JDBC事务处理

     connection.rollback();//回滚事务。

    例子：

   public class TxTest {


/**
* @param args
* @throws SQLException
*/
public static void main(String[] args) throws SQLException {
test();
}


static void test() throws SQLException {
Connection conn = null;
Statement st = null;
ResultSet rs = null;
try {
conn = JdbcUtils.getConnection();
conn.setAutoCommit(false);//1、打开事务
conn.setTransactionIsolation(Connection.TRANSACTION_READ_COMMITTED);
st = conn.createStatement();
String sql = "update user set money=money-10 where id=1";
st.executeUpdate(sql);
sql = "select money from user where id=2";
rs = st.executeQuery(sql);
float money = 0.0f;
if (rs.next()) {
money = rs.getFloat("money");
}
if (money > 400)
throw new RuntimeException("已经超过最大值！");
sql = "update user set money=money+10 where id=2";
st.executeUpdate(sql);
conn.commit();//2、提交事务
} catch (SQLException e) {
if (conn != null)
conn.rollback();//3、回滚事务
throw e;
} finally {
JdbcUtils.free(rs, st, conn);
}
}
}

当money大于400时候超过最大值，抛出异常，conn.rollback();  2条sql都会回滚不会执行。

适用于多条sql必须都执行才有效;