首先看代码:

import org.junit.Test;

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStreamReader;

public class TryWithResources {

@Test
public void test() throws FileNotFoundException {


FileInputStream inputStream1 = new FileInputStream("e:\\ipscan.txt");
InputStreamReader reader1 = new InputStreamReader(inputStream1);
BufferedReader br1 = new BufferedReader(reader1);


FileInputStream inputStream2 = new FileInputStream("g:\\sample.txt");
InputStreamReader reader2 = new InputStreamReader(inputStream2);



BufferedReader br2 = new BufferedReader(reader2);

try(BufferedReader b3 = new BufferedReader(reader2);BufferedReader b4 = new BufferedReader(reader1))
{
System.out.println(br1.readLine()+br2.readLine());
}catch (Exception e)
{
System.err.println(e);
}

//JAVA9才支持
// try(br1;br2)
// {
// System.out.println(br1.readLine()+br2.readLine());
// }catch (Exception e)
// {
// System.err.println(e);
// }
}
}

使用前置条件:实现java.lang.AutoCloseable接口

java1.7引入的新特性。类似于C#的using语句块,只要类实现了IDisposable接口