详解Java实现多种方式的http数据抓取

前言：

时下互联网第一波的浪潮已消逝，随着而来的基于万千数据的物联网时代，因而数据成为企业的重要战略资源之一。基于数据抓取技术，本文介绍了java相关抓取工具，并附上demo源码供感兴趣的朋友测试！

1）JDK自带HTTP连接，获取页面或Json

2） JDK自带URL连接，获取页面或Json

3）HttpClient Get工具，获取页面或Json

 4）commons-io工具，获取页面或Json

5） Jsoup工具（通常用于html字段解析），获取页面,非Json返回格式】

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完整代码：

package com.yeezhao.common.http;

import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpMethod;
import org.apache.commons.httpclient.methods.GetMethod;
import org.apache.commons.io.IOUtils;
import org.jsoup.Jsoup;


public class HttpFetchUtil {
  
  
  public static int getResponseCode(String request) throws Exception {
    URL url = new URL(request);
    HttpURLConnection conn = (HttpURLConnection) url.openConnection();
    return conn.getResponseCode();

  }
  
  public static String JDKFetch(String request, String charset) throws Exception {
    URL url = new URL(request);
    HttpURLConnection conn = (HttpURLConnection) url.openConnection();
    //模拟浏览器参数
    conn.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36"
 + " (KHTML, like Gecko) Chrome/45.0.2454.101 Safari/537.36");
    if (conn.getResponseCode() == HttpURLConnection.HTTP_OK) {
      InputStream input = conn.getInputStream();
      StringBuffer sb = new StringBuffer();
      BufferedReader reader = new BufferedReader(new InputStreamReader(input, charset));
      String s;
      while ((s = reader.readLine()) != null) {
 sb.append(s + "n");
      }
      input.close();
      conn.disconnect();
      return sb.toString();
    }
    return "";
  }
  
  public static String URLFetch(String request, String charset) throws Exception {
    URL url = new URL(request);
    return IOUtils.toString(url.openStream());
  }

  
  public static String httpClientFetch(String url, String charset) throws Exception {
    // GET
    HttpClient httpClient = new HttpClient();
    httpClient.getParams().setContentCharset(charset);
    HttpMethod method = new GetMethod(url);
    httpClient.executeMethod(method);
    return method.getResponseBodyAsString();
  }
  
  public static String commonsIOFetch(String url, String charset) throws Exception {
    return IOUtils.toString(new URL(url), charset);
  }
  
  
  public static String jsoupFetch(String url) throws Exception {
    return Jsoup.parse(new URL(url), 2 * 1000).html();
  }

}

测试代码：

package com.yeezhao.common.http;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;

public class HttpFetchUtilTest {
  String seeds[] = {"http://baike.baidu.com/view/1.htm","http://m.ximalaya.com/tracks/26096131.json","http://remyapi.yeezhao.com/api/query?wd=%E5%91%A8%E6%98%9F%E9%A9%B0%E7%9A%84%E7%94%B5%E5%BD%B1"};
  final static String DEFAULT_CHARSET = "UTF-8";
  @Before
  public void setUp() throws Exception {
  }

  @After
  public void tearDown() throws Exception {
    System.out.println("--- down ---");
  }

  @Test
  public void testGetResponseCode() throws Exception{
    for(String seed:seeds){
      int responseCode = HttpFetchUtil.getResponseCode(seed);
      System.out.println("ret="+responseCode);
    }
  }

  @Test
  public void testJDKFetch() throws Exception{
    for(String seed:seeds){
      String ret = HttpFetchUtil.JDKFetch(seed, DEFAULT_CHARSET);
      System.out.println("ret="+ret);
    }
  }

  @Test
  public void testURLFetch() throws Exception{
    for(String seed:seeds){
      String ret = HttpFetchUtil.URLFetch(seed, DEFAULT_CHARSET);
      System.out.println("ret="+ret);
    }
  }

  @Test
  public void testHttpClientFetch()throws Exception {
    for(String seed:seeds){
      String ret = HttpFetchUtil.httpClientFetch(seed, DEFAULT_CHARSET);
      System.out.println("ret="+ret);
    }
  }

  @Test
  public void testCommonsIOFetch()throws Exception {
    for(String seed:seeds){
      String ret = HttpFetchUtil.commonsIOFetch(seed, DEFAULT_CHARSET);
      System.out.println("ret="+ret);
    }
  }

  @Test
  public void testJsoupFetch() throws Exception{
    for(String seed:seeds){
      String ret = HttpFetchUtil.jsoupFetch(seed);
      System.out.println("ret="+ret);
    }
  }

}

附：相关jar依赖

...

org.jsoup
jsoup
1.7.3



commons-httpclient
commons-httpclient
3.1



commons-io
commons-io
2.4

...

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