MySQL分布式事务xa的介绍与使用小结

#1.开启一个xa事务，后面跟的字符串是xid，它是一个唯一的xa事务标识符
xa start '123';
#2.开启完xa事务后，就能执行业务sql了
update test_table set user = 'zhuzi' where id = 1;
#3.end代表业务sql执行完毕，后续可以开始二阶段提交工作了
xa end '123';
#4.第一阶段，进行准备工作
xa prepare '123';
#5.返回该MySQL上那些处于prepare阶段的xa事务的信息
xa recover;
#6.第二阶段，回滚或提交
xa commit '123';
#xa rollback '123';

GRANT xa_recover_admin ON *.* TO root@'%';

<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>8.0.28</version>
</dependency>

private static void testXA() {
    Connection connection1 = null;
    Connection connection2 = null;
    MysqlXAConnection xa1 = null;
    MysqlXAConnection xa2 = null;
    Statement statement1 = null;
    Statement statement2 = null;
    try {
        //获取两台MySQL的连接
        connection1 = DriverManager.getConnection("jdbc:mysql://192.168.86.111:3306/db3", "root", "123456");
        connection2 = DriverManager.getConnection("jdbc:mysql://192.168.86.112:3306/db1", "root", "123456");
        //获取XA连接 true表示打印日志
        xa1 = new MysqlXAConnection((JdbcConnection) connection1, true);
        xa2 = new MysqlXAConnection((JdbcConnection) connection2, true);
        //获取事务管理器
        XAResource resourceManager1 = xa1.getXAResource();
        XAResource resourceManager2 = xa2.getXAResource();

        //构造组成xid的三部分
        byte[] globalTransactionId = UUID.randomUUID().toString().replace("-", "").getBytes();
        byte[] branch1 = "分支1".getBytes();
        byte[] branch2 = "分支2".getBytes();
        int formatId = 1;
		//获取xid对象
        MysqlXid xid1 = new MysqlXid(globalTransactionId, branch1, formatId);
        MysqlXid xid2 = new MysqlXid(globalTransactionId, branch2, formatId);
        //要执行的业务sql
        String sql1 = "insert into test(`name`, `age`) values('竹子', 23)";
        String sql2 = "insert into employee(`employee_name`, `department_id`) values('竹叶', 1)";
        //执行xa start xid命令
        resourceManager1.start(xid1, XAResource.TMNOFLAGS);
        resourceManager2.start(xid2, XAResource.TMNOFLAGS);
        //执行业务sql
        statement1 = connection1.createStatement();
        statement1.execute(sql1);
        statement2 = connection2.createStatement();
        statement2.execute(sql2);
        //执行xa end xid命令
        resourceManager1.end(xid1, XAResource.TMSUCCESS);
        resourceManager2.end(xid2, XAResource.TMSUCCESS);

        //执行xa prepare xid命令
        int prepare1 = resourceManager1.prepare(xid1);
        int prepare2 = resourceManager2.prepare(xid2);
        //是否只存在一台MySQL，如果只存在一台MySQL，那么就不需要进行分布式的二阶段提交了
        boolean onePhase = false;
        //都准备好了
        if (prepare1 == XAResource.XA_OK && prepare2 == XAResource.XA_OK) {
            //执行xa commit xid命令
            resourceManager1.commit(xid1, onePhase);
            resourceManager2.commit(xid2, onePhase);
        } else {
            //执行xa rollback xid命令
            resourceManager1.rollback(xid1);
            resourceManager2.rollback(xid2);
        }
    } catch (SQLException | XAException e) {
        e.printStackTrace();
    } finally {
        try {
            statement1.close();
            statement2.close();
            xa1.close();
            xa2.close();
            connection1.close();
            connection2.close();
        } catch (SQLException throwables) {
            throwables.printStackTrace();
        }
    }
}