<?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>
	
	<!-- 读取数据连接参数 -->
	<properties resource="resources/config.properties" />


	<settings>
		<setting name="cacheEnabled" value=http://www.mamicode.com/"true" />>
CustomerMapper.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="model.Customer">


	<resultMap id="customerResultMap" type="model.Customer">
		<id property="id" column="id" />
		<result property="name" column="username" />
		<result property="age" column="age" />
		<result property="des" column="des" />
	</resultMap>






	<!-- 用来定义可重用的 SQL 代码段,可以包含在其他语句中。 -->
	<sql id="customerColumns"> name,age,des </sql>
	<select id="selectCustomerAll3" resultType="Customer">
		select
		<include refid="customerColumns" />
		from customers
	</select>


	<!-- useGeneratedKey ( 仅 对 insert, update 有 用 ) 这 会 告 诉 MyBatis 使 用 JDBC 
		的 getGeneratedKeys 方法来取出由数据 (比如:像 MySQL 和 SQL Server 这样的数据库管理系统的自动递增字段)内部生成的主键。 
		默认值:false。 <selectKey keyProperty="id" resultType="int" order="BEFORE"> select 
		CAST(RANDOM()*1000000 as INTEGER) a from SYSIBM.SYSDUMMY1 </selectKey> #{property,javaType=int,jdbcType=NUMERIC} 
		ORDER BY ${columnName} 这里 MyBatis 不会修改或转义字符串。 -->
	<insert id="saveCustomer" parameterType="model.Customer"
		useGeneratedKeys="true" keyProperty="id" flushCache="true">
		insert into
		customers(name,age,des) values (#{name}, #{age}, #{des})
	</insert>


	<select id="selectCustomerAll" resultType="Customer" flushCache="false" useCache="true">
		select id,name,age,des
		from customers
	</select>
	
	<!--   
		数组 ：
		<foreach item="item" index="index" collection="array" open="(" separator="," close=")">  
		 	#{item}  
		</foreach> 
	-->
	<select id="selectCustomer3" resultType="Customer">
		SELECT id,name,age,des
		FROM customers
		WHERE id in
		<foreach item="item" index="index" collection="list" open="(" separator="," close=")">
			#{id}
		</foreach>
	</select>


	<select id="selectCustomerByBind" parameterType="Customer" resultType="Customer">
		<!-- <bind name="pattern" value=http://www.mamicode.com/"'%' + ${name} + '%'" />  此未测试成功 -->>
Customer.java
package model;


public class Customer {
	
	public int id;
	public String name;
	public int age;
	public String des;


	public Customer() {
	}


	public Customer(int id, String name, int age, String des) {
		this.id = id;
		this.name = name;
		this.age = age;
		this.des = des;
	}
	
	public Customer(String name, int age, String des) {
		this.name = name;
		this.age = age;
		this.des = des;
	}
	
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}


	public int getAge() {
		return age;
	}


	public void setAge(int age) {
		this.age = age;
	}


	public String getDes() {
		return des;
	}
	public void setDes(String des) {
		this.des = des;
	}
	@Override
	public String toString() {
		return "Customer [id=" + id + ", name=" + name + ", age=" + age
				+ ", des=" + des + "]";
	}
	
}

SessionFactoryUtil.java
package dao;


import java.io.IOException;
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;


public class SessionFactoryUtil {
	
	private static final String MYBATIS_CONFIG_PATH = "resources/mybatis-config.xml";
	
	private static InputStream is = null;
	
	private static SqlSessionFactory sqlSessionFactory = null;
	
	static {
		try {
			is = Resources.getResourceAsStream(MYBATIS_CONFIG_PATH);
			//SqlSessionFactoryBuilder这个类可以被实例化,使用和丢弃。一旦创建了 SqlSessionFactory 后,这个类就不需 要存在了。 
			//因此 SqlSessionFactoryBuilder 实例的最佳范围是方法范围 (也就是本地方法变量)。
			sqlSessionFactory = new SqlSessionFactoryBuilder().build(is); 
		} catch (IOException e) {
			e.printStackTrace();
		}
		
	}
	/**
	 * 私有构造器
	 */
	private SessionFactoryUtil(){};
	
	/**
	 *  SqlSessionFactory 的最佳实践是在应用运行期间不要重复创建多次
	 *  最简单的就是使用单例模式或者静态单例模式。
	 * @return SqlSessionFactory
	 */
	public static SqlSessionFactory getSqlSessionFactoryIntance(){
		
		return sqlSessionFactory;
		
	}
	
	/**
	 * 每个线程都应该有它自己的 SqlSession 实例。
	 * SqlSession 的实例不能被共享,也是线程 不安全的。
	 * 因此最佳的范围是请求或方法范围。
	 * 绝对不能将 SqlSession 实例的引用放在一个 类的静态字段甚至是实例字段中。
	 * @return SqlSession
	 */
	public static SqlSession getSqlSessionIntance() {


		return sqlSessionFactory.openSession();
		
	}
	
}

测试：
package dao;


import java.util.ArrayList;
import java.util.List;
import java.util.Map;


import model.Customer;


import org.apache.ibatis.session.SqlSession;
import org.junit.Test;


public class CustomerDao {


	public CustomerDao() {
	}


	@Test
	public void findCustomer() {


		//SqlSessionFactory ssf = null;
		SqlSession sqlSession = null;
		try {
			//ssf = SessionFactoryUtil.getSqlSessionFactoryIntance();
			sqlSession = SessionFactoryUtil.getSqlSessionIntance();
			System.out.println(sqlSession); //每次都是新建一个SqlSession实例org.apache.ibatis.session.defaults.DefaultSqlSession@dc57db
			
			//sqlSession = SessionFactoryUtil.getSqlSessionIntance();
			//System.out.println(sqlSession); //每次都是新建一个SqlSession实例org.apache.ibatis.session.defaults.DefaultSqlSession@c24c0
			
			//resultType="hashmap"  返回类型为 Map<id,Map<列名，值>>
			Map<Object, Object> customerMap = (Map<Object, Object>) sqlSession.selectMap("selectCustomerAll2", "id");
			System.out.println("customerMap : " + customerMap);
			for(Map.Entry<Object, Object> customerSingle : customerMap.entrySet()) {
				System.out.println("customerMap : " + customerSingle);
				System.out.println("customerMap_Key : " + customerSingle.getKey());
				System.out.println("customerMap_Value : " + customerSingle.getValue());
				@SuppressWarnings("unchecked")
				Map<Object, Object> map = (Map<Object, Object>) customerSingle.getValue();
				System.out.println("Name : " + map.get("name"));
			}
			
			//resultType="Customer" 自动封装成 list
			//如果没有查到数据，返回长度为0的list
			//List<Customer> customerList = sqlSession.selectList("selectCustomerAll");
			
			//测试 bind 用于  like 查询
			Customer customerBind = new Customer("Man",110,"service");
			List<Customer> customerList = sqlSession.selectList("selectCustomerByBind", customerBind);

			System.out.println("customerList : " + customerList);
			System.out.println("customerList : " + customerList.size());
			
			List<Customer> customerList1 = new ArrayList<Customer>();
			System.out.println("customerList1 : " + customerList1);
			System.out.println("customerList1 : " + customerList1.size());
			
			for (Customer customer : customerList) {
				System.out.println(customer);
			}
			
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			if(sqlSession != null) {
				sqlSession.close();
			}
		}


	}


	@Test
	public void saveCustomer() {
		
		SqlSession sqlSession = null;
		try {
			sqlSession = SessionFactoryUtil.getSqlSessionIntance();
			
			Customer customer = new Customer("herry",110,"service");
			int id = sqlSession.insert("saveCustomer", customer); //返回影响的行数
			System.out.println(id);
			System.out.println(customer.getId()); //id 已经被set为 自增长的 key
			
			sqlSession.commit();
		} catch (Exception e) {
			e.printStackTrace();
			sqlSession.rollback();
		}finally {
			sqlSession.close();
		}
	}
}