HTTP删除请求正文问题

Question

谁能解释以下内容:

package com.foo.bar;

import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.ProtocolException;
import java.net.URL;
import org.springframework.util.FileCopyUtils;

public class ATest {

    public static void main(String[] args) throws Exception {
       try {
           final String payload = "{\"parentExecutor\":\"foo1233\"}";
           URL url = new URL("http://localhost/notes");
           final HttpURLConnection connection = (HttpURLConnection) url.openConnection();
           connection.setRequestMethod("DELETE");
           connection.setRequestProperty("Accept", "application/json");
           connection.setRequestProperty("Content-Type", "application/json");
           FileCopyUtils.copy(payload.getBytes(), connection.getOutputStream());
           connection.connect();
           final InputStream is = connection.getInputStream();
           int b = is.read();
           String result = "";
           while (b != -1) {
               result += (char) b;
               b = is.read();
           }
           System.out.println(connection.getResponseCode());
           System.out.println(result);
           is.close();
       }
       catch (final ProtocolException e) {
          e.printStackTrace();
       }
   }
}

上面的示例抛出以下异常:

java.net.ProtocolException: cannot write to a URLConnection if doOutput=false - call setDoOutput(true)
    at sun.net.www.protocol.http.HttpURLConnection.getOutputStream(HttpURLConnection.java:995)
    at com.foo.bar.ATest.main(ATest.java:24)

但是,如果我添加对setDoOutput(true)的调用,则抛出以下异常:

java.net.ProtocolException: HTTP method DELETE doesn't support output
    at sun.net.www.protocol.http.HttpURLConnection.getOutputStream(HttpURLConnection.java:1004)
    at com.foo.bar.ATest.main(ATest.java:25)

然后,如果我将协议从http更改为https,则不会抛出任何异常,我从服务器返回预期的响应代码和内容.我查看了源代码,可以跟踪调用并跟踪异常发生的位置,但为什么通过HTTPS而不是HTTP发出这样的请求呢？

Answer 1

这是一个限制(我认为它是一个错误或至少是一个愚蠢的功能)HttpURLConnection.在使用REST Web服务时,您至少不是唯一遇到此问题的人URLConnection.

请考虑使用Apache HttpComponents Client.