在UserMapper.xml中添加增删改查
<?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">
<!-- 如果我要调用mapper文件，就去拿到namespace+id(方法名)的名字就可以访问 -->
<mapper namespace="cn.bdqn.dao.UserMapper">
<!-- id要唯一的，一般是下拉类的方法名 -->
<!-- 返回的是什么类型int -->
<select id="count" resultType="int">
select count(1) from user
</select>
<!-- 增加 -->
<insert id="add" parameterType="User">
insert into user(userCode,userName,userPassword)
values (#{userCode},#{userName},#{userPassword})
</insert>
<!-- 修改 -->
<update id="update" parameterType="User">
update user set userCode=#{userCode},userName=#{userName},
userPassword=#{userPassword} where id=#{id}
</update>
<!-- 删除 -->
<delete id="delete" parameterType="User">
delete from user where id=#{id}
</delete>
<!-- 查询 -->
<select id="getUserList" resultType="User">
select * from user
</select>
</mapper>
同时加上mybatis-config.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"> <!-- 通过这个配置文件完成mybatis与数据库的连接 -->
<configuration>
<!-- 引入 jdbc.properties 文件-->
<properties resource="jdbc.properties"/>
<!-- alias别名 -->
<typeAliases>
<!-- <typeAlias type="cn.bdqn.pojo.User" alias="User"/> -->
<!-- 用这个比较方便，不用一个一个写。包下的就是他的类名 -->
<package name="cn.bdqn.pojo"/>
</typeAliases> <environments default="development">
<environment id="development">
<!--配置事务管理，采用JDBC的事务管理 -->
<transactionManager type="JDBC"></transactionManager>
<!-- POOLED:mybatis自带的数据源，JNDI:基于tomcat的数据源 -->
<dataSource type="POOLED">
<property name="driver" value="${driver}"/>
<property name="url" value="${url}"/>
<property name="username" value="${username}"/>
<property name="password" value="${password}"/>
</dataSource>
</environment>
</environments> <!-- 将mapper文件加入到配置文件中 将来mapper文件很多所以是mappers -->
<mappers>
<mapper resource="cn/bdqn/dao/UserMapper.xml"/>
</mappers>
</configuration>
首先把相同的代码块拿出来封装成一个类MyBatisUtil
public class MyBatisUtil {
private static SqlSessionFactory factory;
/**
* 一般情况下,如果有些代码必须在项目启动的时候就执行的时候,需要使用静态代码块,这种代码是主动执行的;
* 需要在项目启动的时候就初始化,在不创建对象的情况下,其他程序来调用的时候,需要使用静态方法,这种代码是被动执行的.
* 静态方法在类加载的时候 就已经加载 可以用类名直接调用
*/
static{//在静态代码块下，factory只会被创建一次
System.out.println("static factory===============");
try {
InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
factory = new SqlSessionFactoryBuilder().build(is);
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
//创建sqlSession
public static SqlSession createSqlSession(){
return factory.openSession();
}
//关闭资源
public static void closeSqlSession(SqlSession sqlSession){
if(null != sqlSession)
sqlSession.close();
}
}接下来实现增删改查就很简单了----->注意：（增删改一定要记住在后面加commit()）
public class UserDaoTest {
private Logger logger = Logger.getLogger(UserDaoTest.class);
//count
@Test
public void countTest() {
SqlSession sqlSession = null;
int count = 0;
try {
sqlSession = MyBatisUtil.createSqlSession();
count = sqlSession.selectOne("cn.bdqn.dao.UserMapper.count");
logger.debug("count==="+count);
} catch (Exception e) {
// TODO: handle exception
sqlSession.rollback();
}finally{
MyBatisUtil.closeSqlSession(sqlSession);
}
}
//add
@Test
public void addTest(){
SqlSession sqlSession = null;
try {
User user = new User();
user.setUserCode("aaaa");
user.setUserName("bbbbb");
sqlSession = MyBatisUtil.createSqlSession();
sqlSession.insert("cn.bdqn.dao.UserMapper.add",user);
sqlSession.commit();
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
sqlSession.rollback();
}finally{
MyBatisUtil.closeSqlSession(sqlSession);
}
}
//修改
@Test
public void updateTest(){
SqlSession sqlSession = null;
try {
User user = new User();
user.setId(12);
user.setUserCode("改1111");
user.setUserName("改2222");
sqlSession = MyBatisUtil.createSqlSession();
sqlSession.update("cn.bdqn.dao.UserMapper.update",user);
sqlSession.commit();
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
sqlSession.rollback();
}finally{
MyBatisUtil.closeSqlSession(sqlSession);
}
}
//删除
@Test
public void deleteTest(){
SqlSession sqlSession = null;
try {
User user = new User();
user.setId(12);
sqlSession = MyBatisUtil.createSqlSession();
sqlSession.delete("cn.bdqn.dao.UserMapper.delete",user);
sqlSession.commit();
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
sqlSession.rollback();
}finally{
MyBatisUtil.closeSqlSession(sqlSession);
}
}
}//查询
@Test
public void getUserListTest(){
SqlSession sqlSession = null;
try {
List<User> userList = new ArrayList<User>();
sqlSession = MyBatisUtil.createSqlSession();
userList = sqlSession.selectList("cn.bdqn.dao.UserMapper.getUserList");
for(User user:userList){
logger.debug("user的id==="+user.getId());
}
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
sqlSession.rollback();
}finally{
MyBatisUtil.closeSqlSession(sqlSession);
}
}