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MyBatis从入门到放弃一：从SqlSession实现增删改查
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前言
开博客这是第一次写系列文章，从内心上讲是有点担心自己写不好，写不全，毕竟是作为java/mybatis学习的过程想把学习的路线和遇到的问题都总结下来，也让知识点在脑海里能形成一个体系。
开发环境
idea2016、mybatis3、SQLServer2012
pom.xml、mybatis.xml、log4j.properties
先贴上pom.xml是因为他直接和搭建开发环境和测试环境有关系，mybatis.xml则是连接数据库，log4j.properties在学习阶段配置上有助于我们观察SQL的执行情况。
1、pom.xml
<dependencies>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.4.2</version>
</dependency>
<dependency>
<groupId>com.microsoft.sqlserver</groupId>
<artifactId>sqljdbc4</artifactId>
<version>4.0</version>
</dependency>
<dependency>
<groupId>commons-dbcp</groupId>
<artifactId>commons-dbcp</artifactId>
<version>1.4</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.10</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
</dependencies>
2、mybatis.xml
<?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> <!-- MyBatis针对SqlServer进行的配置 -->
<typeAliases>
<typeAlias alias="User" type="com.autohome.model.User"/>
<typeAlias alias="Teacher" type="com.autohome.model.Teacher" />
<typeAlias alias="Student" type="com.autohome.model.Student" />
</typeAliases>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="com.microsoft.sqlserver.jdbc.SQLServerDriver"/>
<property name="url" value="jdbc:sqlserver://localhost:1433;DatabaseName=test"/>
<property name="username" value="sa"/>
<property name="password" value="0"/>
</dataSource>
</environment>
</environments> <mappers>
<mapper resource="mapper/User.xml"/>
<mapper resource="mapper/Student.xml"/>
</mappers>
</configuration>
3、log4j.properties
### Log4j配置 ###
### 与Spring结合需要在web.xml中指定此文件位置，并添加监听器 ###
#定义log4j的输出级别和输出目的地（目的地可以自定义名称，和后面的对应）
#[ level ] , appenderName1 , appenderName2
log4j.rootLogger=DEBUG,console,file #-----------------------------------#
#1 定义日志输出目的地为控制台
log4j.appender.console = org.apache.log4j.ConsoleAppender
log4j.appender.console.Target = System.out
log4j.appender.console.Threshold=DEBUG
####可以灵活地指定日志输出格式，下面一行是指定具体的格式 ###
#%c: 输出日志信息所属的类目，通常就是所在类的全名
#%m: 输出代码中指定的消息,产生的日志具体信息
#%n: 输出一个回车换行符，Windows平台为"/r/n"，Unix平台为"/n"输出日志信息换行
log4j.appender.console.layout = org.apache.log4j.PatternLayout
log4j.appender.console.layout.ConversionPattern=[%c]-%m%n #-----------------------------------#
#2 文件大小到达指定尺寸的时候产生一个新的文件
log4j.appender.file = org.apache.log4j.RollingFileAppender
#日志文件输出目录
log4j.appender.file.File=log/tibet.log
#定义文件最大大小
log4j.appender.file.MaxFileSize=10mb
###输出日志信息###
#最低级别
log4j.appender.file.Threshold=ERROR
log4j.appender.file.layout=org.apache.log4j.PatternLayout
log4j.appender.file.layout.ConversionPattern=[%p][%d{yy-MM-dd}][%c]%m%n #-----------------------------------#
#3 druid
log4j.logger.druid.sql=INFO
log4j.logger.druid.sql.DataSource=info
log4j.logger.druid.sql.Connection=info
log4j.logger.druid.sql.Statement=info
log4j.logger.druid.sql.ResultSet=info #4 mybatis 显示SQL语句部分
log4j.logger.org.mybatis=DEBUG
#log4j.logger.cn.tibet.cas.dao=DEBUG
#log4j.logger.org.mybatis.common.jdbc.SimpleDataSource=DEBUG#
#log4j.logger.org.mybatis.common.jdbc.ScriptRunner=DEBUG#
#log4j.logger.org.mybatis.sqlmap.engine.impl.SqlMapClientDelegate=DEBUG#
#log4j.logger.java.sql.Connection=DEBUG
log4j.logger.java.sql=DEBUG
log4j.logger.java.sql.Statement=DEBUG
log4j.logger.java.sql.ResultSet=DEBUG
log4j.logger.java.sql.PreparedStatement=DEBUG
配置mapper.xml
mapper.xml在mybatis.xml是专职处理sql的一个环节，各种映射和实现都在这里处理
<?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.autohome.mapper.User"> <!-- 查询全部用户 -->
<select id="queryUsers" resultType="com.autohome.model.User">
select * from t_userinfo
</select>
<!-- 按照ID查询 -->
<select id="queryUserById" parameterType="int" resultType="com.autohome.model.User">
select * from t_userinfo where id=#{id}
</select> <select id="queryUserByAddress" resultType="com.autohome.model.User">
select * from t_userinfo where name=#{name,javaType=String,jdbcType=VARCHAR} and address=#{address}
</select> <!-- 添加用户 -->
<insert id="insertUsers" parameterType="com.autohome.model.User">
insert into t_userinfo (name,address) values(#{name},#{address})
</insert>
<!-- 修改用户 -->
<update id="updateUsers" parameterType="com.autohome.model.User">
update t_userinfo set name=#{name},address=#{address} where id=#{id}
</update>
<!-- 删除用户 -->
<delete id="deleteUsers" parameterType="int">
delete t_userinfo where id=#{id}
</delete>
</mapper>
建立单元测试
1、准备工作，我建立的是控制台程序，所以在使用sqlsession前先创建sqlsessionfactory。当然，还要加载log4j.properties
SqlSessionFactory sqlSessionFactory=null;
@Before
public void BeforeClass(){ try {
InputStream is=Resources.getResourceAsStream("log4j.properties");
PropertyConfigurator.configure(is);
Reader reader = Resources.getResourceAsReader("mybatis.xml");
sqlSessionFactory= new SqlSessionFactoryBuilder().build(reader);
} catch (IOException e) {
e.printStackTrace();
} }
2、queryUsers
@Test
public void queryUsers() throws Exception { //线程不安全类型，放在方法体内
SqlSession sqlSession=null; try { sqlSession=sqlSessionFactory.openSession(); List<User> list = sqlSession.selectList("com.autohome.mapper.User.queryUsers");
System.out.println("size:"+list.size()); } catch (Exception e) {
e.printStackTrace();
}finally {
sqlSession.close();
} }
3、queryUserById
@Test
public void queryUserById() {
SqlSession sqlSession=null;
try{
sqlSession=sqlSessionFactory.openSession(); User user = sqlSession.selectOne("com.autohome.mapper.User.queryUserById",2);
System.out.println("id:"+user.getId()+",name:"+user.getName()+","+user.getAddress());
}catch(Exception e){
e.printStackTrace();
}finally {
sqlSession.close();
}
}
4、insertUser
@Test
public void insertUser(){ SqlSession sqlSession=null;
try{ sqlSession=sqlSessionFactory.openSession(); User user =new User();
user.setName("kobe");
user.setAddress("usa"); int result = sqlSession.insert("com.autohome.mapper.User.insertUsers",user);
sqlSession.commit();
if(result>0){
System.out.println("insert success....");
}else{
System.out.println("insert error....");
} }catch(Exception e){
e.printStackTrace();
}finally {
sqlSession.close();
} }
5、updateUser
@Test
public void updateUser(){
SqlSession sqlSession=null;
try{ sqlSession=sqlSessionFactory.openSession(); User user =new User();
user.setId(36);
user.setName("kobe");
user.setAddress("usa"); int result = sqlSession.update("com.autohome.mapper.User.updateUsers",user);
sqlSession.commit();
if(result>0){
System.out.println("update success....");
}else{
System.out.println("update error....");
} }catch(Exception e){
e.printStackTrace();
}finally {
sqlSession.close();
}
}
6、deleteUser
@Test
public void deleteUser(){
SqlSession sqlSession=null;
try{ sqlSession=sqlSessionFactory.openSession(); int result = sqlSession.delete("com.autohome.mapper.User.deleteUsers",49);
sqlSession.commit();
if(result>0){
System.out.println("delete success....");
}else{
System.out.println("delete error....");
} }catch(Exception e){
e.printStackTrace();
}finally {
sqlSession.close();
}
}
总结
添加、修改、删除的操作要调用sqlsession.commit(),不然数据无法入库的，我刚开始就忘记了这个。
