HttpClient 模拟登陆，保持会话并进行后续操作 | 隔叶黄莺 Yanbin Blog

2011-03-10 | 阅读(15,709)

Apache HttpClient 是很方便的 Java 开源的访问 HTTP 资源的组件。网站上的资源不总是能匿名访问的，很多都需要登陆后才能操作，且不说论坛里登陆后才能发言，就是某些稍显敏感的 XML 等信息也是登陆后才能获取到的。

没问题，HttpClient 能让你做到，它提供了 Basic 和 Form-Based 两种验证方式。登陆后获得服务器端发来的 Cookie 作为下一次访问的凭证, 让服务端认为你还是个合法用户。服务端不是用 Session 来维护会话的吗？是的，Session 也要有个载体，Cookie 了。或有时 Java Web 会用 jsessionid 参数在服务端与客户端来回关联 Session 信息，也没问题，HttpClient 同样能胜任。

下面主要说明 Form-Based 的验证方式，Basic 的验证简单列了几行代码，还未实践，具体可参考文后的链接。

看 Form-Based 方式的演示代码，如果登陆时需要一个验证码的话，那只有自己想办法怎么得到这个码了，登陆时谁都想无码：

package cc.unmi.httpclient; 

import org.apache.commons.httpclient.Cookie;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.NameValuePair;
import org.apache.commons.httpclient.cookie.CookiePolicy;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.httpclient.methods.PostMethod;
import org.junit.Test;

public class HttpClientLogin {

    public static void main(String[] args){
        //登陆 Url
        String loginUrl = "http://localhost/unmi/login.html";

        //需登陆后访问的 Url
        String dataUrl = "http://localhost/unmi/user_info.html?userid=123456";

        HttpClient httpClient = new HttpClient();

        //模拟登陆，按实际服务器端要求选用 Post 或 Get 请求方式
        PostMethod postMethod = new PostMethod(loginUrl);

        //设置登陆时要求的信息，一般就用户名和密码，验证码自己处理了
        NameValuePair[] data = {
                new NameValuePair("username", "Unmi"),
                new NameValuePair("password", "123456"),
                new NameValuePair("code", "anyany")
        };
        postMethod.setRequestBody(data);

        try {
            //设置 HttpClient 接收 Cookie,用与浏览器一样的策略
            httpClient.getParams().setCookiePolicy(CookiePolicy.BROWSER_COMPATIBILITY);
            httpClient.executeMethod(postMethod);

            //获得登陆后的 Cookie
            Cookie[] cookies=httpClient.getState().getCookies();
            String tmpcookies= "";
            for(Cookie c:cookies){
                tmpcookies += c.toString()+";";
            }

            //进行登陆后的操作
            GetMethod getMethod = new GetMethod(dataUrl);

            //每次访问需授权的网址时需带上前面的 cookie 作为通行证
            getMethod.setRequestHeader("cookie",tmpcookies);

            //你还可以通过 PostMethod/GetMethod 设置更多的请求后数据
            //例如，referer 从哪里来的，UA 像搜索引擎都会表名自己是谁，无良搜索引擎除外
            postMethod.setRequestHeader("Referer", "http://unmi.cc");
            postMethod.setRequestHeader("User-Agent","Unmi Spot");

            httpClient.executeMethod(getMethod);

            //打印出返回数据，检验一下是否成功
            String text = getMethod.getResponseBodyAsString();
            System.out.println(text);

        } catch (Exception e) {
            e.printStackTrace();
        }   
    }
}

package cc.unmi.httpclient;

import org.apache.commons.httpclient.Cookie;

import org.apache.commons.httpclient.HttpClient;

import org.apache.commons.httpclient.NameValuePair;

import org.apache.commons.httpclient.cookie.CookiePolicy;

import org.apache.commons.httpclient.methods.GetMethod;

import org.apache.commons.httpclient.methods.PostMethod;

import org.junit.Test;

public class HttpClientLogin {

public static void main(String[] args){

//登陆 Url

String loginUrl = "http://localhost/unmi/login.html";

//需登陆后访问的 Url

String dataUrl = "http://localhost/unmi/user_info.html?userid=123456";

HttpClient httpClient = new HttpClient();

//模拟登陆，按实际服务器端要求选用 Post 或 Get 请求方式

PostMethod postMethod = new PostMethod(loginUrl);

//设置登陆时要求的信息，一般就用户名和密码，验证码自己处理了

NameValuePair[] data = {

new NameValuePair("username", "Unmi"),

new NameValuePair("password", "123456"),

new NameValuePair("code", "anyany")

};

postMethod.setRequestBody(data);

try {

//设置 HttpClient 接收 Cookie,用与浏览器一样的策略

httpClient.getParams().setCookiePolicy(CookiePolicy.BROWSER_COMPATIBILITY);

httpClient.executeMethod(postMethod);

//获得登陆后的 Cookie

Cookie[] cookies=httpClient.getState().getCookies();

String tmpcookies= "";

for(Cookie c:cookies){

tmpcookies += c.toString()+";";

}

//进行登陆后的操作

GetMethod getMethod = new GetMethod(dataUrl);

//每次访问需授权的网址时需带上前面的 cookie 作为通行证

getMethod.setRequestHeader("cookie",tmpcookies);

//你还可以通过 PostMethod/GetMethod 设置更多的请求后数据

//例如，referer 从哪里来的，UA 像搜索引擎都会表名自己是谁，无良搜索引擎除外

postMethod.setRequestHeader("Referer", "http://unmi.cc");

postMethod.setRequestHeader("User-Agent","Unmi Spot");

httpClient.executeMethod(getMethod);

//打印出返回数据，检验一下是否成功

String text = getMethod.getResponseBodyAsString();

System.out.println(text);

} catch (Exception e) {

e.printStackTrace();

}

Basic 验证的简单代码导引，还未亲试：

HttpClient client = new HttpClient();

// 1
client.getState().setCredentials(
    new AuthScope("unmi.cc", 80, AuthScope.ANY_REALM),
    new UsernamePasswordCredentials("username", "password")
);

// 2
client.getParams().setAuthenticationPreemptive(true);

// 3
GetMethod getMothod = new GetMethod("http://yanbin.blog/twitter");

// 4
getMothod.setDoAuthentication( true );

// 5
int status = client.executeMethod( getMothod );

HttpClient client = new HttpClient();

// 1

client.getState().setCredentials(

new AuthScope("unmi.cc", 80, AuthScope.ANY_REALM),

new UsernamePasswordCredentials("username", "password")

);

// 2

client.getParams().setAuthenticationPreemptive(true);

// 3

GetMethod getMothod = new GetMethod("http://yanbin.blog/twitter");

// 4

getMothod.setDoAuthentication( true );

// 5

int status = client.executeMethod( getMothod );

参考：1. ZT---httpclient如何保持session会话模拟登录后的操作
2. 使用 Apache HttpClient 突破 J2EE 站点认证
3. 官方例子，BasicAuthenticationExample.java

本文链接 https://yanbin.blog/httpclient-login-session/, 来自隔叶黄莺 Yanbin Blog

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