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: public class Blogrunning { 23:
24: private List<String> cookies;
25: private HttpURLConnection conn;
26:
27: private final String USER_AGENT = "Mozilla/5.0";
28:
29: /**
30: * @param args
31: * @throws Exception
32: */
33: public static void main(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 = new Blogrunning();
38:
39: CookieHandler.setDefault(new CookieManager());
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: private void sendPost(String url, String postParams) throws IOException { 52: URL obj = new URL(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+);
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 = new DataOutputStream(conn.getOutputStream());
75: wr.writeBytes(postParams);
76: wr.flush();
77: wr.close();
78:
79: int responseCode = 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: BufferedReader in =
85: new BufferedReader(new InputStreamReader(conn.getInputStream()));
86: String inputLine;
87: StringBuffer response = new StringBuffer();
88:
89: while ((inputLine = in.readLine()) != null) { 90: response.append(inputLine);
91: }
92: in.close();
93: }
94: private String 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 = new ArrayList<String>();
102: for (Element inputElement : inputElements) { 103: String key = inputElement.attr("id"); 104: String value = inputElement.attr("value"); 105: if (key.equals("input1")) 106: value = username;
107: else if (key.equals("input2")) 108: value = password;
109: else if (key.equals("remember_me")); 110: value = "true";
111: paramList.add(key + "=" + URLEncoder.encode(value, "UTF-8"));
112: }
113:
114: StringBuilder result = new StringBuilder();
115: for (String param : paramList) { 116: if (result.length() == 0) { 117: result.append(param);
118: } else { 119: result.append("&" + param); 120: }
121: }
122: return result.toString();
123: }
124:
125: public List<String> getCookies() { 126: return cookies;
127: }
128:
129: public void setCookies(List<String> cookies) { 130: this.cookies = cookies;
131: }
132: private String GetPageContent(String url) throws Exception { 133: URL obj = new URL(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+);
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: int responseCode = conn.getResponseCode();
152: System.out.println("\nSending 'GET' request to URL : " + url); 153: System.out.println("Response Code : " + responseCode); 154:
155: BufferedReader in =
156: new BufferedReader(new InputStreamReader(conn.getInputStream()));
157: String inputLine;
158: StringBuffer response = new StringBuffer();
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: return response.toString();
169: }
170:
171: }
原标题：java访问需要登录后才能访问的页面一待续
关键词：JAVA
我知道了 