id="DB2Tables" targetRuntime="MyBatis3">
      	<commentGenerator>
      		<property name="suppressAllComments" value="true"/>
      	</commentGenerator>
      	
        <jdbcConnection driverClass="com.mysql.jdbc.Driver" connectionURL="jdbc:mysql://127.0.0.1:3306/newsystem" userId="root" password="admin">
        </jdbcConnection>
    
        <javaTypeResolver >
          <property name="forceBigDecimals" value="false" />
        </javaTypeResolver>
    	
        <javaModelGenerator targetPackage="mybatis.generater.entities" targetProject=".\src">
          <property name="enableSubPackages" value="true" />
          <property name="trimStrings" value="true" />
        </javaModelGenerator>
    
    	
        <sqlMapGenerator targetPackage="mybatis.generater.dao.mapper" targetProject=".\src">
          <property name="enableSubPackages" value="true" />
        </sqlMapGenerator>
    
    	
        <javaClientGenerator type="XMLMAPPER" targetPackage="mybatis.generater.dao" targetProject=".\src">
          <property name="enableSubPackages" value="true" />
        </javaClientGenerator>
    
        <table tableName="news" domainObjectName="News" ></table>
        <table tableName="newstype" domainObjectName="NewsType" ></table>
    
      </context>
    </generatorConfiguration>

public static void main(String[] args) throws IOException, XMLParserException, InvalidConfigurationException, SQLException, InterruptedException { 
    		 List<String> warnings = new ArrayList<String>();
    		   boolean overwrite = true;
    		   ConfigurationParser cp = new ConfigurationParser(warnings);
    		   Configuration config = cp.parseConfiguration(Test.class.getResourceAsStream("mbg.xml"));
    		   DefaultShellCallback callback = new DefaultShellCallback(overwrite);
    		   MyBatisGenerator myBatisGenerator = new MyBatisGenerator(config, callback, warnings);
    		   myBatisGenerator.generate(null);
    	}
    
    public class Test { 
    	public static void main(String[] args) throws IOException { 
    		NewsMapper newsMapper=new SqlSessionFactoryBuilder().build(Resources.getResourceAsStream("mybatis.xml")).openSession(true).getMapper(NewsMapper.class);
    		
    		News news=newsMapper.selectByPrimaryKey(174);
    		System.out.println(news);
    	}
    }

log4j.properties

log4j.rootLogger=DEBUG, Console
    #Console
    log4j.appender.Console=org.apache.log4j.ConsoleAppender
    log4j.appender.Console.layout=org.apache.log4j.PatternLayout
    log4j.appender.Console.layout.ConversionPattern=%d [%t] %-5p [%c] - %m%n
    log4j.logger.java.sql.ResultSet=INFO
    log4j.logger.org.apache=INFO
    log4j.logger.java.sql.Connection=DEBUG
    log4j.logger.java.sql.Statement=DEBUG
    log4j.logger.java.sql.PreparedStatement=DEBUG