java Trywithresources：我必须抛出或捕获close（）方法的异常吗？

Question

如果这是错误的，请纠正我：在Java 7的try with resources语句中，由资源的close()方法引发的任何异常必须声明为由我的方法引发，或者我必须将整个尝试包装在另一个try中，该语句捕获由close()引发的任何异常

如果是这样，我想知道我是否会充分利用它。我当然不想看到throw由close()引发的异常，调用方不知道该怎么处理。而一个try包装另一个try只是为了处理close()至少在我看来不会很优雅

编辑：我想我不小心问了两个问题，其中一个是重复的

问题1。我必须声明我的方法从close()方法抛出异常，还是在另一次尝试中用资源包装该尝试？（建议的副本中未回答。）

问题2。有没有办法安静地关闭资源？（显然是重复的，所以我把这句话从问题中去掉。希望这能让问题令人满意地独一无二。）

Answer 1

引用Java Language Specification ($14.20.3.2)

14.20.3.2 Extended try-with-resources

A try-with-resources statement with at least one catch clause and/or a finally clause is called an extended try-with-resources statement. The meaning of an extended try-with-resources statement:

    try ResourceSpecification
        Block
    Catches_opt
    Finally_opt

is given by the following translation to a basic try-with-resources statement (§14.20.3.1) nested inside a try-catch or try-finally or try-catch-finally statement:

    try {
        try ResourceSpecification
            Block
    }
    Catches_opt
    Finally_opt

The effect of the translation is to put the ResourceSpecification "inside" the try statement. This allows a catch clause of an extended try-with-resources statement to catch an exception due to the automatic initialization or closing of any resource.

所以，基本上，包装器已经实现了

Answer 2

您应该能够简单地添加适当的catch (Exception e) { }子句。如果你需要对一个特定的对象进行特殊处理，或者你可以简单地捕捉Exception，如果你需要的话

try (Statement stmt = con.createStatement()) {
    ResultSet rs = stmt.executeQuery(query);

    while (rs.next()) {
        String coffeeName = rs.getString("COF_NAME");
        int supplierID = rs.getInt("SUP_ID");
        float price = rs.getFloat("PRICE");

        System.out.println(coffeeName + ", " + supplierID + ", " + 
                           price + ", " + sales + ", " + total);
    }
} catch (Exception e) {
    System.out.println("Exception while trying to through the queries. ", e);
}

因为它是Java 7，所以实际上可以在每个catch子句中放置多个异常，或者只需捕获所需的最外层异常