这里是最基本的搭建：http://www.cnblogs.com/xuyiqing/p/8600888.html
接下来做到了简单的增删改查：http://www.cnblogs.com/xuyiqing/p/8601506.html
但是发现代码重复过多等问题
接下来整合并实现DAO开发：
一：原始DAO开发：
package dao;
import pojo.User;
public interface UserDao {
public User selectUserById(Integer id);
}
package dao; import java.util.List;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory; import pojo.User; public class UserDaoImpl implements UserDao { //注入
private SqlSessionFactory sqlSessionFactory;
public UserDaoImpl(SqlSessionFactory sqlSessionFactory) {
this.sqlSessionFactory = sqlSessionFactory;
} //通过用户ID查询一个用户
public User selectUserById(Integer id){
SqlSession sqlSession = sqlSessionFactory.openSession();
return sqlSession.selectOne("test.findUserById", id);
}
//通过用户名称模糊查询
public List<User> selectUserByUsername(Integer id){
SqlSession sqlSession = sqlSessionFactory.openSession();
return sqlSession.selectList("test.findUserById", id);
}
}
测试类：
package junit; import java.io.InputStream; import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Before;
import org.junit.Test; import dao.UserDao;
import dao.UserDaoImpl;
import pojo.User; public class DaoTest {
public SqlSessionFactory sqlSessionFactory;
@Before
public void before() throws Exception {
String resource = "sqlMapConfig.xml";
InputStream in = Resources.getResourceAsStream(resource);
sqlSessionFactory = new SqlSessionFactoryBuilder().build(in);
}
@Test
public void testDao() throws Exception {
UserDao userDao = new UserDaoImpl(sqlSessionFactory);
User user = userDao.selectUserById(10);
System.out.println(user);
}
}
但是还是发现代码重复、浪费资源等问题：
于是想到Mapper动态代理开发：
package mapper;
import pojo.User;
public interface UserMapper {
//遵循四个原则
//接口 方法名 == User.xml 中 id 名
//返回值类型 与 Mapper.xml文件中返回值类型要一致
//方法的入参类型 与Mapper.xml中入参的类型要一致
//命名空间 绑定此接口
//这里如果返回的是一个对象，则调用selectOne方法
//如果是List，则调用selectlist方法
public User findUserById(Integer id);
}
UserMapper.xml
<?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">
<!-- 写Sql语句 -->
<mapper namespace="mapper.UserMapper">
<!-- 通过ID查询一个用户 -->
<select id="findUserById" parameterType="Integer" resultType="pojo.User">
select * from user where id = #{v}
</select> <!-- //根据用户名称模糊查询用户列表
#{} select * from user where id = ？ 占位符 ? == '五'
${} select * from user where username like '%五%' 字符串拼接 -->
<select id="findUserByUsername" parameterType="String" resultType="pojo.User">
select * from user where username like "%"#{haha}"%"
</select> <!-- 添加用户 -->
<insert id="insertUser" parameterType="pojo.User">
<selectKey keyProperty="id" resultType="Integer" order="AFTER">
select LAST_INSERT_ID()
</selectKey>
insert into user (username,birthday,address,sex)
values (#{username},#{birthday},#{address},#{sex})
</insert> <!-- 更新 -->
<update id="updateUserById" parameterType="pojo.User">
update user
set username = #{username},sex = #{sex},birthday = #{birthday},address = #{address}
where id = #{id}
</update> <!-- 删除 -->
<delete id="deleteUserById" parameterType="Integer">
delete from user
where id = #{vvvvv}
</delete> </mapper>
主配置文件sqlMapConfig.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>
<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://localhost:3306/mybatis?characterEncoding=utf-8" />
<property name="username" value="root" />
<property name="password" value="xuyiqing" />
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="mapper/UserMapper.xml"/>
</mappers>
</configuration>
测试类：
package junit;
import java.io.InputStream; import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Test; import mapper.UserMapper;
import pojo.User; public class MybatisMapperTest { @Test
public void testMapper() throws Exception {
String resource = "sqlMapConfig.xml";
InputStream in = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(in);
SqlSession sqlSession = sqlSessionFactory.openSession(); //SqlSession自动为接口生成一个实现类
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
User user = userMapper.findUserById(10);
System.out.println(user);
}
}
通常情况下，建议使用Mapper动态代理开发
配置上还可以完善下：
主配置文件：
<?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>
<properties resource="jdbc.properties"/>
<typeAliases>
<package name="pojo"/>
</typeAliases> <!-- 和spring整合后 environments配置将废除 -->
<environments default="development">
<environment id="development">
<!-- 使用jdbc事务管理 -->
<transactionManager type="JDBC" />
<!-- 数据库连接池 -->
<dataSource type="POOLED">
<property name="driver" value="${jdbc.driver}" />
<property name="url"
value="${jdbc.url}" />
<property name="username" value="${jdbc.username}" />
<property name="password" value="${jdbc.password}" />
</dataSource>
</environment>
</environments> <!--Mapper.xml：写Sql语句的文件的位置 -->
<mappers>
<!-- 这种方式要求包和对应xml文件在一个包中 -->
<package name="mapper"/>
</mappers>
</configuration>
jdbc.properties
jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/mybatis?characterEncoding=utf-8
jdbc.username=root
jdbc.password=xuyiqing
在user.xml中类名就可以简化了：
<?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">
<!-- 写Sql语句 -->
<mapper namespace="mapper.UserMapper">
<!-- 通过ID查询一个用户 -->
<select id="findUserById" parameterType="Integer" resultType="User">
select * from user where id = #{v}
</select> <!-- //根据用户名称模糊查询用户列表
#{} select * from user where id = ？ 占位符 ? == '五'
${} select * from user where username like '%五%' 字符串拼接 -->
<select id="findUserByUsername" parameterType="String" resultType="User">
select * from user where username like "%"#{haha}"%"
</select> <!-- 添加用户 -->
<insert id="insertUser" parameterType="pojo.User">
<selectKey keyProperty="id" resultType="Integer" order="AFTER">
select LAST_INSERT_ID()
</selectKey>
insert into user (username,birthday,address,sex)
values (#{username},#{birthday},#{address},#{sex})
</insert> <!-- 更新 -->
<update id="updateUserById" parameterType="User">
update user
set username = #{username},sex = #{sex},birthday = #{birthday},address = #{address}
where id = #{id}
</update> <!-- 删除 -->
<delete id="deleteUserById" parameterType="Integer">
delete from user
where id = #{vvvvv}
</delete> </mapper>