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）
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.jar②、配置MyBatis
<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
<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(); } }<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
<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
* 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
<mapper namespace="com.ssm.dao.UserDao">
<resultMap type="com.ssm.dao.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>
<select id="loginByUser" resultMap="baseUserMap" parameterType="com.ssm.dao.User">
select <include refid="BaseUserColumns"/> from user where userid=#{userid} and password=#{password}
select>
<select id="login" resultMap="baseUserMap">
select <include refid="BaseUserColumns"/>
from user where userid=#{0} and password=#{1}
select>
<select id="queryByQidAndScore" resultMap="baseUserMap">
select <include refid="BaseUserColumns"/>
from user where qid=#{ididid} and score>#{sss}
select>
<select id="queryByAidAndAnwserAndScore" resultMap="baseUserMap" parameterType="hashMap">
select <include refid="BaseUserColumns"/>
from user where qid=#{qidqid} and anwser=#{an} and score=#{s}
select>
mapper>
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 * from user where 1=1 and userid like +"%"+"'"+a的值+"'"+"%"; 注意： 在MyBatis中 拥有#{}的配置，MyBatis以预处理的方式组装SQL文 而${}的配置，MyBatis是以字符串拼接的方式组装的SQL文 --> <select id="queryByLike1" resultMap="baseUserMap" parameterType="String"> select <include refid="BaseUserColumns"/> from user where 1=1 <if test="a!=null"> and userid like '%${a}%' </if> </select> <select id="queryByLike2" resultMap="baseUserMap" parameterType="com.ssm.dao.User"> <!-- bind：将如下变量绑定到当前select配置中。然后就可以在当前配置中通过#{变量名}访问其值了 name属性：指定了变量名 value属性：指定了这个变量对应的值 userid like '%'+r+'%'; _parameter:MyBatis中内置的一个对象，其对应了参数中的那个bean对象 '%r%' --> <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
<resultMap type="mybatis.entities.Employee" id="BaseEmployeeMap">
<id column="empno" property="empno"/>
<result column="ename" property="ename"/>
<result column="email" property="email"/>
<result column="emobile" property="emobile"/>
<result column="deptno" property="deptno"/>
<result column="sex" property="sex"/>
<result column="dname" property="dname"/>
<result column="location" property="location"/>
<association property="department" javaType="mybatis.entities.Department" column="deptno">
<id column="deptno" property="deptno"/>
<result column="dname" property="dname"/>
<result column="location" property="location"/>
association>
resultMap>
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">
<!-- namespace:指明当前mapper需要映射的dao接口的全类名 -->
<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:设置1：N的联级检索
property:是1一端中定义多一端集合变量名 private List<Employee> emps;
ofType:多一端的具体类型
column:关联列
select：关联其他的<select>
-->
<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
<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