Ibatis 实现 一对一 关联

习惯了Hibernate 一到公司,居然是Hibernate和Ibatis都在用..

 

没办法,开始学了...从最简单的一对一关系的映射开始(奉劝初学JavaEE的朋友,不要太依赖MyEclipse,我的教训啊..)

 

Ibatis 是一种java的持久层框架,映射文件的配置是基于Sql语句的,虽然配置比Hibernate复杂,但是会更灵活一些,效率也会高

 

1.创建实体类,跟Hibernate是一样的,相互做一对一的成员对象

public class User {
	private int userid;
	private String username;
	private String password;
	private UserInfo info;
}
public class UserInfo {
	private int userinfoid;
	private String email;
	private String qq;
	private User user;
	private int userid;
}

 

 

记得添加setter 和 getter

2.创建Ibatis的配置文件

 

之前还要引入Ibatis的jar包 这里采用的是2.3.4版本的,3.0以上的跟2.x的区别很大

 

配置文件的DTD

<!DOCTYPE sqlMapConfig PUBLIC "-//iBATIS.com//DTD SQL Map Config 2.0//E "http://www.ibatis.com/dtd/sql-map-config-2.dtd"> 

 

一个简单的配置文件:

<?xml version="1.0" encoding="UTF-8"?> 
<!DOCTYPE sqlMapConfig
  PUBLIC "-//iBATIS.com//DTD SQL Map Config 2.0//EN"
  "http://www.ibatis.com/dtd/sql-map-config-2.dtd">
<sqlMapConfig>
	<!-- 常用属性的配置  -->
	<settings cacheModelsEnabled="true" enhancementEnabled="true"
		lazyLoadingEnabled="true" maxRequests="32" maxSessions="10"
		maxTransactions="5" useStatementNamespaces="false" />
	<transactionManager type="JDBC">
		<!-- 配置数据源 -->
		<dataSource type="SIMPLE">
			<!-- 驱动的设置 -->
			<property name="JDBC.Driver" value="com.mysql.jdbc.Driver" />
			<!-- 数据库url的设置 -->
			<property name="JDBC.ConnectionURL" value="jdbc:mysql://localhost:3306/test" />
			<!-- 数据库用户名的设置 -->
			<property name="JDBC.Username" value="root" />
			<!-- 数据库密码的设置 -->
			<property name="JDBC.Password" value="" />
		</dataSource>
	</transactionManager>
	<!-- 映射文件的列表 -->
	<sqlMap resource="jpo/ibatis/test/o2o/user.sqlmap.xml" />
</sqlMapConfig>

 

映射文件的配置

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE sqlMap
PUBLIC "-//iBATIS.com//DTD SQL Map 2.0//EN"
"http://www.ibatis.com/dtd/sql-map-2.dtd">
<sqlMap namespace="test">
	<!--为两个类设置映射文件-->
	<typeAlias alias="user" type="jpo.ibatis.test.o2o.User" />
	<typeAlias alias="userinfo" type="jpo.ibatis.test.o2o.UserInfo" />
	<!--针对结果集的结果映射-->
	<resultMap id="iuser" class="user">
		<result property="userid" column="userid" />
		<result property="username" column="username" />
		<result property="password" column="password" />
		<!--得到User的时候,希望Ibatis为我同时取得UserInfo对象,并设置好 -->
		<result property="info" column="userid" select="getUserInfoByUserId" />
	</resultMap>
	<resultMap id="iuserinfo" class="userinfo">
		<result property="userinfoid" column="userinfoid" />
		<result property="userid" column="userid" />
		<result property="email" column="email" />
		<result property="qq" column="qq" />
	</resultMap>
	<!--一个查询,也可以是insert update 只需设置好对应的sql语句即可-->
	<select id="getUserInfoByUserId" parameterClass="int" resultMap="iuserinfo">
		select * from
		userinfo
		where userid=#userid#
    </select>

	<select id="getUserByUserId" parameterClass="int" resultMap="iuser">
		select * from
		user
		where userid=#userid#
    </select>
</sqlMap>

  测试类:

 

	public static void main(String[] args) throws SQLException {
		Reader reader = null;
		try {
			reader = new InputStreamReader(new FileInputStream("src/jpo/ibatis/test/o2o/ibatis-config.xml"));
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		}
		SqlMapClient client = SqlMapClientBuilder.buildSqlMapClient(reader);

		try {
			reader.close();
		} catch (IOException e) {
			e.printStackTrace();
		}

		User user = (User) client.queryForObject("getUserByUserId", 1);

		System.out.println(user.getUsername());

		UserInfo info = user.getInfo();

		System.out.println(info.getEmail());
		System.out.println("done...");

	}

 

 

这是一个ibatis的HelloWorld程序