在Java项目中如果发送http请求实现文件上传功能？相信很多没有经验的人对此束手无策，为此本文总结了问题出现的原因和解决方法，通过这篇文章希望你能解决这个问题。
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具体代码如下所示：
package wxapi.WxHelper;
import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.util.Date;
import java.util.Map;
import java.util.Map.Entry;
public class HttpRequestUtil {
/**
* 发送get请求
*
* @param requestUrl
* 请求url
* @param requestHeader
* 请求头
* @param responseEncoding
* 响应编码
* @return 页面响应html
*/
public static String sendGet(String requestUrl, Map requestHeader, String responseEncoding) {
String result = "";
BufferedReader reader = null;
try {
if (requestUrl == null || requestUrl.isEmpty()) {
return result;
}
URL realUrl = new URL(requestUrl);
URLConnection connection = realUrl.openConnection();
connection.setRequestProperty("accept", "text/html, application/xhtml+xml, image/jxr, */*");
connection.setRequestProperty("user-agent", "Mozilla/5.0 (Windows NT 10.0; WOW64; rv:53.0) Gecko/20100101 Firefox/53.0");
if (requestHeader != null && requestHeader.size() > 0) {
for (Entry entry : requestHeader.entrySet()) {
connection.setRequestProperty(entry.getKey(), entry.getValue());
}
}
connection.connect();
if (responseEncoding == null || responseEncoding.isEmpty()) {
responseEncoding = "UTF-8";
}
reader = new BufferedReader(new InputStreamReader(connection.getInputStream(), responseEncoding));
String line;
while ((line = reader.readLine()) != null) {
result += line;
}
} catch (Exception e) {
System.out.println("发送GET请求出现异常！");
e.printStackTrace();
} finally {
try {
if (reader != null) {
reader.close();
}
} catch (Exception e) {
e.printStackTrace();
}
}
return result;
}
/**
* 发送post请求
*
* @param requestUrl
* 请求url
* @param requestHeader
* 请求头
* @param formTexts
* 表单数据
* @param files
* 上传文件
* @param requestEncoding
* 请求编码
* @param responseEncoding
* 响应编码
* @return 页面响应html
*/
public static String sendPost(String requestUrl, Map requestHeader, Map formTexts, Map files, String requestEncoding, String responseEncoding) {
OutputStream out = null;
BufferedReader reader = null;
String result = "";
try {
if (requestUrl == null || requestUrl.isEmpty()) {
return result;
}
URL realUrl = new URL(requestUrl);
HttpURLConnection connection = (HttpURLConnection) realUrl.openConnection();
connection.setRequestProperty("accept", "text/html, application/xhtml+xml, image/jxr, */*");
connection.setRequestProperty("user-agent", "Mozilla/5.0 (Windows NT 10.0; WOW64; rv:53.0) Gecko/20100101 Firefox/53.0");
if (requestHeader != null && requestHeader.size() > 0) {
for (Entry entry : requestHeader.entrySet()) {
connection.setRequestProperty(entry.getKey(), entry.getValue());
}
}
connection.setDoOutput(true);
connection.setDoInput(true);
connection.setRequestMethod("POST");
if (requestEncoding == null || requestEncoding.isEmpty()) {
requestEncoding = "UTF-8";
}
if (responseEncoding == null || responseEncoding.isEmpty()) {
responseEncoding = "UTF-8";
}
if (requestHeader != null && requestHeader.size() > 0) {
for (Entry entry : requestHeader.entrySet()) {
connection.setRequestProperty(entry.getKey(), entry.getValue());
}
}
if (files == null || files.size() == 0) {
connection.setRequestProperty("content-type", "application/x-www-form-urlencoded");
out = new DataOutputStream(connection.getOutputStream());
if (formTexts != null && formTexts.size() > 0) {
String formData = "";
for (Entry entry : formTexts.entrySet()) {
formData += entry.getKey() + "=" + entry.getValue() + "&";
}
formData = formData.substring(0, formData.length() - 1);
out.write(formData.toString().getBytes(requestEncoding));
}
} else {
String boundary = "-----------------------------" + String.valueOf(new Date().getTime());
connection.setRequestProperty("content-type", "multipart/form-data; boundary=" + boundary);
out = new DataOutputStream(connection.getOutputStream());
if (formTexts != null && formTexts.size() > 0) {
StringBuilder sbFormData = new StringBuilder();
for (Entry entry : formTexts.entrySet()) {
sbFormData.append("--" + boundary + "\r\n");
sbFormData.append("Content-Disposition: form-data; name=\"" + entry.getKey() + "\"\r\n\r\n");
sbFormData.append(entry.getValue() + "\r\n");
}
out.write(sbFormData.toString().getBytes(requestEncoding));
}
for (Entry entry : files.entrySet()) {
String fileName = entry.getKey();
String filePath = entry.getValue();
if (fileName == null || fileName.isEmpty() || filePath == null || filePath.isEmpty()) {
continue;
}
File file = new File(filePath);
if (!file.exists()) {
continue;
}
out.write(("--" + boundary + "\r\n").getBytes(requestEncoding));
out.write(("Content-Disposition: form-data; name=\"" + fileName + "\"; filename=\"" + file.getName() + "\"\r\n").getBytes(requestEncoding));
out.write(("Content-Type: application/x-msdownload\r\n\r\n").getBytes(requestEncoding));
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();
out.write(("\r\n").getBytes(requestEncoding));
}
out.write(("--" + boundary + "--").getBytes(requestEncoding));
}
out.flush();
out.close();
out = null;
reader = new BufferedReader(new InputStreamReader(connection.getInputStream(), responseEncoding));
String line;
while ((line = reader.readLine()) != null) {
result += line;
}
} catch (Exception e) {
System.out.println("发送POST请求出现异常！");
e.printStackTrace();
} finally {
try {
if (out != null) {
out.close();
}
if (reader != null) {
reader.close();
}
} catch (IOException ex) {
ex.printStackTrace();
}
}
return result;
}
} 看完上述内容，你们掌握在Java项目中如果发送http请求实现文件上传功能的方法了吗？如果还想学到更多技能或想了解更多相关内容，欢迎关注创新互联行业资讯频道，感谢各位的阅读！
