java远程连接服务器（或第三方接口）

迷南。 2021-10-13 02:57 299阅读 0赞

java 连接服务器，以multipart/form-data形式。上传文件或图片参数  
注意：在拼接格式的时候一定要注意空格 ，要不容易出错。  
![在这里插入图片描述][20190821121120102.png]

package com.aem.sheep.util;
    
    import java.io.BufferedReader;
    import java.io.DataInputStream;
    import java.io.DataOutputStream;
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.InputStreamReader;
    import java.io.OutputStream;
    import java.net.HttpURLConnection;
    import java.net.URL;
    
    import javax.activation.MimetypesFileTypeMap;
    
    import org.springframework.stereotype.Component;
    
    @Component
    public class Test {
    	/**
    	 * @param args
    	 */
    	public static void main(String[] args) {
    		// 服务器或第三方接口地址
    		String urlStr = "http://192.168.1.1:80/param/form";
    		String res = "";
    		HttpURLConnection conn = null;
    		// PrintWriter out = null;
    		// boundary就是request头和上传文件内容的分隔符
    		String BOUNDARY = "----WebKitFormBoundary7MA4YWxkTrZu0gW";
    		try {
    			StringBuffer strBuf = new StringBuffer();
    			String str = "";
    			URL url = new URL(urlStr);
    			conn = (HttpURLConnection) url.openConnection();
    
    			conn.setRequestProperty("Content-Type",
    					"multipart/form-data; boundary=" + BOUNDARY);
    			conn.setRequestProperty("Accept", "*/*");
    			conn.setRequestProperty("Cache-Control", "no-cache");
    			conn.setRequestProperty("User-Agent",
    					"Mozilla/5.0 (Windows; U; Windows NT 6.1; zh-CN; rv:1.9.2.6)");
    			conn.setRequestProperty("Connection", "Keep-Alive");
    			conn.setRequestProperty("cache-control", "no-cache");
    			conn.setRequestProperty("Charsert", "UTF-8");
    			conn.setDoOutput(true);
    			conn.setDoInput(true);
    			OutputStream out = new DataOutputStream(conn.getOutputStream());
    			// text
    
    			str += "\r\n" + "--" + BOUNDARY + "\r\n"
    					+ "Content-Disposition: form-data; name=\"" + "param_id"
    					+ "\"" + "\r\n\r\n";
    			str += "1011";
    			// CacheUtil.REALPATH 指服务器的路径
    			// 上传文件或图片地址
    			String filePath = CacheUtil.REALPATH + "img\\" + "123" + ".jpg";
    			File file = new File(filePath);
    			String filename = file.getName();
    
    			// 没有传入文件类型，同时根据文件获取不到类型，默认采用application/octet-stream
    			String contentType = new MimetypesFileTypeMap()
    					.getContentType(file);
    			// contentType非空采用filename匹配默认的图片类型
    			if (!"".equals(contentType)) {
    				if (filename.endsWith(".png")) {
    					contentType = "image/png";
    				} else if (filename.endsWith(".jpg")
    						|| filename.endsWith(".jpeg")
    						|| filename.endsWith(".jpe")) {
    					contentType = "image/jpeg";
    				} else if (filename.endsWith(".gif")) {
    					contentType = "image/gif";
    				} else if (filename.endsWith(".ico")) {
    					contentType = "image/image/x-icon";
    				}
    			}
    			if (contentType == null || "".equals(contentType)) {
    				contentType = "application/octet-stream";
    			}
    			// StringBuffer strBuf = new StringBuffer();
    			str += "\r\n" + "--" + BOUNDARY + "\r\n"
    					+ "Content-Disposition: form-data; name=\"" + "img"
    					+ "\"; filename=\"" + filename + "\"\r\n";
    			str += "Content-Type: " + contentType + "\r\n\r\n";
    			System.out.println("发送：" + str);
    			out.write(str.getBytes("utf-8"));
    			DataInputStream in = new DataInputStream(new FileInputStream(file));
    			int bytes = 0;
    			byte[] bufferOut = new byte[1024];
    			while ((bytes = in.read(bufferOut)) != -1) {
    				out.write(bufferOut, 0, bytes);
    			}
    			in.close();
    			str += "\r\n--" + BOUNDARY + "--\r\n";
    			out.write(str.getBytes("utf-8"));//以utf8编码形式发送
    			out.flush();
    			out.close();
    			// 读取返回数据
    			// StringBuffer strBuf = new StringBuffer();
    			BufferedReader reader = new BufferedReader(new InputStreamReader(
    					conn.getInputStream()));
    			String line = null;
    			while ((line = reader.readLine()) != null) {
    				strBuf.append(line).append("\n");
    			}
    			res = strBuf.toString();
    			System.out.println("返回信息：" + res);
    			reader.close();
    			reader = null;
    		} catch (Exception e) {
    			System.out.println("发送POST请求出错。" + urlStr);
    			e.printStackTrace();
    		} finally {
    			if (conn != null) {
    				conn.disconnect();
    				conn = null;
    			}
    
    		}
    	}
    }

[20190821121120102.png]: /images/20211013/f41920acfb3d461094fe1cb9f4b7b076.png