接着上面创建的maven项目来。
1.java目录下创建cn.happy.entity包
2.idea下创建数据库连接
配置连接参数
3.把数据库表变成实体类
导入成功，改一下包名就可以用了
4.新建cn.happy.dao包，在下面新建IUserDAO接口，代码如下
1 package cn.happy.dao;
2
3 import cn.happy.entity.Smbms_user;
4
5 import java.util.List;
6
7 public interface IUserDAO {
8 List<Smbms_user> findAll();
9 }
5.在IUserDAO同包下新建IUserDAO.xml文件（俗称小配置），文件名一定要相同（这样做可以规避后面的一些问题）。
官方文档中找到
2.1.4 Exploring Mapped SQL Statements
把下面的文档直接粘贴到IUserDAO.xml里
1 <?xml version="1.0" encoding="UTF-8" ?>
2 <!DOCTYPE mapper
3 PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
4 "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
5 <mapper namespace="org.mybatis.example.BlogMapper">
6 <select id="selectBlog" parameterType="int" resultType="Blog">
7 select * from Blog where id = #{id}
8 </select>
9 </mapper>
修改包名和<mapper>节点，比如我的代码修改如下即可
1 <?xml version="1.0" encoding="UTF-8" ?> 2 <!DOCTYPE mapper 3 PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" 4 "http://mybatis.org/dtd/mybatis-3-mapper.dtd"> 5 <!--关联接口的全限定名--> 6 <mapper namespace="cn.happy.dao.IUserDAO"> 7 <!--大配置中settings autoMappingBehavior NONE,所以数据库只会装配以下column--> 8 <resultMap id="UserMapper" type="cn.happy.entity.Smbms_user"> 9 <id property="id" column="id"/> 10 <result property="username" column="username"/> 11 <result property="userpassword" column="userpassword"/> 12 </resultMap> 13 <!--id要与接口中的方法名相同--> 14 <select id="findAll" resultMap="UserMapper"> 15 select * from smbms_user 16 </select> 17 </mapper>
6.配置resources
这里需要配置三个文件
1.jdbc.properties
2.log4j.properties
3.mybatis-config.xml
jdbc.properties
1 jdbc.driver=com.mysql.jdbc.Driver 2 jdbc.url=jdbc:mysql:///t14_smbms?characterEncoding=utf8&useSSL=true 3 jdbc.username=root 4 jdbc.password=root
log4j.properties
1 log4j.rootLogger=debug,stdout,file
2 ### direct log messages to stdout ###
3 log4j.appender.stdout=org.apache.log4j.ConsoleAppender
4 log4j.appender.stdout.Target=System.out
5 log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
6 log4j.appender.stdout.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n
7
8 ### direct messages to file mylog.log ###
9 log4j.appender.file=org.apache.log4j.FileAppender
10 log4j.appender.file.File=c:\\logs\\log.log
11 log4j.appender.file.layout=org.apache.log4j.PatternLayout
12 log4j.appender.file.layout.ConversionPattern=%d{ABSOLUTE} %5p %c{1}:%L - %m%n
13
14 ### set log levels - for more verbose logging change ‘info‘ to ‘debug‘ ###
15
16 log4j.logger.cn.happy.dao=debug, stdout,file
mybatis-config.xml,俗称大配置
1 <?xml version="1.0" encoding="UTF-8" ?>
2 <!DOCTYPE configuration
3 PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
4 "http://mybatis.org/dtd/mybatis-3-config.dtd">
5 <configuration>
6 <!--引入 jdbc.properties-->
7 <properties resource="jdbc.properties"/>
8 <settings>
9 <setting name="logImpl" value="LOG4J"/>
10 <setting name="autoMappingBehavior" value="NONE"/>
11 </settings>
12 <!--别名，这里不使用别名，一律使用全限定名-->
13 <!--<typeAliases>
14 <package name="cn.happy.entity"/>
15 </typeAliases>-->
16 <!--DB connection info,配置mybatis多套运行环境-->
17 <environments default="development">
18 <environment id="development">
19 <!--采用jdbc事务管理-->
20 <transactionManager type="JDBC"/>
21 <dataSource type="POOLED">
22 <property name="driver" value="${jdbc.driver}"/>
23 <property name="url" value="${jdbc.url}"/>
24 <property name="username" value="${jdbc.username}"/>
25 <property name="password" value="${jdbc.password}"/>
26 </dataSource>
27 </environment>
28 </environments>
29 <!--大配置关联小配置-->
30 <mappers>
31 <!--关联单个小配置,不能重复关联-->
32 <mapper resource="cn/happy/dao/IUserDAO.xml"/>
33 <!--关联整个包,dao层接口名字和对应的xml名字要一样-->
34 <!--<package name="cn.happy.dao"/>-->
35 </mappers>
36 </configuration>
7.编写MyBatisUtil类
1 package cn.happy.util;
2
3 import org.apache.ibatis.io.Resources;
4 import org.apache.ibatis.session.SqlSession;
5 import org.apache.ibatis.session.SqlSessionFactory;
6 import org.apache.ibatis.session.SqlSessionFactoryBuilder;
7
8 import java.io.IOException;
9 import java.io.InputStream;
10
11 public class MyBatisUtil {
12 private static InputStream is;
13 private static SqlSessionFactory sqlSessionFactory;
14 static {
15 try {
16 is=Resources.getResourceAsStream("mybatis-config.xml");
17 } catch (IOException e) {
18 e.printStackTrace();
19 }
20 sqlSessionFactory= new SqlSessionFactoryBuilder().build(is);
21 }
22 private MyBatisUtil(){}
23 public static SqlSession getSession(){
24 return sqlSessionFactory.openSession();
25 }
26 }
8.创建测试类
代码：
1 package cn.happy.test;
2
3 import cn.happy.dao.IUserDAO;
4 import cn.happy.entity.Smbms_user;
5 import cn.happy.util.MyBatisUtil;
6 import org.apache.ibatis.session.SqlSession;
7 import org.junit.Test;
8
9 import java.util.List;
10
11 public class Test20170916 {
12 @Test
13 public void findAll(){
14 SqlSession session = MyBatisUtil.getSession();
15 IUserDAO mapper = session.getMapper(IUserDAO.class);
16 List<Smbms_user> users = mapper.findAll();
17 for (Smbms_user user:users
18 ) {
19 System.out.println(user.getId()+"\t"+user.getUsername()+"\t"+user.getUserpassword());
20 }
21 }
22 }
运行结果：
时间： 2024-08-03 17:57:06