HttpClient先post登陆,在get数据

我用的是httpclient-4.5.1.jar,如果httpclient版本太低的话,此方法可能用不了,需要用手工设置cookie.那种方法,暂不讨论,主要思路就是通过登陆时获取返回的cookie,再讲coolie的值填到新的请求头中,不过这种方法一般不怎么遇到,基本上对面接口都会直接返回给你一个token,你下次访问直接将这个token作为参数传过去就能获取自己想要的数据.

package test;

import java.util.Date;
import java.util.HashMap;
import java.util.Map;

import org.apache.http.HttpEntity;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

import com.alibaba.fastjson.JSONArray;

public class JKTest03 {


	public static void main(String[] args) throws Exception {
		long st=new Date().getTime();
		CloseableHttpClient http = HttpClients.createDefault();
		try {
			String url = "post";
			HashMap map = new HashMap();
			map.put("username", "admin");
			map.put("password", "pass");
			getlogin(http, map, url);//登陆验证
			String url2 = "get";
			String list = Get(http, url2);//获取数据
			System.out.println(list);
		} finally {
			http.close();
		}
		long et=new Date().getTime();
		System.out.println("共费时:"+(et-st));
		// System.out.println("结束");
	}

	public static String getlogin(CloseableHttpClient client, Map map, String url) throws Exception {
		String body = "";
		String encoding = "utf-8";
		// 创建post方式请求对象
		HttpPost httpPost = new HttpPost(url);
		// 装填参数,常规格式
		/*
		 * List nvps = new ArrayList(); if (map != null) {
		 * for (Entry entry : map.entrySet()) {
		 * //System.out.println(entry.getKey()+"=="+ entry.getValue()); nvps.add(new
		 * BasicNameValuePair(entry.getKey(), entry.getValue())); } } // 设置参数到请求对象中
		 * httpPost.setEntity(new UrlEncodedFormEntity(nvps, encoding));
		 * // 设置参数到请求对象中
		  httpPost.setEntity(new UrlEncodedFormEntity(nvps, encoding));
		 */
		
		//参数是json格式
		httpPost.setEntity(new StringEntity(JSONArray.toJSONString(map)));
		// 设置header信息
		// 指定报文头【Content-type】、【User-Agent】
		//参数是json的需要将Content-type设为application/json
		httpPost.setHeader("Content-type", "application/json");//默认是:application/x-www-form-urlencoded
		httpPost.setHeader("User-Agent", "Mozilla/4.0 (compatible; MSIE 5.0; Windows NT; DigExt)");
		
		// 执行请求操作，并拿到结果（同步阻塞）
		CloseableHttpResponse response = client.execute(httpPost);
		// response.

		// 获取结果实体
		HttpEntity entity = response.getEntity();
		if (entity != null) {
			// 按指定编码转换结果实体为String类型
			body = EntityUtils.toString(entity, encoding);
		}
		
		// 释放链接
		response.close();
		return body;
	}
	public static String Get(CloseableHttpClient http, String url) throws Exception {
		HttpGet httpget = new HttpGet(url);

		String body = "";
		CloseableHttpResponse response = http.execute(httpget);
		// response.

		// 获取结果实体
		HttpEntity entity = response.getEntity();
		if (entity != null) {
			// 按指定编码转换结果实体为String类型
			body = EntityUtils.toString(entity, "utf-8");
		}
		// 释放链接
		response.close();
		return body;
	}
}