一.最近做阿里云oss文件上传开发，一点收获分享给大家，帮助大家绕过一些坑。关于阿里云oss服务的介绍，我这里不做赘述了，可以查看阿里云OSS开发api文档。
在这里我主要介绍下，文件上传流程比较复杂的服务器设置回调功能。整个流程图是这样的：
大家可以参考阿里api文档介绍的工作流程说明：https://help.aliyun.com/document_detail/31927.html?spm=5176.doc31988.6.633.OTY557
二. 客户端请求policy，签名，key以及回调地址等
1.首先定义我们的业务类型biz_type，主要是将文件按业务类型目录存储。这里我要着重强调一下，阿里oss回调请求的自定义参数：
${x:biz_type}，不要使用驼峰法命名，在开发的工程中，发现驼峰法命名bizType 取不到值。建议需要命名时 用"_"取代。
2.accessId ，accesskey 定义在properties文件中，这些定值从文件中读取，这里我要说明下：定义的end 和 endPoint
endpoint = http://oss-cn-shanghai.aliyuncs.com
end = oss-cn-shanghai.aliyuncs.com
bucket 是定义的桶名称就类似于文件目录名称。
2. callbackurl 定义自己的回调方法
3.签名，失效时间，policy，这些是根据阿里云官网提供的案例代码写的。
4.在定义callback字符串时，遇到一个大坑，这也是我写整篇文章的原因。
定义callback 时，阿里支持两种方式，一个是callbackBody字符串直接拼接 用&符连接。
这里我使用的是第二种方式，callbackBody 采用json字符串。但是这跟以往的字符串不一样，中间有阿里自带的字符bucket,object,size等以及自定义的字符，ali oss 需要解析自定义字符，这里可以理解成
变量的一个占位符，那么json串是如何拼接一个占位符变量呢？？？带着这个问题，我就一遍一遍的拼串，尝试了大概有两小时，看了官网的一篇错误排查文章：https://yq.aliyun.com/articles/68863/
定义的回调字符串是这样的：
{
"callbackUrl" : "http://abc.com/test.php",
"callbackHost" : "oss-cn-hangzhou.aliyuncs.com",
"callbackBody" : "{\"bucket\":${mimeType}, \"object\":${object},\"size\":${size},\"mimeType\":${mimeType},\"my_var\":${x:my_var}}",
"callbackBodyType" : "application/json"
}
顿时眼睛亮了，callbackBody 定义的原来是一个字符串的jsonobject,一直以为需要定义一个占位符类型的jsonobject对象。
然后继续拼串，定义的callbackBody就是这样： "{\'bucket\':${bucket}, \'object\':${object},\'size\':${size},\'mimeType\':${mimeType},\'uid\':${x:uid},\'biz_type\':${x:biz_type}}"
最终将 resMap 转成json 字符返回。1 public String reqOssServer() throws ServletException, IOException {
2
3 String[] bizArray = new String[]{"","user-dir/","advise-dir/"};
4
5 String biz_type = getRequest().getParameter("biz_type");
6
7 String sysCurrtime = System.currentTimeMillis()+"";
8
9 //15位随机码
10 String randStr = sysCurrtime.substring(5,sysCurrtime.length())+CommonUtil.getRamdon(15);
11 //目录
12 String dir = bizArray[Integer.valueOf(biz_type)];
13
14 PropertiesUtil pro = new PropertiesUtil("oss.properties");
15 String end = pro.readValue("end");
16 String endpoint = pro.readValue("endpoint");
17 String accessId = pro.readValue("accessKeyId");
18 String accessKey = pro.readValue("accessKeySecret");
19 String bucket = pro.readValue("bucketName");
20
21 String host = "https://" + bucket + "." + end;
23
24 //oss 回调地址
25 String callbackurl = Cont.TEST_DOMAIN_NAME+"/osscallback";
26
27 OSSClient client = new OSSClient(endpoint, accessId, accessKey);
28 try {
29 long expireTime = 3000;
30 long expireEndTime = System.currentTimeMillis() + expireTime * 100;
31 Date expiration = new Date(expireEndTime);
32 PolicyConditions policyConds = new PolicyConditions();
33 policyConds.addConditionItem(PolicyConditions.COND_CONTENT_LENGTH_RANGE, 0, 1048576000);
34 policyConds.addConditionItem(MatchMode.StartWith, PolicyConditions.COND_KEY, dir);
35
36 String postPolicy = client.generatePostPolicy(expiration, policyConds);
37 byte[] binaryData = postPolicy.getBytes("utf-8");
38 String encodedPolicy = BinaryUtil.toBase64String(binaryData);
39 String postSignature = client.calculatePostSignature(postPolicy);
40
41
42 Map<String, String> respMap = new LinkedHashMap<String, String>();
43 URL url = client.generatePresignedUrl(bucket, accessKey, expiration);
44 respMap.put("accessid", accessId);
45 respMap.put("policy", encodedPolicy);
46 respMap.put("signature", postSignature);
47 //respMap.put("expire", formatISO8601Date(expiration));
48 respMap.put("dir", dir);
49 respMap.put("host", host);
50 respMap.put("expire", String.valueOf(expireEndTime / 1000));
51 respMap.put("url", url.toString());
52 respMap.put("key", randStr);
53 //bucket=${bucket}&object=${object}&etag=${etag}&size=${size}&mimeType=${mimeType}&my_var=${x:my_var}
54 /* String callback = "{\"callbackUrl\":\"" + callbackurl + "\",\"callbackBody\":\"filename=${object}&size=${size}&mimeType=${mimeType}&"
55 + "orderid=" + orderid + "&calbackright=" + calbackright + "\",\"callbackBodyType\":\"application/x-www-form-urlencoded\"}";*/
56 //先传入一个固定值测试
57 // String callback = "{\"callbackUrl\":\"" + callbackurl + "\",\"callbackBody\":\"filename=${object}&size=${size}&mimeType=${mimeType}&orderid=123\",\"callbackBodyType\":\"application/x-www-form-urlencoded\"}";
58
59 //String callback = "{\"callbackUrl\":\""+callbackurl+"\",\"callbackBody\":\"{\'bucket\':${bucket}, \'object\':${object},\'size\':${size},\'mimeType\':${mimeType},\'uid\':${x:uid}}\",\"callbackBodyType\":\"application/json\"}";
60
61 String callbackbody = "{\'bucket\':${bucket}, \'object\':${object},\'size\':${size},\'mimeType\':${mimeType},\'uid\':${x:uid},\'biz_type\':${x:biz_type}}";
62 if("1".equals(biz_type)){//用户头像，banner修改
63 callbackbody = "{\'bucket\':${bucket}, \'object\':${object},\'size\':${size},\'mimeType\':${mimeType},\'uid\':${x:uid},\'biz_type\':${x:biz_type},\'portrait\':${x:portrait},\'banner\':${x:banner}}";
64 }else if("2".equals(biz_type)){//投诉建议
65 callbackbody = "{\'bucket\':${bucket}, \'object\':${object},\'size\':${size},\'mimeType\':${mimeType},\'uid\':${x:uid},\'biz_type\':${x:biz_type},\'path\':${x:path},\'guideid\':${x:guideid}}";
66 }
67
68 String callback = "{\"callbackUrl\":\""+callbackurl+"\",\"callbackBody\":\""+callbackbody+"\",\"callbackBodyType\":\"application/json\"}";
69
70 byte[] bytes = Base64.encodeBase64(callback.getBytes("UTF-8"));
71 respMap.put("callback", new String(bytes));
72 //respMap.put("callback_str", callback);
73 JSONObject ja1 = JSONObject.fromObject(respMap);
74 System.out.println("=====respMap:===== "+ja1.toString());
75 getResponse().setHeader("Access-Control-Allow-Origin", "*");
76 getResponse().setHeader("Access-Control-Allow-Methods", "GET, POST");
77
78 setJsonString(AppJSON.succReq("请求成功", ja1.toString()));
79 } catch (Exception e) {
80 Assert.fail(e.getMessage());
81 }
82
83 return "ajax";
84 }
三. 回调方法处理业务逻辑
该回调方法是一个servlet，需要在web.xml中配置 访问的路径地址。在servlet中，主要进行业务处理，这里就不在贴出我的业务处理了，大家根据自己的实际需要进行编码。
1 package com.zd.servlet;
2 import java.io.BufferedReader;
3 import java.io.IOException;
4 import java.io.InputStream;
5 import java.io.InputStreamReader;
6 import java.net.URI;
7 import java.net.URL;
8 import java.security.KeyFactory;
9 import java.security.PublicKey;
10 import java.security.spec.X509EncodedKeySpec;
11 import java.text.ParseException;
12 import java.util.Date;
13 import javax.servlet.ServletException;
14 import javax.servlet.annotation.WebServlet;
15 import javax.servlet.http.HttpServlet;
16 import javax.servlet.http.HttpServletRequest;
17 import javax.servlet.http.HttpServletResponse;
18 import net.sf.json.JSONObject;
19 import org.apache.commons.lang.StringUtils;
20 import org.apache.http.HttpResponse;
21 import org.apache.http.client.methods.HttpGet;
22 import org.apache.http.impl.client.DefaultHttpClient;
23 import com.aliyun.oss.common.utils.BinaryUtil;
24 import com.zd.aliyun.oss.HttpMethod;
25 import com.zd.aliyun.oss.OSSClient;
26 import com.zd.aliyun.oss.common.utils.DateUtil;
27 import com.zd.aliyun.oss.model.GeneratePresignedUrlRequest;
28 import com.zd.util.Cont;
29 import com.zd.util.FileUtil;
30 import com.zd.util.StringUtil;
31 import com.zd.util.codeBuild.PropertiesUtil;
32
33
34 @SuppressWarnings("deprecation")
35 @WebServlet(asyncSupported = true)
36 public class OssCallBackService extends HttpServlet {
37 protected void doGet(HttpServletRequest req, HttpServletResponse resp)
38 throws ServletException, IOException {
39 this.doPost(req, resp);
40 response(req, resp, "input get ", 200);
41 }
44
45 @SuppressWarnings({ "finally" })
46 public String executeGet(String url) {
47 BufferedReader in = null;
49 String content = null;
50 try {
51 // 定义HttpClient
52 @SuppressWarnings("resource")
53 DefaultHttpClient client = new DefaultHttpClient();
54 // 实例化HTTP方法
55 HttpGet request = new HttpGet();
56 request.setURI(new URI(url));
57 HttpResponse response = client.execute(request);
58
59 in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
60 StringBuffer sb = new StringBuffer("");
61 String line = "";
62 String NL = System.getProperty("line.separator");
63 while ((line = in.readLine()) != null) {
64 sb.append(line + NL);
65 }
66 in.close();
67 content = sb.toString();
68 } catch (Exception e) {
69 } finally {
70 if (in != null) {
71 try {
72 in.close();// 最后要关闭BufferedReader
73 } catch (Exception e) {
74 e.printStackTrace();
75 }
76 }
77 return content;
78 }
79 }
80
81 public String GetPostBody(InputStream is, int contentLen) {
82 if (contentLen > 0) {
83 int readLen = 0;
84 int readLengthThisTime = 0;
85 byte[] message = new byte[contentLen];
86 try {
87 while (readLen != contentLen) {
88 readLengthThisTime = is.read(message, readLen, contentLen - readLen);
89 if (readLengthThisTime == -1) {// Should not happen.
90 break;
91 }
92 readLen += readLengthThisTime;
93 }
94 return new String(message);
95 } catch (IOException e) {
96 }
97 }
98 return "";
99 }
100
101 //oss回调请求
102 protected boolean VerifyOSSCallbackRequest(HttpServletRequest request, String ossCallbackBody) throws NumberFormatException, IOException
103 {
104 boolean ret = false;
105 String autorizationInput = new String(request.getHeader("Authorization"));
106 String pubKeyInput = request.getHeader("x-oss-pub-key-url");
107 byte[] authorization = BinaryUtil.fromBase64String(autorizationInput);
108 byte[] pubKey = BinaryUtil.fromBase64String(pubKeyInput);
109 String pubKeyAddr = new String(pubKey);
110 if (!pubKeyAddr.startsWith("http://gosspublic.alicdn.com/") && !pubKeyAddr.startsWith("https://gosspublic.alicdn.com/"))
111 {
112 System.out.println("pub key addr must be oss addrss");
113 return false;
114 }
115 String retString = executeGet(pubKeyAddr);
116 retString = retString.replace("-----BEGIN PUBLIC KEY-----", "");
117 retString = retString.replace("-----END PUBLIC KEY-----", "");
118 String queryString = request.getQueryString();
119 String uri = request.getRequestURI();
120 String decodeUri = java.net.URLDecoder.decode(uri, "UTF-8");
121 String authStr = decodeUri;
122 if (queryString != null && !queryString.equals("")) {
123 authStr += "?" + queryString;
124 }
125 authStr += "\n" + ossCallbackBody;
126 ret = doCheck(authStr, authorization, retString);
127 return ret;
128 }
129
130
131 protected void doPost(HttpServletRequest request, HttpServletResponse response)
132 throws ServletException, IOException {
133 //HttpServletRequest
134 String ossCallbackBody = GetPostBody(request.getInputStream(), Integer.parseInt((request).getHeader("content-length")));
135 System.out.println("ossCallbackBody == "+ossCallbackBody);
136
137 boolean ret = VerifyOSSCallbackRequest(request, ossCallbackBody);
138 System.out.println("verify result:" + ret);
139
140 // String aaa ="{\"bucket\":\"picture-zoomdu\",\"object\":\"2017072131713.jpg\",\"size\":\"12345\","gid":"86","uid":"121","type":"1"}
141 JSONObject obj = JSONObject.fromObject(ossCallbackBody);
142 PropertiesUtil pro = new PropertiesUtil("oss.properties");
143 String endpoint = pro.readValue("endpoint");
144 String accessKeyId = pro.readValue("accessKeyId");
145 String accessKeySecret = pro.readValue("accessKeySecret");
146
147 String bucketName = obj.get("bucket").toString();
148 String bucketkey = obj.get("object").toString();
149
150 OSSClient ossClient = new OSSClient(endpoint, accessKeyId, accessKeySecret);
151 Date expirations = null;
152 try {
153 expirations = DateUtil.parseRfc822Date("Wed, 18 Mar 2019 14:20:00 GMT");
154 } catch (ParseException e) {
155 e.printStackTrace();
156 }
157 GeneratePresignedUrlRequest requestGenerate = new GeneratePresignedUrlRequest(bucketName, bucketkey, HttpMethod.GET);
158 requestGenerate.setExpiration(expirations);
159
160 URL signedUrl = ossClient.generatePresignedUrl(requestGenerate);
161 String path =signedUrl.toString();
162 if(signedUrl.toString().indexOf("?")>-1){
163 path = path.substring(0,signedUrl.toString().indexOf("?"));
164 }
165 // 图片压缩配置的字符串
166 path += "?x-oss-process=style/zd_list_image";
167 String ossurl = "{\"ossurl\":\""+signedUrl.toString()+"\"}";
168 if (ret){//签名验证通过，业务处理
169 //客户端 在回调中需要 传入的字段
171
172 response(request, response, "{\"Status\":\"OK\"}", HttpServletResponse.SC_OK);
173 //业务处理..... 此处省略
174 if(obj.containsKey("uid") && StringUtils.isNotEmpty(obj.get("uid")+"")){
175 String uid = obj.get("uid").toString();
176 //biz_type : 1:用户头像、banner ,2:投诉建议图片上传220 }
221 }
222 else{
223 response(request, response, "{\"Status\":\"verdify not ok\"}", HttpServletResponse.SC_BAD_REQUEST);
224 }
226 }
227
229 public static boolean doCheck(String content, byte[] sign, String publicKey) {
230 try {
231 KeyFactory keyFactory = KeyFactory.getInstance("RSA");
232 byte[] encodedKey = BinaryUtil.fromBase64String(publicKey);
233 PublicKey pubKey = keyFactory.generatePublic(new X509EncodedKeySpec(encodedKey));
234 java.security.Signature signature = java.security.Signature.getInstance("MD5withRSA");
235 signature.initVerify(pubKey);
236 signature.update(content.getBytes());
237 boolean bverify = signature.verify(sign);
238 return bverify;
239
240 } catch (Exception e) {
241 e.printStackTrace();
242 }
243
244 return false;
245 }
246
247 private void response(HttpServletRequest request, HttpServletResponse response, String results, int status) throws IOException {
248 String callbackFunName = request.getParameter("callback");
249 System.out.println("callbackFunName:"+callbackFunName);
250 response.addHeader("Content-Length", String.valueOf(results.length()));
251 if (callbackFunName == null || callbackFunName.equalsIgnoreCase(""))
252 response.getWriter().println(results);
253 else
254 response.getWriter().println(callbackFunName + "( " + results + " )");
255 response.setStatus(status);
256 response.flushBuffer();
257 }
258
259 }
四.关于oss 上传，并设置回调就介绍到这里，本篇文章没有介绍，oss服务配置，主要是讲技术坑。如有什么问题，请留言联系我，很乐意解决大家的问题。
另外郑重说明，本篇文章是本人原创，如需转载 请标注转载原文地址。