java - 从 catch 中以及从 finally block 中抛出异常

Question

我想抛出在对应用程序执行 MySQL 事务时发生的任何异常。但在此之前我想关闭所有处于打开状态的资源。但是关闭这些资源可能会再次生成异常，我想再次向应用程序报告该异常。下面的代码将使这一点变得更清楚:

try
{
   // connect to MySQL DB using JDBC and run different queries
}
catch ( Exception e )
{
   // throw this exception by wrapping it in another user defined exception class
}
finally
{
   try
   {
      // close resources opened in try block ( statement, connection )
   }
   catch ( Exception e )
   {
      // throw this exception by wrapping it in another user defined exception class
   }   
}

我想知道处理这种情况的正确方法是什么(抛出两个异常)。感谢您的帮助。

Answer 1

我建议您使用Java 7 The try-with-resources Statement

Oracle 文档对此进行了更好的解释

• Better Resource Management with Java SE 7: Beyond Syntactic Sugar

<小时/>

示例代码:

try(  Connection conn = dataSource.getConnection();
      PreparedStatement stmt = conn.prepareStatement(query);
      ResultSet rs = stmt.executeQuery() ) {
     // connection, statements and result set are automatically closed 
}

注意: try-with-resources 语句可以像普通语句一样具有 catch 和 finally block try 语句。在 try-with-resources 语句中，任何 catch 或 finally block 都会在声明的资源关闭.