我尝试通过 HTTP POST 发送文本和图像，但总是收到 400 错误。我想用它通过 Telegram 机器人发送图像，并且我正在使用此答案中提供的代码以及文本和咬合参数https://stackoverflow.com/a/2793153/1970613，并进行一些小的修改。
可能是什么错误？
String param = "chat_id=mi_id&photo=";
String charset = "UTF-8";
String request = "https://api.telegram.org/bot-botCOde/sendPhoto";
URL url = new URL( request );
File binaryFile = new File("/home/joseantonio/imagen.jpg");
String CRLF = "\r\n"; // Line separator required by multipart/form-data.
String boundary = Long.toHexString(System.currentTimeMillis());
HttpURLConnection conn= (HttpURLConnection) url.openConnection();
conn.setDoOutput( true );
conn.setInstanceFollowRedirects( false );
conn.setRequestMethod( "POST" );
conn.setRequestProperty( "charset", "utf-8");
conn.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + boundary);
conn.setUseCaches( false );
try {
OutputStream output = conn.getOutputStream();
PrintWriter writer = new PrintWriter(new OutputStreamWriter(output, charset), true);
writer.append("--" + boundary).append(CRLF);
writer.append("Content-Disposition: form-data; name=\"param\"").append(CRLF);
writer.append("Content-Type: text/plain; charset=" + charset).append(CRLF);
writer.append(CRLF).append(param).append(CRLF).flush();
writer.append("--" + boundary).append(CRLF);
writer.append("Content-Disposition: form-data; name=\"binaryFile\"; filename=\"" + binaryFile.getName() + "\"").append(CRLF);
writer.append("Content-Type: image/jpg").append(CRLF);
writer.append("Content-Transfer-Encoding: binary").append(CRLF);
writer.append(CRLF).flush();
Files.copy(binaryFile.toPath(), output);
output.flush(); // Important before continuing with writer!
writer.append(CRLF).flush(); // CRLF is important! It indicates end of boundary.
// End of multipart/form-data.
writer.append("--" + boundary + "--").append(CRLF).flush();
int responseCode2 = conn.getResponseCode();
System.out.println("\nSending 'GET' request to URL : " + request);
System.out.println("Response Code : " + responseCode2);```
我相信您使用 https url 的事实是您收到错误的原因。当您提交到 https url 时，您需要处理一些不同的事情。请参阅示例此处
我尝试修改你的代码并且它起作用了，这里是简单的SendTelegram.java
/*
* Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
* Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template
*/
package com.goblooge.test;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.nio.charset.Charset;
import java.nio.file.Files;
/**
*
* @author goblooge
*/
public class SendTelegram {
public static void main(String args[]) throws Exception{
String param = "chat_id=@yourchannel&photo=";
String charset = "UTF-8";
String request = "https://api.telegram.org/CHNAGE_WITH_YOUR_BOT_ID/sendPhoto?chat_id=@yourchannel";
URL url = new URL( request );
File binaryFile = new File("huda.jpg");
File ff = binaryFile;
String content_type = Files.probeContentType(binaryFile.toPath());
System.out.println(binaryFile.getAbsolutePath());
String CRLF = "\r\n"; // Line separator required by multipart/form-data.
String boundary = Long.toHexString(System.currentTimeMillis());
String CrLf = "\r\n";
HttpURLConnection conn= (HttpURLConnection) url.openConnection();
conn.setDoOutput( true );
conn.setInstanceFollowRedirects( false );
conn.setRequestMethod( "POST" );
conn.setRequestProperty( "charset", "utf-8");
conn.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + boundary);
conn.setUseCaches( false );
String postData = "";
InputStream imgIs = new FileInputStream(ff);
byte[] imgData = new byte[imgIs.available()];
imgIs.read(imgData);
String message1 = "";
message1 += "-----------------------------"+boundary + CrLf;
message1 += "Content-Disposition: form-data; name=\"photo\"; filename=\""+ff.getName()+"\""
+ CrLf;
message1 += "Content-Type: "+content_type+ CrLf;
message1 += CrLf;
// the image is sent between the messages in the multipart message.
String message2 = "";
message2 += CrLf + "-----------------------------"+boundary+"--"
+ CrLf;
conn.setRequestProperty("Content-Type",
"multipart/form-data; boundary=---------------------------"+boundary);
// might not need to specify the content-length when sending chunked
// data.
conn.setRequestProperty("Content-Length", String.valueOf((message1
.length() + message2.length() + imgData.length)));
OutputStream os = conn.getOutputStream();
System.out.println(message1);
os.write(message1.getBytes());
// SEND THE IMAGE
int index = 0;
int size = 1024;
do {
System.out.println("write:" + index);
if ((index + size) > imgData.length) {
size = imgData.length - index;
}
os.write(imgData, index, size);
index += size;
} while (index < imgData.length);
System.out.println("written:" + index);
System.out.println(message2);
os.write(message2.getBytes());
os.flush();
System.out.println("open is");
InputStream is = conn.getInputStream();
char buff = 512;
int len;
byte[] data = new byte[buff];
do {
System.out.println("READ");
len = is.read(data);
if (len > 0) {
System.out.println(new String(data, 0, len));
}
} while (len > 0);
System.out.println("DONE");
/*
PrintWriter writer = new PrintWriter(new OutputStreamWriter(output, charset), true);
writer.append("--" + boundary).append(CRLF);
writer.append("Content-Disposition: form-data; name=\"photo\" filename=\""+binaryFile.getName()+"\"").append(CRLF);
writer.append("Content-Type: "+content_type+"; charset=" + charset).append(CRLF);
writer.append(CRLF).append(param).append(CRLF).flush();
writer.append("--" + boundary).append(CRLF);
writer.append("Content-Disposition: form-data; name=\"binaryFile\"; filename=\"" + binaryFile.getName() + "\"").append(CRLF);
writer.append("Content-Type: image/jpg").append(CRLF);
writer.append("Content-Transfer-Encoding: binary").append(CRLF);
writer.append(CRLF).flush();
Files.copy(binaryFile.toPath(), output);
output.flush(); // Important before continuing with writer!
writer.append(CRLF).flush(); // CRLF is important! It indicates end of boundary.
// End of multipart/form-data.
writer.append("--" + boundary + "--").append(CRLF).flush();
*/
int responseCode2 = conn.getResponseCode();
System.out.println("\nSending 'GET' request to URL : " + request);
System.out.println("Response Code : " + responseCode2);
}
}