java异常，具体描述如下，请问如何解决

Question

程序代码如下：
package mytest;

import java.net.URL;
import java.io.*;

public class URLDemo {

public static void main(String[] args) throws IOException {
    // TODO Auto-generated method stub
    URL addr = new URL("file://E:/Detect.txt"); //本地文本文件
    InputStream is = addr.openStream();
    BufferedReader br = new BufferedReader(
                new InputStreamReader(is)
            );
    while(true){  //从输入流不断读入数据，直到读完位置
        String s = br.readLine();
        if(null == s)break;
        System.out.println(s);
    }
}

}
运行错误：
Exception in thread "main" java.net.UnknownHostException: E
at java.net.AbstractPlainSocketImpl.connect(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at sun.net.ftp.impl.FtpClient.doConnect(Unknown Source)
at sun.net.ftp.impl.FtpClient.tryConnect(Unknown Source)
at sun.net.ftp.impl.FtpClient.connect(Unknown Source)
at sun.net.ftp.impl.FtpClient.connect(Unknown Source)
at sun.net.www.protocol.ftp.FtpURLConnection.connect(Unknown Source)
at sun.net.www.protocol.ftp.FtpURLConnection.getInputStream(Unknown Source)
at java.net.URL.openStream(Unknown Source)
at mytest.URLDemo.main(URLDemo.java:11)
请问如何解决？

Answer 1

执行了下你的代码，是file路径访问错误，去掉一个斜杠OK。修正如下:

 URL addr = new URL("file:/E:/Detect.txt"); //本地文本文件