使用jotm实现跨数据库事务控制
测试环境：mysql-5.5.14，Oracle 10g Express，ow2-jotm-dist-2.1.9，JDK7，Win7
1，背景说明：两个数据库中分别有一张用户表，表结构设计类似，如下：MySQL中：?
CREATE TABLE TUSER( id INT, name VARCHAR(10) NOT NULL, PRIMARY KEY (id))?Oracle中:?create table TUSER( id int primary key, name VARCHAR2(10 CHAR) not null)?系统要求同时保存用户信息到这两个数据库中的用户表中。2,新建Java Project，将两个数据库的驱动以及jotm中lib目录下的相关jar文件加入buildpath中
3，编写实体类?package com.tanlan.jta.entity;public class User {private int id;private String 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;}}4，编写DAO?package com.tanlan.jta.dao;import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.SQLException;import com.tanlan.jta.entity.User;public class UserDAO {/** * 增加用户信息到MySQL数据库中 * * @param user * @param connection * @throws SQLException */public void addUserToMySQL(User user, Connection connection)throws SQLException {String sql = "insert into TUser values(?,?)";PreparedStatement pstmt = connection.prepareStatement(sql);pstmt.setInt(1, user.getId());pstmt.setString(2, user.getName());pstmt.execute();}/** * 增加用户信息到Oracle数据库中 * * @param user * @param connection * @throws SQLException */public void addUserToOracle(User user, Connection connection)throws SQLException {String sql = "insert into TUser values(?,?)";PreparedStatement pstmt = connection.prepareStatement(sql);pstmt.setInt(1, user.getId());pstmt.setString(2, user.getName());pstmt.execute();}}?5，编写帮助类，实现启动与停止事务管理服务，以及取得数据库连接：?package com.tanlan.jta.dao;import java.sql.Connection;import javax.naming.NamingException;import javax.sql.XAConnection;import javax.transaction.UserTransaction;import org.enhydra.jdbc.standard.StandardXADataSource;import org.objectweb.jotm.Jotm;import org.objectweb.transaction.jta.TMService;public class JotmHelper {private TMService jotm;private UserTransaction userTransaction;/** * 启动事务管理服务 */public void startTMService() {try {jotm = new Jotm(true, false);userTransaction = jotm.getUserTransaction();} catch (NamingException e1) {e1.printStackTrace();}}/** * 取得数据库连接 * * @param db * @return * @throws Exception */public Connection getConnection(String db) throws Exception {StandardXADataSource xads = new StandardXADataSource();XAConnection xaconn = null;if ("mysql".equals(db)) {xads.setDriverName("com.mysql.jdbc.Driver");xads.setUrl("jdbc:mysql://localhost/test");xads.setTransactionManager(jotm.getTransactionManager());xaconn = xads.getXAConnection("root", "root");} else if ("oracle".equals(db)) {xads.setDriverName("oracle.jdbc.driver.OracleDriver");xads.setUrl("jdbc:oracle:thin:@localhost:1521:XE");xads.setTransactionManager(jotm.getTransactionManager());xaconn = xads.getXAConnection("tanlan", "tanlan");} else {}return xaconn.getConnection();}public void begin() {try {userTransaction.begin();} catch (Exception e) {e.printStackTrace();}}public void commit() {try {userTransaction.commit();} catch (Exception e) {e.printStackTrace();}}public void rollback() {try {userTransaction.rollback();} catch (Exception e) {e.printStackTrace();}}/** * 停止事务管理服务 */public void stopTMService() {jotm.stop();jotm = null;}}?6，测试代码?package com.tanlan.jta.test;import java.sql.Connection;import com.tanlan.jta.dao.JotmHelper;import com.tanlan.jta.dao.UserDAO;import com.tanlan.jta.entity.User;public class TestUSer {public static void main(String[] args) {User user=new User();user.setId(300);user.setName("a122456");UserDAO dao = new UserDAO();JotmHelper helper = new JotmHelper();try {helper.startTMService();Connection mysqlConn = helper.getConnection("mysql");Connection oracleConn = helper.getConnection("oracle");helper.begin();dao.addUserToMySQL(user, mysqlConn);dao.addUserToOracle(user, oracleConn);helper.commit();} catch (Exception e) {helper.rollback();e.printStackTrace();} finally {helper.stopTMService();}}}?经过测试，这种方法能够较好的控制对两个数据库操作数据的事务。
