使用tomcat和jotm实现的一个JTA的例子

一、目的：在一个程序中，想达到对oracle数据库与sql server2000数据库的操作通过一个事务来管理，一起提交一起回滚，需要用到JTA。

参考文档：http://www.blogjava.net/zhanglijun33/archive/2006/09/21/jta.html

二、下面说下我的具体实现：

1、JOTM包：

下载地址：http://jotm.ow2.org/xwiki/bin/view/Main/Download_Releases

我用的是ow2-jotm-dist-2.1.9-bin，由于我使用的是比较新的JOTM版本，所以不需要考虑参考文档中4.1提到的问题。

2、tomcat环境：

(1)版本：5.5.26

(2)commons\lib:把ow2-jotm-dist-2.1.9\lib中的包都放进来。

(3)context.xml:

......

......

</Context>

4、web应用中的代码:

index.jsp:

<%@page contentType="text/html;charset=GB2312"%>
<%@page import="java.sql.*"%>
<%@page import="javax.sql.*"%>
<%@page import="javax.naming.*"%>
<%@page import="javax.transaction.UserTransaction"%>
<%
Connection connOracle = null;
Statement stmtOracle = null;
ResultSet rsOracle = null;
Connection connSql = null;
Statement stmtSql = null;
ResultSet rsSql = null;
UserTransaction ut = null;
try {
 Context initCtx = new InitialContext();
 Context envCtx = (Context) initCtx.lookup("java:comp/env");
 DataSource dsOracle = (DataSource) envCtx.lookup("jdbc/orcldb");
 DataSource dsSql = (DataSource) envCtx.lookup("jdbc/sqldb");
 ut = (UserTransaction)initCtx.lookup("java:comp/UserTransaction");
 connOracle = dsOracle.getConnection();
 connSql = dsSql.getConnection();

 ut.begin();
 System.out.println("<<< beginning the transaction >>>");

 stmtOracle = connOracle.createStatement(
 // ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_UPDATABLE
 );
 rsOracle = stmtOracle.executeQuery("SELECT PRICE FROM TM_PRODUCT WHERE ID=1");
 rsOracle.next();
 stmtSql = connSql.createStatement(
 // ResultSet.TYPE_SCROLL_INSENSITIVE, ResultSet.CONCUR_UPDATABLE
 );
 rsSql = stmtSql.executeQuery("SELECT PRICE FROM TM_PRODUCT WHERE ID=1");
 rsSql.next();
} catch(Exception e) {
 e.printStackTrace();
}
%>
<html>
<body>
Original price Oracle:
<%=rsOracle.getString("price")%>
 Original price Sql:
<%=rsSql.getString("price")%>
 After update Oracle:
<%
PreparedStatement pstmtOracle = connOracle.prepareStatement("update tm_product set price=? where id=1");
pstmtOracle.setInt(1,101);
pstmtOracle.executeUpdate();
rsOracle = stmtOracle.executeQuery("SELECT PRICE FROM TM_PRODUCT WHERE ID=1");
rsOracle.next();
%>
<%=rsOracle.getString("price")%>
 After update Sql:
<%
PreparedStatement pstmtSql = connSql.prepareStatement("update tm_product set price=? where id=1");
pstmtSql.setInt(1,101);
pstmtSql.executeUpdate();
rsSql = stmtSql.executeQuery("SELECT PRICE FROM TM_PRODUCT WHERE ID=1");
rsSql.next();
%>
<%=rsSql.getString("price")%>
<%
System.out.println("<<< rolling back the transaction >>>");
ut.rollback();//Or ut.commit();
%>
 After Rollback Oracle:
<%
rsOracle = stmtOracle.executeQuery("SELECT PRICE FROM TM_PRODUCT WHERE ID=1");
rsOracle.next();
%>
<%=rsOracle.getString("price")%>
<%connOracle.close();%>
 After Rollback Sql:
<%
rsSql = stmtSql.executeQuery("SELECT PRICE FROM TM_PRODUCT WHERE ID=1");
rsSql.next();
%>
<%=rsSql.getString("price")%>
<%connSql.close();%>
</body>
</html>

5、测试用数据的准备

oracle中：

create table tm_product(id number(9) primary key,price number(9));

insert into tm_product values(1,1200);

commit;

sql server2000中:

create table tm_product(id numeric(9) primary key,price numeric(9));

insert into tm_product values(1,1500);

6、异常处理

(1)java.lang.ClassCastException: org.objectweb.jotm.Current

我的应用Lib中的jta.jar冲突，去掉后OK

(2)java.sql.SQLException: [Microsoft][SQLServer 2000 Driver for JDBC]Can't start a cloned connection while in manual transaction mode.

参考：http://blog.sina.com.cn/s/blog_4ffb1bf201009ld3.html

7、页面结果展示

Original price Oracle: 1200
Original price Sql: 1500
After update Oracle: 101
After update Sql: 101
After Rollback Oracle: 1200
After Rollback Sql: 1500

ps:

ut的timeout设置：

ut.setTransactionTimeout(3600*5);