java访问需要登录后才能访问的页面一待续
我们平时所访问的页面有的仅仅是一些普通的页面，有的需要用户登录后方可使用，或者需要认证以及是一些通过加密方式传输，例如HTTPS。很多页面需要我们注册登录后才能访问，这个时候就涉及到cookie的处理问题，为了使我们的程序能使用别人所提供的服务页面，就要求程序首先登录后再访问服务页面，这过程就需 要自行处理cookie。原文地址http://www.yihaomen.com/article/java/371.htm
大概分为3个步骤
第一步 发送一个Get请求 String page = http.GetPageContent(url); 其实就是为了获取到一个访问的Document将流转化为字符串，方便访问。
第二步 在发送post请求时需要发送对应的用户名密码，这个也是关键所在，因为一般不是你开发的网站你不清楚要传递的参数名是什么，通过Jsoup解析网页，循环遍历其中的input控件，将需要的用户名密码拼接起来，类似邮箱就是u=username&p=passWord
第三步 发送post请求，将拼接的字符串作为流读进去
第四步 读取cookie，带着cookie一起访问下一个需要登录后访问的页面
最后 未成功访问，估计错误在第二步，路过的请提宝贵意见，直接上代码
1:package BlogTest;
2:
3:import java.io.BufferedReader;
4:import java.io.DataOutputStream;
5:import java.io.IOException;
6:import java.io.InputStreamReader;
7:import java.io.UnsupportedEncodingException;
8:import java.net.CookieHandler;
9:import java.net.CookieManager;
10:import java.net.URL;
11:import java.net.URLEncoder;
12:import java.util.ArrayList;
13:import java.util.List;
14:
15:import org.jsoup.Jsoup;
16:import org.jsoup.nodes.Document;
17:import org.jsoup.nodes.Element;
18:import org.jsoup.select.Elements;
19:
20:import sun.net.www.PRotocol.http.HttpURLConnection;
21:
22:publicclassBlogrunning {
23:
24:privateList<String> cookies;
25:privateHttpURLConnection conn;
26:
27:privatefinal String USER_AGENT ="Mozilla/5.0";
28:
29:/**
30:* @param args
31:* @throws Exception
32:*/
33:publicstaticvoidmain(String[] args) throws Exception {
34:String url ="http://passport.cnblogs.com/user/signin";
35:String redirturl ="http://home.cnblogs.com/u/Sir-Lin/followers/1/";
36:
37:Blogrunning http =newBlogrunning();
38:
39:CookieHandler.setDefault(newCookieManager());
40:
41:// 1. 发送get请求
42:String page = http.GetPageContent(url);
43:String postParams = http.getFormParams(page,"username","password");
44:// 2. 发送post请求
45:http.sendPost(url, postParams);
46:
47:// 3. success
48:String result = http.GetPageContent(redirturl);
49:System.out.println(result);
50:}
51:privatevoidsendPost(String url, String postParams) throws IOException {
52:URL obj =newURL(url);
53:conn = (HttpURLConnection) obj.openConnection();
54:
55:conn.setUseCaches(false);
56:conn.setRequestMethod("POST");
57:conn.setRequestProperty("Host","passport.cnblogs.com");
58:conn.setRequestProperty("User-Agent", USER_AGENT);
59:conn.setRequestProperty("Accept",
60:"text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
61:conn.setRequestProperty("Accept-Language","en-US,en;q=0.5");
62:for(String cookie :this.cookies) {
63:conn.addRequestProperty("Cookie", cookie.split(";", 1)[0]);
64:}
65:conn.setRequestProperty("Connection","keep-alive");
66:conn.setRequestProperty("Referer","http://passport.cnblogs.com/user/signin");
67:conn.setRequestProperty("Content-Type","application/x-www-form-urlencoded");
68:conn.setRequestProperty("Content-Length", Integer.toString(postParams.length()));
69:
70:conn.setDoOutput(true);
71:conn.setDoInput(true);
72:
73://发送post请求
74:DataOutputStream wr =newDataOutputStream(conn.getOutputStream());
75:wr.writeBytes(postParams);
76:wr.flush();
77:wr.close();
78:
79:intresponseCode = conn.getResponseCode();
80:System.out.println("\nSending 'POST' request to URL : "+ url);
81:System.out.println("Post parameters : "+ postParams);
82:System.out.println("Response Code : "+ responseCode);
83:
84:BufferedReaderin=
85:newBufferedReader(newInputStreamReader(conn.getInputStream()));
86:String inputLine;
87:StringBuffer response =newStringBuffer();
88:
89:while((inputLine =in.readLine()) !=null) {
90:response.append(inputLine);
91:}
92:in.close();
93:}
94:privateString getFormParams(String html, String username, String password) throws UnsupportedEncodingException {
95:System.out.println("Extracting form's data...");
96:
97:Document doc = Jsoup.parse(html);
98:
99:Element loginform = doc.getElementById("Main");
100:Elements inputElements = loginform.getElementsByTag("input");
101:List<String> paramList =newArrayList<String>();
102:for(Element inputElement : inputElements) {
103:String key = inputElement.attr("id");
104:Stringvalue= inputElement.attr("value");
105:if(key.equals("input1"))
106:value= username;
107:elseif(key.equals("input2"))
108:value= password;
109:elseif(key.equals("remember_me"));
110:value="true";
111:paramList.add(key +"="+ URLEncoder.encode(value,"UTF-8"));
112:}
113:
114:StringBuilder result =newStringBuilder();
115:for(String param : paramList) {
116:if(result.length() == 0) {
117:result.append(param);
118:}else{
119:result.append("&"+ param);
120:}
121:}
122:returnresult.toString();
123:}
124:
125:publicList<String> getCookies() {
126:returncookies;
127:}
128:
129:publicvoidsetCookies(List<String> cookies) {
130:this.cookies = cookies;
131:}
132:privateString GetPageContent(String url) throws Exception {
133:URL obj =newURL(url);
134:conn = (HttpURLConnection) obj.openConnection();
135:
136:conn.setRequestMethod("GET");
137:
138:conn.setUseCaches(false);
139:
140:conn.setRequestProperty("User-Agent", USER_AGENT);
141:conn.setRequestProperty("Accept",
142:"text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8");
143:conn.setRequestProperty("Accept-Language","zh-CN,zh;q=0.5");
144:if(cookies !=null) {
145:for(String cookie :this.cookies) {
146:conn.addRequestProperty("Cookie", cookie.split(";",1)[0]);
147:System.out.println("cookie: "+cookie.split(";",1)[0]);
148:}
149:}
150:
151:intresponseCode = conn.getResponseCode();
152:System.out.println("\nSending 'GET' request to URL : "+ url);
153:System.out.println("Response Code : "+ responseCode);
154:
155:BufferedReaderin=
156:newBufferedReader(newInputStreamReader(conn.getInputStream()));
157:String inputLine;
158:StringBuffer response =newStringBuffer();
159:
160:while((inputLine =in.readLine()) !=null) {
161:response.append(inputLine);
162:}
163:in.close();
164:
165:// Get the response cookies
166:setCookies(conn.getHeaderFields().get("Set-Cookie"));
167:
168:returnresponse.toString();
169:}
170:
171:}