Java try-with-resources 语句在编译时被报告为错误

Question

核心 Java 第二卷高级功能 一书中的一个示例使用了 try-with-resources 语句作为一个简单的回显服务器程序。但是，当我编译程序时，编译器报告了下面程序代码后显示的错误。谢谢你的帮助。

程序代码：

 /**
 * Listing 3.3 server/EchoServer.java
 */
 package server;

 import java.io.*;
 import java.net.*;
 import java.util.*;

 /**
  * This pgoram implements a simple server
  * that listens to port 8189 and echoes
  *  back all client input.
  * @version 1.21 2012-05-19
  * @author Cay Horstmann
  */
 public class EchoServer {
    public static void main(String[] args) {
        // establish server socket
        try (ServerSocket s = new ServerSocket(8189)) {
            // wait for client connection
            try (Socket incoming = s.accept()) {
                InputStream inStream = incoming.getInputStream();
                OutputStream outStream = incoming.getOutputStream();
                try (Scanner in = new Scanner(inStream)) {
                    PrintWriter out = new PrintWriter(outStream, true /*autoFlush*/);
                    out.println("Heloo! Enter BYE to exit");
                    // echo client input
                    boolean done = false;
                    while (!done && in.hasNext()) {
                        String line = in.nextLine();
                        out.println("Echo: " + line);
                        if (line.trim().toUpperCase().equals("BYE"))
                            done = true;
                    }
                }
            }
        }
    }
 }

编译器报告的错误信息：

Answer 1

正如错误所说

try-with-resources 会自动关闭您在块末尾的 try(...) 中声明的资源，但它不会为您自动处理异常。

所以你要么需要：

写入 catch 块以处理 IOExceptions
声明方法 (main) 抛出这些异常。

Java try-with-resources 语句在编译时被报告为错误

Java try-with-resources statements were reproted as error at compile time

java

try-with-resources