try(){}使用

InputStream is = null;

OutputStream os = null;

try {

} catch (IOException e) {

}finally{

try {

if(os!=null){

os.close();

}

if(is!=null){

is.close();

}

} catch (IOException e2) {

}

}

而现在你可以这样写:

 

 

try(

InputStream is = new FileInputStream("...");

OutputStream os = new FileOutputStream("...");

){

}catch (IOException e) {

}

 

 

 

 

try()里每个声明的变量类型都必须是Closeable的子类