1.本文宗旨
记录日常所用并与网友分享
2.httpClient、jsoup、okhttp、junitHtml能干什么
用来发送或者接受http请求，或者说能够抓取网页爬去信息，就是java版的爬虫.
3.httpClient、okhttp、restTemplate收发请求
3.1httpClient的get请求
/**
* httpClient的get请求介绍
*/
@Test
public void getHtmlPost(){
// 创建默认的httpClient实例.
String url = "https://search.17k.com/search.xhtml";
Map<String,Object> map = new HashMap<>();
map.put("c.st",0);
map.put("c.q","近战狂兵");
url = setDoGetUrl(url,map);
RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(120000).setSocketTimeout(60000)
.setConnectionRequestTimeout(60000).build();
CloseableHttpClient httpclient;
HttpClientContext httpClientContext = HttpClientContext.create();
CookieStore cookieStore = null;
cookieStore = new BasicCookieStore();
httpclient = HttpClientBuilder.create().setKeepAliveStrategy(new DefaultConnectionKeepAliveStrategy())
.setRedirectStrategy(new DefaultRedirectStrategy()).setDefaultRequestConfig(requestConfig)
.setDefaultCookieStore(cookieStore).build();
Function<Object,Object> function=null;
String resGet = doGet(url,map,httpclient,httpClientContext);
}
private String doGet(String url) {
return doGet(url,null,null,null);
}
private String doGet(String url,CloseableHttpClient httpclient, HttpClientContext httpClientContext) {
return doGet(url,null,httpclient,httpClientContext);
}
/*
* get请求方法封装
*/
private String doGet(String url, Map map, CloseableHttpClient httpclient, HttpClientContext httpClientContext) {
if(httpclient==null) httpclient = HttpClients.createDefault();
if(httpClientContext==null)httpClientContext = HttpClientContext.create();
setDoGetUrl(url,map);
CookieStore cookieStore223 = httpClientContext.getCookieStore();
if(cookieStore223!=null){
System.out.println("===============================什么这里有cookie====================");
List<Cookie> listCookie = cookieStore223.getCookies();
System.out.println(listCookie);
}
String web="";
HttpGet httpget = new HttpGet(url);
CloseableHttpResponse response = null;
httpget.setHeader("Connection", "close");//请求头设置
httpget.setHeader("Content-Encoding", "gzip");
httpget.setHeader("Server", "openresty");
httpget.setHeader("Transfer-Encoding", "chunked");
httpget.setHeader("Vary", "Accept-Encoding");
httpget.setHeader("Content-Type","text/html;charset=UTF-8");
try {
//这一步很重要，如果只传一个参数就是普通的get请求，如果是带了httpClientContext上下文没那么可以将多次请求维持在同一session里面，前提是别关闭httpClient
response = httpclient.execute(httpget,httpClientContext);
HttpEntity entity = response.getEntity();
if (entity != null) {
//获取请求头，根据请求头进行不同的处理
String contentType = entity.getContentType().getValue();
web = EntityUtils.toString(entity,"utf-8");
httpClientContext.getCookieStore().getCookies().forEach(System.out::println);
}
response.close();
httpclient.close();
}catch (Exception e) {
e.printStackTrace();
} finally {
//关闭连接,释放资源
try {
response.close();
httpclient.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return web;
}
/*
* get请求参数封装，手写
*/
private static String setDoGetUrl(String url, Map<String,Object> map) {
if(StringUtils.isBlank(url))return url;
if(MapUtils.isEmpty(map))return url;
if(!url.endsWith("?")) url += "?";
for (Map.Entry<String,Object> entry:map.entrySet()) {
if(StringUtils.isBlank(entry.getKey()))continue;
if(!url.endsWith("?")){
url += "&" + entry.getKey() + "=" + entry.getValue().toString();
}else{
url += entry.getKey() + "=" + entry.getValue().toString();
}
}
return url;
}
3.2 restTemplate的get请求
restTemplate并没有重写底层的HTTP请求技术，而是提供配置，可选用OkHttp/HttpClient等，说白了就这对这两个封装。
这个就很简单了，
