初识MyBatis

 1 package dao.student;
 2 
 3 /**
 4  * 学生持久层接口
 5  * @author Administrator
 6  */
 7 public interface StudentMapper {
 8     /**
 9      * 获得学生总数
10      */
11     public int getStudentCount();
12 }

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="dao.student.StudentMapper">
6     <select id="getStudentCount" resultType="int">
7         select count(1) from student
8     </select>
9 </mapper>

1 driver=com.mysql.jdbc.Driver
2 url=jdbc:mysql://localhost:3306/mysqldemo?useUnicode=true&characterEncoding=utf-8&useSSL=true
3 user=root
4 password=root

 1 log4j.rootLogger=DEBUG,CONSOLE,file
 2 #log4j.rootLogger=ERROR,ROLLING_FILE
 3 log4j.logger.cn.smbms.dao=debug
 4 log4j.logger.com.ibatis=debug 
 5 log4j.logger.com.ibatis.common.jdbc.SimpleDataSource=debug 
 6 log4j.logger.com.ibatis.common.jdbc.ScriptRunner=debug 
 7 log4j.logger.com.ibatis.sqlmap.engine.impl.SqlMapClientDelegate=debug 
 8 log4j.logger.java.sql.Connection=debug 
 9 log4j.logger.java.sql.Statement=debug 
10 log4j.logger.java.sql.PreparedStatement=debug 
11 log4j.logger.java.sql.ResultSet=debug 
12 log4j.logger.org.tuckey.web.filters.urlrewrite.UrlRewriteFilter=debug
13 
14 ######################################################################################
15 # Console Appender  \u65e5\u5fd7\u5728\u63a7\u5236\u8f93\u51fa\u914d\u7f6e
16 ######################################################################################
17 log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
18 log4j.appender.Threshold=error
19 log4j.appender.CONSOLE.Target=System.out
20 log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
21 log4j.appender.CONSOLE.layout.ConversionPattern= [%p] %d %c - %m%n
22 
23 
24 ######################################################################################
25 # DailyRolling File  \u6bcf\u5929\u4ea7\u751f\u4e00\u4e2a\u65e5\u5fd7\u6587\u4ef6\uff0c\u6587\u4ef6\u540d\u683c\u5f0f:log2009-09-11
26 ######################################################################################
27 log4j.appender.file=org.apache.log4j.DailyRollingFileAppender
28 log4j.appender.file.DatePattern=yyyy-MM-dd
29 log4j.appender.file.File=log.log
30 log4j.appender.file.Append=true
31 log4j.appender.file.Threshold=error
32 log4j.appender.file.layout=org.apache.log4j.PatternLayout
33 log4j.appender.file.layout.ConversionPattern=%d{yyyy-M-d HH:mm:ss}%x[%5p](%F:%L) %m%n
34 
35 
36 log4j.logger.com.opensymphony.xwork2=error  

 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 
 6 <!-- 通过这个配置文件完成mybatis与数据库的连接 -->
 7 <configuration>
 8     <!-- 引入 database.properties 文件-->
 9     <properties resource="database.properties"/>
10     <!-- 配置mybatis的log实现为LOG4J -->
11     <settings>
12         <setting name="logImpl" value="LOG4J" />
13     </settings>
14     <environments default="development">
15         <environment id="development">
16             <!--配置事务管理，采用JDBC的事务管理  -->
17             <transactionManager type="JDBC"></transactionManager>
18             <!-- POOLED:mybatis自带的数据源，JNDI:基于tomcat的数据源 -->
19             <dataSource type="POOLED">
20                 <property name="driver" value="${driver}"/>
21                 <property name="url" value="${url}"/>
22                 <property name="username" value="${user}"/>
23                 <property name="password" value="${password}"/>
24             </dataSource>
25         </environment>
26     </environments>
27     <!-- 将mapper文件加入到配置文件中 -->
28     <mappers>
29         <mapper resource="dao/student/StudentMapper.xml"/>
30     </mappers>
31 </configuration>

 1 package dao.student;
 2 
 3 import org.apache.ibatis.session.SqlSession;
 4 import org.apache.log4j.Logger;
 5 import org.junit.Before;
 6 import org.junit.Test;
 7 
 8 import util.SqlSessionUtil;
 9 
10 public class StudentMapperTest {
11     private Logger log = Logger.getLogger(StudentMapperTest.class);
12     @Before
13     public void setUp() throws Exception {
14     }
15 
16     @Test
17     public void test() {
18         SqlSession sqlsession = null;
19         try {
20             sqlsession = SqlSessionUtil.getSqlSession();
21             log.debug(sqlsession.getMapper(StudentMapper.class).getStudentCount());
22         } catch (Exception e) {
23             e.printStackTrace();
24         } finally {
25             SqlSessionUtil.closeSqlSession(sqlsession);
26         }
27     }
28 }

 1 package util;
 2 
 3 import java.io.IOException;
 4 
 5 import org.apache.ibatis.io.Resources;
 6 import org.apache.ibatis.session.SqlSession;
 7 import org.apache.ibatis.session.SqlSessionFactory;
 8 import org.apache.ibatis.session.SqlSessionFactoryBuilder;
 9 
10 public class SqlSessionUtil {
11     private SqlSessionUtil() {
12     }
13     private static SqlSessionFactory sqlsession = null;
14     
15     static {
16         try {
17             sqlsession = new SqlSessionFactoryBuilder().build(Resources.getResourceAsReader("mybatis-config.xml"));
18         } catch (IOException e) {
19             e.printStackTrace();
20         }
21     }
22     
23     public static SqlSession getSqlSession() {
24         return sqlsession.openSession();
25     }
26     
27     public static void closeSqlSession(SqlSession sqlsession) {
28         sqlsession.close();
29     }
30 }