zoukankan      html  css  js  c++  java

  • Apache HttpClient4使用教程

    基于HttpClient 4.5.2

    1. 执行GET请求

      CloseableHttpClient httpClient = HttpClients.custom()
                .build();
CloseableHttpResponse response = httpClient.execute(new HttpGet("https://www.baidu.com"));
System.out.println(EntityUtils.toString(response.getEntity()));

    2. 执行POST请求

      1. 提交form表单参数
        CloseableHttpClient httpClient = HttpClients.custom()
        .build();
HttpPost httpPost = new HttpPost("https://www.explame.com");
List<NameValuePair> formParams = new ArrayList<NameValuePair>();
//表单参数
formParams.add(new BasicNameValuePair("name1", "value1"));
formParams.add(new BasicNameValuePair("name2", "value2"));
UrlEncodedFormEntity entity = new UrlEncodedFormEntity(formParams, "utf-8");
httpPost.setEntity(entity);
CloseableHttpResponse response = httpClient.execute(httpPost);
System.out.println(EntityUtils.toString(response.getEntity()));
      2. 提交payload参数
        CloseableHttpClient httpClient = HttpClients.custom()
            .build();
HttpPost httpPost = new HttpPost("https://www.explame.com");
StringEntity entity = new StringEntity("{"id": "1"}");
httpPost.setEntity(entity);
CloseableHttpResponse response = httpClient.execute(httpPost);
System.out.println(EntityUtils.toString(response.getEntity()));
      3. post上传文件
        CloseableHttpClient httpClient = HttpClients.custom()
        .build();
HttpPost httpPost = new HttpPost("https://www.example.com");
MultipartEntityBuilder multipartEntityBuilder = MultipartEntityBuilder.create();
//要上传的文件
multipartEntityBuilder.addBinaryBody("file", new File("temp.txt"));
httpPost.setEntity(multipartEntityBuilder.build());
CloseableHttpResponse response = httpClient.execute(httpPost);
System.out.println(EntityUtils.toString(response.getEntity()));
      4. post提交multipart/form-data类型参数
        CloseableHttpClient httpClient = HttpClients.custom()
        .build();
HttpPost httpPost = new HttpPost("https://www.example.com");
MultipartEntityBuilder multipartEntityBuilder = MultipartEntityBuilder.create();
multipartEntityBuilder.addTextBody("username","wycm");
multipartEntityBuilder.addTextBody("passowrd","123");
//文件
multipartEntityBuilder.addBinaryBody("file", new File("temp.txt"));
httpPost.setEntity(multipartEntityBuilder.build());
CloseableHttpResponse response = httpClient.execute(httpPost);
System.out.println(EntityUtils.toString(response.getEntity()));

    3. 设置User-Agent

          CloseableHttpClient httpClient = HttpClients.custom()
            .setUserAgent("Mozilla/5.0")
            .build();
    CloseableHttpResponse response = httpClient.execute(new HttpGet("https://www.baidu.com"));
    System.out.println(EntityUtils.toString(response.getEntity()));

    4. 设置重试处理器
      当请求超时, 会自动重试，最多3次

      HttpRequestRetryHandler retryHandler = (exception, executionCount, context) -> {
    if (executionCount >= 3) {
        return false;
    }
    if (exception instanceof InterruptedIOException) {
        return true;
    }
    if (exception instanceof UnknownHostException) {
        return true;
    }
    if (exception instanceof ConnectTimeoutException) {
        return true;
    }
    if (exception instanceof SSLException) {
        return true;
    }
    HttpClientContext clientContext = HttpClientContext.adapt(context);
    HttpRequest request = clientContext.getRequest();
    boolean idempotent = !(request instanceof HttpEntityEnclosingRequest);
    if (idempotent) {
        return true;
    }
    return false;
};
CloseableHttpClient httpClient = HttpClients.custom()
        .setRetryHandler(retryHandler)
        .build();
httpClient.execute(new HttpGet("https://www.baidu.com"));

    5. 重定向策略

      1. HttpClient默认情况
        会对302、307的GET和HEAD请求以及所有的303状态码做重定向处理
      2. 关闭自动重定向
        CloseableHttpClient httpClient = HttpClients.custom()
         //关闭httpclient重定向
        .disableRedirectHandling()
        .build();
      3. POST支持302状态码重定向
        CloseableHttpClient httpClient = HttpClients.custom()
    //post 302支持重定向
    .setRedirectStrategy(new LaxRedirectStrategy())
    .build();
CloseableHttpResponse response = httpClient.execute(new HttpPost("https://www.explame.com"));
System.out.println(EntityUtils.toString(response.getEntity()));

    6. 定制cookie

      • 方式一：通过addHeader方式设置（不推荐这种方式）
            CloseableHttpClient httpClient = HttpClients.custom()
            .build();
    HttpGet httpGet = new HttpGet("http://www.example.com");
    httpGet.addHeader("Cookie", "name=value");
    httpClient.execute(httpGet);
        由于HttpClient默认会维护cookie状态。如果这个请求response中有Set-Cookie头，那下次请求的时候httpclient默认会把这个Cookie带上。并且会新建一行header。如果再遇到
        httpGet.addHeader("Cookie", "name=value");
        那么下次请求则会有两行name为Cookie的header。
      • 方式二：通过CookieStore的方式，以浏览器中的cookie为例（推荐）
        //此处直接粘贴浏览器cookie
final String RAW_COOKIES = "name1=value1; name2=value2";
final CookieStore cookieStore = new BasicCookieStore();
for (String rawCookie : RAW_COOKIES.split("; ")){
    String[] s = rawCookie.split("=");
    BasicClientCookie cookie = new BasicClientCookie(s[0], s[1]);
    cookie.setDomain("baidu.com");
    cookie.setPath("/");
    cookie.setSecure(false);
    cookie.setAttribute("domain", "baidu.com");
    Calendar calendar = Calendar.getInstance();
    calendar.add(Calendar.DAY_OF_MONTH, +5);
    cookie.setExpiryDate(calendar.getTime());
    cookieStore.addCookie(cookie);
}
CloseableHttpClient httpClient = HttpClients.custom()
        .setDefaultCookieStore(cookieStore)
        .build();
httpClient.execute(new HttpGet("https://www.baidu.com"));
        这种方式把定制的cookie交给httpclient维护。

    7. cookie管理

      • 方式一：初始化HttpClient时，传入一个自己CookieStore对象
        CookieStore cookieStore = new BasicCookieStore();
CloseableHttpClient httpClient = HttpClients.custom()
        .setDefaultCookieStore(cookieStore)
        .build();
httpClient.execute(new HttpGet("https://www.baidu.com"));
//请求一次后,清理cookie再发起一次新的请求
cookieStore.clear();
httpClient.execute(new HttpGet("https://www.baidu.com"));
      • 方式二：每次执行请求的时候传入自己的HttpContext对象
        //注:HttpClientContext不是线程安全的，不要多个线程维护一个HttpClientContext
HttpClientContext httpContext = HttpClientContext.create();
CloseableHttpClient httpClient = HttpClients.custom()
        .build();
httpClient.execute(new HttpGet("https://www.baidu.com"), httpContext);
//请求一次后,清理cookie再发起一次新的请求
httpContext.getCookieStore().clear();
httpClient.execute(new HttpGet("https://www.baidu.com"));

    8. http代理的配置

      CloseableHttpClient httpClient = HttpClients.custom()
        //设置代理
        .setRoutePlanner(new DefaultProxyRoutePlanner(new HttpHost("localhost", 8888)))
        .build();
CloseableHttpResponse response = httpClient.execute(new HttpGet("http://www.example.com"));
System.out.println(EntityUtils.toString(response.getEntity()));

    9. SSL配置

      //默认信任
SSLContext sslContext = SSLContexts.custom()
        .loadTrustMaterial(KeyStore.getInstance(KeyStore.getDefaultType())
                , (chain, authType) -> true).build();
Registry<ConnectionSocketFactory> socketFactoryRegistry =
        RegistryBuilder.<ConnectionSocketFactory>create()
                .register("http", new SocketProxyPlainConnectionSocketFactory())
                .register("https", new SocketProxySSLConnectionSocketFactory(sslContext))
                .build();
CloseableHttpClient httpClient = HttpClients.custom()
        .setConnectionManager(new PoolingHttpClientConnectionManager(socketFactoryRegistry))
        .build();
HttpClientContext httpClientContext = HttpClientContext.create();
httpClientContext.setAttribute("socks.address", new InetSocketAddress("127.0.0.1", 1086));
CloseableHttpResponse response = httpClient.execute(new HttpGet("https://httpbin.org/ip"), httpClientContext);
System.out.println(EntityUtils.toString(response.getEntity()));

    10. socket代理配置

      static class SocketProxyPlainConnectionSocketFactory extends PlainConnectionSocketFactory{
    @Override
    public Socket createSocket(final HttpContext context) {
        InetSocketAddress socksAddr = (InetSocketAddress) context.getAttribute("socks.address");
        if (socksAddr != null){
            Proxy proxy = new Proxy(Proxy.Type.SOCKS, socksAddr);
            return new Socket(proxy);
        } else {
            return new Socket();
        }
    }
}
static class SocketProxySSLConnectionSocketFactory extends SSLConnectionSocketFactory {
    public SocketProxySSLConnectionSocketFactory(final SSLContext sslContext) {
        super(sslContext, NoopHostnameVerifier.INSTANCE);
    }

    @Override
    public Socket createSocket(final HttpContext context) {
        InetSocketAddress socksAddr = (InetSocketAddress) context.getAttribute("socks.address");
        if (socksAddr != null){
            Proxy proxy = new Proxy(Proxy.Type.SOCKS, socksAddr);
            return new Socket(proxy);
        } else {
            return new Socket();
        }
    }

}
/**
 * socket代理配置
 */
public static void socketProxy() throws Exception {
    //默认信任
    SSLContext sslContext = SSLContexts.custom()
            .loadTrustMaterial(KeyStore.getInstance(KeyStore.getDefaultType())
                    , (X509Certificate[] chain, String authType) -> true).build();
    Registry<ConnectionSocketFactory> socketFactoryRegistry =
            RegistryBuilder.<ConnectionSocketFactory>create()
                    .register("http", new SocketProxyPlainConnectionSocketFactory())
                    .register("https", new SocketProxySSLConnectionSocketFactory(sslContext))
                    .build();
    CloseableHttpClient httpClient = HttpClients.custom()
            .setConnectionManager(new PoolingHttpClientConnectionManager(socketFactoryRegistry))
            .build();
    HttpClientContext httpClientContext = HttpClientContext.create();
    httpClientContext.setAttribute("socks.address", new InetSocketAddress("127.0.0.1", 1086));
    CloseableHttpResponse response = httpClient.execute(new HttpGet("https://httpbin.org/ip"), httpClientContext);
    System.out.println(EntityUtils.toString(response.getEntity()));
}

    11. 下载文件

      CloseableHttpClient httpClient = HttpClients.custom().build();
CloseableHttpResponse response = httpClient.execute(new HttpGet("https://www.example.com"));
InputStream is = response.getEntity().getContent();
Files.copy(is, new File("temp.png").toPath(), StandardCopyOption.REPLACE_EXISTING);

    最后

    版权声明
    作者：wycm
    出处：https://www.cnblogs.com/w-y-c-m/p/9237335.html
    您的支持是对博主最大的鼓励，感谢您的认真阅读。
    本文版权归作者所有，欢迎转载，但未经作者同意必须保留此段声明，且在文章页面明显位置给出原文连接，否则保留追究法律责任的权利。
    一个程序员日常分享，包括但不限于爬虫、Java后端技术，欢迎关注
  • 相关阅读:
    StringUtils
    改变windows锁屏时间
    data-toggle和data-target
    Bootstrap元素居中
    爬虫软件/程序
    nfs服务器搭建
    浏览器控制台console对象的使用
    F7
    Ubuntu18.04 安装Docker【转】
    mysql出现ERROR1698(28000):Access denied for user root@localhost错误解决方法【转】
  • 原文地址：https://www.cnblogs.com/w-y-c-m/p/9237335.html
Copyright © 2011-2022 走看看