一个简单例子，以及基于接口，class对象调用

应用结构：



IbatisConfiguration.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/ibatis" />
<property name="username" value="root" />
<property name="password" value="" />
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="pojo/Account.xml" />
</mappers>
</configuration>

Account.java

package pojo;

public class Account {
private int id;
private String username;

public int getId() {
return id;
}

public void setId(int id) {
this.id = id;
}

public String getUsername() {
return username;
}

public void setUsername(String username) {
this.username = username;
}

}

Account.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">
<mapper namespace="liyixing">
<select id="getAccount" parameterType="string" resultType="pojo.Account">
select * from Account where username = #{username}
</select>
</mapper>

test.java

package test;

import java.io.IOException;
import java.io.Reader;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

import pojo.Account;

public class Test {

/**
* @param args
*/
public static void main(String[] args) {
try {
Reader reader = Resources
.getResourceAsReader("test/IbatisConfiguration.xml");
SqlSessionFactory sqlMapper = new SqlSessionFactoryBuilder()
.build(reader);

Account account = (Account) sqlMapper.openSession().selectOne(
"liyixing.getAccount", "liyixing");

System.out.println("id: " + account.getId());
System.out.println("name: " + account.getUsername());
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}

}

基于接口，class调用
上面例子中进行修改，首先添加dao类

package dao;

import pojo.Account;

public interface AccountDao {
public Account getAccount(String name);
}

修改映射文件
<?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="dao.AccountDao">
<select id="getAccount" parameterType="string" resultType="pojo.Account">
select * from Account where username = #{username}
</select>
</mapper>
可以看到，首先要改mapper的namespace值，该值和dao接口的包名完全相同。其次是看接口中的方法名，方法名必须在map文件中，存在相同的id才行，否则会报错。这种方式可以将dao接口的实现转移到配置文件中。

修改test类
package test;

import java.io.IOException;
import java.io.Reader;

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 dao.AccountDao;

import pojo.Account;

public class Test {

/**
* @param args
*/
public static void main(String[] args) {
try {
Reader reader = Resources
.getResourceAsReader("test/IbatisConfiguration.xml");
SqlSessionFactory sqlMapper = new SqlSessionFactoryBuilder()
.build(reader);
SqlSession session = sqlMapper.openSession();
AccountDao accountDao = session.getMapper(AccountDao.class);
Account account = accountDao.getAccount("liyixing");

System.out.println("id: " + account.getId());
System.out.println("name: " + account.getUsername());
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
这里通过AccountDao accountDao = session.getMapper(AccountDao.class);方式获取dao接口的实现。这个实现是ibatis帮助创建的。我们只需要生成对应的配置文件即可。

Account account = accountDao.getAccount("liyixing");
通过调用dao接口的方法，进行数据操作。