Java：iBatis简单入门
简介:
jar包
普通的javaBean: domain.User
与bean对应的SQL映射文件: maps/User.xml
iBatis需要的配置文件: SqlMapConfig.xml
加载iBatis配置文件SqlMapConfig.xml是相对于class loader所在目录的相对路径. 如在Web程序中，例如Tomcat下时，class loader所对应的目录是WEB-INF/classes目录. 如在普通的单机运用程序中，class loader对应的目录是编译生成class的bin目录(把src和bin分开存放时).
1. 需要的jar包(暂且先用下面的，可到http://www.javaeye.com/topic/26433示例中一起下载):
commons-dbcp.jar, commons-logging-api.jar, commons-logging.jar, commons-pool.jar,
hsqldb.jar, ibatis-common-2.jar, ibatis-dao-2.jar, ibatis-sqlmap-2.jar,
mysql-connector-java-3.1.12-bin.jar
2. 类User:
package domain;
public class User {
private int id;
private String name;
public User() {}
public User(String name) { this(0, name); }
public User(int id, String name) {
this.id = id;
this.name = name;
}
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; }
@Override
public String toString() { return "ID: " + id + ", Name: " + name; }
}
3. User.xml映射文件:
<?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="User">
<!-- 设置本映射中的别名: 方便使用 -->
<typeAlias alias="user" type="domain.User" />
<typeAlias alias="string" type="java.lang.String" />
<typeAlias alias="integer" type="java.lang.Integer" />
<!-- 增删查改的Statement配置 -->
<select id="getAllUsers" resultClass="user"><![CDATA[
SELECT id, name FROM user ORDER BY id
]]></select>
<select id="getUser" resultClass="user" parameterClass="integer"><![CDATA[
SELECT id, name FROM user WHERE id=#id#
]]></select>
<update id="updateUser" parameterClass="user"><![CDATA[
UPDATE user SET name=#name# WHERE id=#id#
]]></update>
<insert id="insertUser" parameterClass="user"><![CDATA[
INSERT INTO user (name) VALUES (#name#)
]]></insert>
<delete id="deleteUser" parameterClass="integer"><![CDATA[
DELETE FROM user WHERE id=#id#
]]></delete>
</sqlMap>
4. iBatis需要的配置文件:
<?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>
<settings cacheModelsEnabled="true" enhancementEnabled="true"
lazyLoadingEnabled="true" errorTracingEnabled="true" maxRequests="32"
maxSessions="10" maxTransactions="5" useStatementNamespaces="false" />
<transactionManager type="JDBC">
<dataSource type="SIMPLE">
<!-- JDBC连接需要的配置 -->
<property name="JDBC.Driver" value="com.mysql.jdbc.Driver" />
<property name="JDBC.ConnectionURL"
value="jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=UTF-8" />
<property name="JDBC.Username" value="root" />
<property name="JDBC.Password" value="" />
<!-- 连接池配置 -->
<property name="Pool.MaximumActiveConnections" value="10" />
<property name="Pool.MaximumIdleConnections" value="5" />
<property name="Pool.MaximumCheckoutTime" value="120000" />
<property name="Pool.TimeToWait" value="500" />
<property name="Pool.PingQuery" value="select 1 from sample" />
<property name="Pool.PingEnabled" value="false" />
<property name="Pool.PingConnectionsOlderThan" value="1" />
<property name="Pool.PingConnectionsNotUsedFor" value="1" />
</dataSource>
</transactionManager>
<!-- 映射文件 -->
<sqlMap resource="maps/User.xml" />
</sqlMapConfig>
5. 使用iBatis访问数据库:
package test;
import java.io.IOException;
import java.io.Reader;
import java.util.List;
import com.ibatis.common.resources.Resources;
import com.ibatis.sqlmap.client.SqlMapClient;
import com.ibatis.sqlmap.client.SqlMapClientBuilder;
import domain.User;
public class Test {
public static enum Mode {
INSERT, UPDATE, DELETE
}
public void update(Object arg, Mode mode) {
SqlMapClient smc = null;
try {
smc = getSqlMapClient();
smc.startTransaction();
switch (mode) {
case INSERT: smc.insert("insertUser", arg); break;
case UPDATE: smc.update("updateUser", arg); break;
case DELETE: smc.delete("deleteUser", arg); break;
}
smc.commitTransaction();
} catch (Exception e) {
e.printStackTrace();
} finally {
endTransaction(smc);
}
}
public void listUsers() {
SqlMapClient smc = null;
try {
smc = getSqlMapClient();
smc.startTransaction();
List users = smc.queryForList("getAllUsers", null);
System.out.println(users);
smc.commitTransaction();
} catch (Exception e) {
e.printStackTrace();
} finally {
endTransaction(smc);
}
}
public User selectUser(int id) {
User user = null;
SqlMapClient smc = null;
try {
smc = getSqlMapClient();
smc.startTransaction();
user = (User) smc.queryForObject("getUser", id);
smc.commitTransaction();
} catch (Exception e) {
e.printStackTrace();
} finally {
endTransaction(smc);
}
return user;
}
// ////////////////////////////////////////////////////////////////////////
// Don't care
// ////////////////////////////////////////////////////////////////////////
private SqlMapClient getSqlMapClient() throws IOException {
// 初始化ibatis, 获得一个SqlMapClient对象
String resource = "SqlMapConfig.xml";
Reader reader = Resources.getResourceAsReader(resource);
return SqlMapClientBuilder.buildSqlMapClient(reader);
}
private void endTransaction(SqlMapClient smc) {
if (smc == null) { return; }
try {
smc.endTransaction();
} catch (Exception e2) {
e2.printStackTrace();
}
}
public static void main(String[] args) {
Test t = new Test();
t.listUsers();
User user = new User("Biao");
user = t.selectUser(7);
user.setName("Biao 黄河");
t.update(user, Mode.UPDATE);
// t.update(user, Mode.INSERT);
// t.update(Integer.valueOf(7), Mode.DELETE);
t.listUsers();
}
}
