如果发生异常，请尝试使用资源关闭资源？

Question

如果发生异常，请尝试使用资源关闭所有打开的资源？

private void insertUserInAccessTable(int user_id) throws SQLException { 
    final String sql = "bla bla"; 
    try(Connection con = ...; PreparedStatement ps = ...) { 
     ... 
     if(i==0) throw new SQLException(); 
    } 
} 

Answer 1

是的，但不是那些它的身体（在资源申报之后）。

// This connection is initialized beforehand and will not be 
// closed automatically by try-with-resources 
Connection conn = // ... 

// The statement WILL always be closed, exception or not, before exiting the try block 
try (Statement stmt = conn.createStatement()) 
{ 
    // This result set will NOT be closed (directly) by try-with-resources 
    ResultSet rs = stmt.executeQuery(/*...*/); 
} 

^*当试穿与资源关闭Statement，JDBC说，声明应该关闭它创建的ResultSet。所以它可能会被封闭，但只是因为JDBC合同而不是因为试用资源。

Answer 2

即使它会抛出异常，它也会被关闭。

将不管封闭的try语句是否完成 正常或突然

参考：这是try块或内外部的初始化 http://docs.oracle.com/javase/tutorial/essential/exceptions/tryResourceClose.html