在现在的网络开发中，上传图片类的需求实在是太普通不过了，但是对于怎么样做到上传图片，对于刚开始建立项目的时候，还是有点不知所措的。也许有幸，我们做的项目是之前已经有人写过类似的用例了，那么我们只需要依葫芦画瓢就行了。
好好了解下图片上传（文件上传）的方式，对于认知的提升还是有好处的。而且说不定哪天你就有个这样的需求呢，这里是一条龙上传。
本文就一个从app到php层，再到java层的流程，演译下整个上传图片的流程吧。
一、app端获取用户选择的图片，转化为输入流，上传至php前端接口：
package com.dia.ration;import java.io.DataOutputStream;import java.io.File;import java.io.FileInputStream;import java.io.IOException;import java.io.InputStream;import java.net.HttpURLConnection;import java.net.MalformedURLException;import java.net.URL;import java.util.HashMap;import java.util.Map;import java.util.UUID;/**
* 上传文件到服务器类 */public class UploadUtil { private static final String TAG = "uploadFile"; private static final int TIME_OUT = 10 * 1000; // 超时时间
private static final String CHARSET = "utf-8"; // 设置编码
/**
* Android上传文件到服务端
*
* @param file 需要上传的文件
* @param RequestURL 请求的rul
* @return 返回响应的内容 */
public static String uploadFile(File file, String RequestURL) {
String result = null;
String BOUNDARY = UUID.randomUUID().toString(); // 边界标识 随机生成
String PREFIX = "--", LINE_END = "\r\n";
String CONTENT_TYPE = "multipart/form-data"; // 内容类型
try {
URL url = new URL(RequestURL);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setReadTimeout(TIME_OUT);
conn.setConnectTimeout(TIME_OUT);
conn.setDoInput(true); // 允许输入流
conn.setDoOutput(true); // 允许输出流
conn.setUseCaches(false); // 不允许使用缓存
conn.setRequestMethod("POST"); // 请求方式
conn.setRequestProperty("Charset", CHARSET); // 设置编码
conn.setRequestProperty("connection", "keep-alive");
conn.setRequestProperty("Content-Type", CONTENT_TYPE + ";boundary=" + BOUNDARY); if (file != null) {
DataOutputStream dos = new DataOutputStream(conn.getOutputStream());
StringBuffer sb = new StringBuffer();
sb.append(PREFIX);
sb.append(BOUNDARY);
sb.append(LINE_END); /**
* 这里重点注意： name里面的值为服务端需要key 只有这个key 才可以得到对应的文件
* filename是文件的名字，包含后缀名的 比如:abc.png */
sb.append("Content-Disposition: form-data; name=\"uploadfile\"; filename=\""
+ file.getName() + "\"" + LINE_END);
sb.append("Content-Type: application/octet-stream; charset=" + CHARSET + LINE_END);
sb.append(LINE_END);
dos.write(sb.toString().getBytes());
InputStream is = new FileInputStream(file); byte[] bytes = new byte[1024]; int len = 0; while ((len = is.read(bytes)) != -1) {
dos.write(bytes, 0, len);
}
is.close();
dos.write(LINE_END.getBytes()); byte[] end_data = (PREFIX + BOUNDARY + PREFIX + LINE_END).getBytes();
dos.write(end_data);
dos.flush();
InputStream input = conn.getInputStream();
StringBuffer sb1 = new StringBuffer(); int ss; while ((ss = input.read()) != -1) {
sb1.append((char) ss);
}
result = sb1.toString();
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} return result;
} /**
* 通过拼接的方式构造请求内容，实现参数传输以及文件传输
*
* @param url Service net address
* @param params text content
* @param files pictures
* @return String result of Service response
* @throws IOException */
public static String post(String url, Map<String, String> params, Map<String, File> files) throws IOException {
String BOUNDARY = UUID.randomUUID().toString();
String PREFIX = "--", LINEND = "\r\n";
String MULTIPART_FROM_DATA = "multipart/form-data";
String CHARSET = "UTF-8";
URL uri = new URL(url);
HttpURLConnection conn = (HttpURLConnection) uri.openConnection();
conn.setReadTimeout(10 * 1000); // 缓存的最长时间
conn.setDoInput(true); // 允许输入
conn.setDoOutput(true); // 允许输出
conn.setUseCaches(false); // 不允许使用缓存
conn.setRequestMethod("POST");
conn.setRequestProperty("connection", "keep-alive");
conn.setRequestProperty("Charsert", "UTF-8");
conn.setRequestProperty("Content-Type", MULTIPART_FROM_DATA + ";boundary=" + BOUNDARY); // 首先组拼文本类型的参数
StringBuilder sb = new StringBuilder(); for (Map.Entry<String, String> entry : params.entrySet()) {
sb.append(PREFIX);
sb.append(BOUNDARY);
sb.append(LINEND);
sb.append("Content-Disposition: form-data; name=\"" + entry.getKey() + "\"" + LINEND);
sb.append("Content-Type: text/plain; charset=" + CHARSET + LINEND);
sb.append("Content-Transfer-Encoding: 8bit" + LINEND);
sb.append(LINEND);
sb.append(entry.getValue());
sb.append(LINEND);
}
DataOutputStream outStream = new DataOutputStream(conn.getOutputStream());
outStream.write(sb.toString().getBytes()); // 发送文件数据
if (files != null) for (Map.Entry<String, File> file : files.entrySet()) {
StringBuilder sb1 = new StringBuilder();
sb1.append(PREFIX);
sb1.append(BOUNDARY);
sb1.append(LINEND);
sb1.append("Content-Disposition: form-data; name=\"uploadfile\"; filename=\""
+ file.getValue().getName() + "\"" + LINEND);
sb1.append("Content-Type: application/octet-stream; charset=" + CHARSET + LINEND);
sb1.append(LINEND);
outStream.write(sb1.toString().getBytes());
InputStream is = new FileInputStream(file.getValue()); byte[] buffer = new byte[1024]; int len = 0; while ((len = is.read(buffer)) != -1) {
outStream.write(buffer, 0, len);
}
is.close();
outStream.write(LINEND.getBytes());
} byte[] end_data = (PREFIX + BOUNDARY + PREFIX + LINEND).getBytes();
outStream.write(end_data);
outStream.flush(); int res = conn.getResponseCode();
InputStream in = conn.getInputStream();
StringBuilder sb2 = new StringBuilder(); if (res == 200) { int ch; while ((ch = in.read()) != -1) {
sb2.append((char) ch);
}
}
outStream.close();
conn.disconnect(); return sb2.toString();
} // 测试
public static void main(String[] args) throws IOException {
String requestURL = "sss"; final Map<String, String> params = new HashMap<String, String>();
params.put("send_userId", String.valueOf(1));
params.put("send_email", "ss@ss.com"); final Map<String, File> files = new HashMap<String, File>();
files.put("uploadfile", new File("/var/data/de.jpg")); final String result = UploadUtil.post(requestURL, params, files);
System.out.println("result is: " + result);
}
}
二、php服务端接收文件，临时保存并继续上传至java后端：
1. 接收文件类
<?php
namespace App\Controller;use Action\RestAction;use Api\UploadApi;class UserController extends RestAction
{ /**
* 用户头像上传 */
public function set_avatar_post($code)
{ $uploadApi = new UploadApi(); $res = $uploadApi->uploads('avatar'); $filename = $res['data']; $result = $uploadApi->uploadAvatar($code, $filename);
@unlink($filename); //删除图片
if (!$result['status']) { $this->response($result);
} $avatar = A("Personal", "Api")->getAvatar($code); $this->response($avatar);
}
}
2. 上传类
<?php
namespace Api\Action;class UploadApi
{
public function __construct()
{ //... } public function curlGet($url, $param = array(), $timeout = 30, $ajaxResponseImmediately = true)
{ $opts = array(
CURLOPT_TIMEOUT => $timeout,
CURLOPT_RETURNTRANSFER => 1,
CURLOPT_SSL_VERIFYPEER => false,
CURLOPT_SSL_VERIFYHOST => false,
CURLOPT_HTTPHEADER => $header
); switch (strtoupper($method)) { // case 'POST':
// $opts[CURLOPT_URL] = $url;
// $opts[CURLOPT_POST] = 1;
// $opts[CURLOPT_POSTFIELDS] = $param;
// break;
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