java try with resource

你可以在块中使用多个资源而且这些资源都能被自动地关闭。下面是例子：

private static void printFileJava7() throws IOException {
   try(  FileInputStream     input         = new FileInputStream("file.txt");
         BufferedInputStream bufferedInput = new BufferedInputStream(input)
   ) {
       int data = bufferedInput.read();
       while(data != -1){
           System.out.print((char) data);
           data = bufferedInput.read();
       }
   }
}

在java 9中可更为简洁,可以将变量单独放在外边：

private static void printFileJava7() throws IOException {
    FileInputStream     input         = new FileInputStream("file.txt");
    BufferedInputStream bufferedInput = new BufferedInputStream(input)
    try(  input;bufferedInput) {
        int data = bufferedInput.read();
        while(data != -1){
            System.out.print((char) data);
            data = bufferedInput.read();
        }
    }
}

参考资料：
http://ifeve.com/java-7%E4%B8%AD%E7%9A%84try-with-resources/
在 JDK 9 中更简洁使用 try-with-resources 语句