Java|try-with-resource

如果有需要关闭的资源（比如文件、socket）想让try-catch关掉，可以用try-with-resource语法：

try(
    FileReader fr = new FileReader(src);
    BufferedReader br = new BufferedReader(fr);
    FileWriter wr = new FileWriter(target)
) {} 
catch(Exception e) {}