HttpURLConnection POST 上传文件

package com.popo.http;import java.io.ByteArrayOutputStream;import java.io.DataOutputStream;import java.io.File;import java.io.FileInputStream;import java.io.InputStream;import java.net.HttpURLConnection;import java.net.SocketTimeoutException;import java.net.URL;import java.net.URLEncoder;import java.util.HashMap;import java.util.Iterator;import java.util.Map;import java.util.Set;import javax.imageio.ImageIO;import javax.imageio.ImageReader;import javax.imageio.stream.ImageInputStream;public class HttpPostUtil {URL url;HttpURLConnection conn;String boundary = "--------httppost123";Map<String, String> textParams = new HashMap<String, String>();Map<String, File> fileparams = new HashMap<String, File>();DataOutputStream ds;public HttpPostUtil(String url) throws Exception {this.url = new URL(url);}    //重新设置要请求的服务器地址，即上传文件的地址。public void setUrl(String url) throws Exception {this.url = new URL(url);}    //增加一个普通字符串数据到form表单数据中public void addTextParameter(String name, String value) {textParams.put(name, value);}    //增加一个文件到form表单数据中public void addFileParameter(String name, File value) {fileparams.put(name, value);}    // 清空所有已添加的form表单数据public void clearAllParameters() {textParams.clear();fileparams.clear();}    // 发送数据到服务器，返回一个字节包含服务器的返回结果的数组public byte[] send() throws Exception {initConnection();try {conn.connect();} catch (SocketTimeoutException e) {// somethingthrow new RuntimeException();}ds = new DataOutputStream(conn.getOutputStream());writeFileParams();writeStringParams();paramsEnd();InputStream in = conn.getInputStream();ByteArrayOutputStream out = new ByteArrayOutputStream();int b;while ((b = in.read()) != -1) {out.write(b);}out.flush();conn.disconnect();return out.toByteArray();}    //文件上传的connection的一些必须设置private void initConnection() throws Exception {conn = (HttpURLConnection) this.url.openConnection();conn.setDoOutput(true);conn.setUseCaches(false);conn.setConnectTimeout(10000); //连接超时为10秒conn.setRequestMethod("POST");conn.setRequestProperty("Content-Type","multipart/form-data; boundary=" + boundary);conn.setChunkedStreamingMode(1024 * 50);}    //普通字符串数据private void writeStringParams() throws Exception {Set<String> keySet = textParams.keySet();for (Iterator<String> it = keySet.iterator(); it.hasNext();) {String name = it.next();String value = textParams.get(name);ds.writeBytes("--" + boundary + "\r\n");ds.writeBytes("Content-Disposition: form-data; name=\"" + name+ "\"\r\n");ds.writeBytes("\r\n");ds.writeBytes(encode(value) + "\r\n");}}    //文件数据private void writeFileParams() throws Exception {Set<String> keySet = fileparams.keySet();for (Iterator<String> it = keySet.iterator(); it.hasNext();) {String name = it.next();File value = fileparams.get(name);ds.writeBytes("--" + boundary + "\r\n");ds.writeBytes("Content-Disposition: form-data; name=\"" + name+ "\"; filename=\"" + encode(value.getName()) + "\"\r\n");ds.writeBytes("Content-Type: " + getContentType(value) + "\r\n");ds.writeBytes("\r\n");ds.write(getBytes(value));ds.writeBytes("\r\n");}}    //获取文件的上传类型，图片格式为image/png,image/jpg等。非图片为application/octet-streamprivate String getContentType(File f) throws Exception {//return "application/octet-stream";  // 此行不再细分是否为图片，全部作为application/octet-stream 类型ImageInputStream imagein = ImageIO.createImageInputStream(f);if (imagein == null) {return "application/octet-stream";}Iterator<ImageReader> it = ImageIO.getImageReaders(imagein);if (!it.hasNext()) {imagein.close();return "application/octet-stream";}imagein.close();return "image/" + it.next().getFormatName().toLowerCase();//将FormatName返回的值转换成小写，默认为大写}    //把文件转换成字节数组private byte[] getBytes(File f) throws Exception {FileInputStream in = new FileInputStream(f);ByteArrayOutputStream out = new ByteArrayOutputStream();byte[] b = new byte[1024];int n;while ((n = in.read(b)) != -1) {out.write(b, 0, n);}in.close();return out.toByteArray();}//添加结尾数据private void paramsEnd() throws Exception {ds.writeBytes("--" + boundary + "--" + "\r\n");ds.writeBytes("\r\n");}// 对包含中文的字符串进行转码，此为UTF-8。服务器那边要进行一次解码    private String encode(String value) throws Exception{    return URLEncoder.encode(value, "UTF-8");    }public static void main(String[] args) throws Exception {HttpPostUtil u = new HttpPostUtil("http://localhost");u.addFileParameter("img", new File("165247.txt"));u.addTextParameter("text", "中文");byte[] b = u.send();String result = new String(b);System.out.println(result);}}

原文来自：http://314858770.iteye.com/blog/720456