HttpClient详解及如何设置忽略SSL

一、简介HttpClient 是Apache Jakarta Common 下的子项目，可以用来提供高效的、最新的、功能丰富的支持 HTTP 协议的客户端编程工具包，并且它支持 HTTP 协议最新的版本和建议。HttpClient 是 Apache Jakarta Common 下的子项目，用来提供高效的、最新的、功能丰富的支持 HTTP 协议的客户端编程工具包，并且它支持 HTTP 协议...

Jeremy_Lee123

7274人浏览 · 2019-07-24 23:36:35

Jeremy_Lee123 · 2019-07-24 23:36:35 发布

一、简介

HttpClient 是Apache Jakarta Common 下的子项目，可以用来提供高效的、最新的、功能丰富的支持 HTTP 协议的客户端编程工具包，并且它支持 HTTP 协议最新的版本和建议。

HttpClient 是 Apache Jakarta Common 下的子项目，用来提供高效的、最新的、功能丰富的支持 HTTP 协议的客户端编程工具包，并且它支持 HTTP 协议最新的版本和建议。HttpClient 已经应用在很多的项目中，比如 Apache Jakarta 上很著名的另外两个开源项目 Cactus 和 HTMLUnit 都使用了 HttpClient。现在HttpClient最新版本为 HttpClient 4.5.x

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.6</version>
</dependency>

二、基本功能

实现了所有 HTTP 的方法（GET,POST,PUT,HEAD 等）
支持自动转向
支持 HTTPS 协议
支持代理服务器等

2.1 GET方法

    /** 
     * 发送 get请求 
     */   
    public void get() {   
        CloseableHttpClient httpclient = HttpClients.createDefault();   
        try {   
            // 创建httpget.     
            HttpGet httpget = new HttpGet("http://www.baidu.com/");   
            System.out.println("executing request " + httpget.getURI());   
            // 执行get请求.     
            CloseableHttpResponse response = httpclient.execute(httpget);   
            try {   
                // 获取响应实体     
                HttpEntity entity = response.getEntity();   
                System.out.println("--------------------------------------");   
                // 打印响应状态     
                System.out.println(response.getStatusLine());   
                if (entity != null) {   
                    // 打印响应内容长度     
                    System.out.println("Response content length: " + entity.getContentLength());   
                    // 打印响应内容     
                    System.out.println("Response content: " + EntityUtils.toString(entity));   
                }   
                System.out.println("------------------------------------");   
            } finally {   
                response.close();   
            }   
        } catch (ClientProtocolException e) {   
            e.printStackTrace();   
        } catch (ParseException e) {   
            e.printStackTrace();   
        } catch (IOException e) {   
            e.printStackTrace();   
        } finally {   
            // 关闭连接,释放资源     
            try {   
                httpclient.close();   
            } catch (IOException e) {   
                e.printStackTrace();   
            }   
        }   
    }

2.2 POST方法

    /** 
     * 发送 post请求访问本地应用并根据传递参数不同返回不同结果 
     */   
    public void post() {   
        // 创建默认的httpClient实例.     
        CloseableHttpClient httpclient = HttpClients.createDefault();   
        // 创建httppost     
        HttpPost httppost = new HttpPost("http://localhost:8080/myDemo/Ajax/serivceJ.action");   
        // 创建参数队列     
        List<NameValuePair> formparams = new ArrayList<NameValuePair>();   
        formparams.add(new BasicNameValuePair("type", "house"));   
        UrlEncodedFormEntity uefEntity;   
        try {   
            uefEntity = new UrlEncodedFormEntity(formparams, "UTF-8");   
            httppost.setEntity(uefEntity);   
            System.out.println("executing request " + httppost.getURI());   
            CloseableHttpResponse response = httpclient.execute(httppost);   
            try {   
                HttpEntity entity = response.getEntity();   
                if (entity != null) {   
                    System.out.println("--------------------------------------");   
                    System.out.println("Response content: " + ntityUtils.toString(entity, "UTF-8"));   
                    System.out.println("--------------------------------------");   
                }   
            } finally {   
                response.close();   
            }   
        } catch (ClientProtocolException e) {   
            e.printStackTrace();   
        } catch (UnsupportedEncodingException e1) {   
            e1.printStackTrace();   
        } catch (IOException e) {   
            e.printStackTrace();   
        } finally {   
            // 关闭连接,释放资源     
            try {   
                httpclient.close();   
            } catch (IOException e) {   
                e.printStackTrace();   
            }   
        }   
    }

参考资料：

https://www.kancloud.cn/longxuan/httpclient-arron/117499 https://blog.csdn.net/xiaoxian8023 https://blog.csdn.net/w372426096/article/details/82713315

三、常见问题之一：如何设置忽略SSL

有时我们需要访问一些采用Https安全协议的网站，我们可以定制SSL/TLS的方式来访问该网站，HttpClient是支持的。定制SSL/TLS下节记录。采用定制SSL/TLS的方式需要导出对应网站的证书，证书还有可能过期，需要重新导入，这时可以采用绕过证书的方式。当然，有的网站是Https但是浏览器还是显示不安全，就没办法导出证书，比如12306。

解决常见报错：

方式一：

HttpHost proxy = new HttpHost("10.31.16.216",18103);
CloseableHttpClient httpClient = HttpClients.custom()
        .setProxy(proxy)
        .setHostnameVerifier(new AllowAllHostnameVerifier())
        .setSslcontext(new SSLContextBuilder().loadTrustMaterial(null, new TrustStrategy()
            {
                public boolean isTrusted(X509Certificate[] arg0, String arg1) throws CertificateException
                {
                    return true;
                }
            }).build()).build();


 	HttpURLConnection configurator =new HttpURLConnection(null) {
		
		@Override
		public void connect() throws IOException {
			// TODO Auto-generated method stub
			
		}
		
		@Override
		public boolean usingProxy() {
			// TODO Auto-generated method stub
			return false;
		}
		
		@Override
		public void disconnect() {
			// TODO Auto-generated method stub
			
		}
	};

	@PostConstruct
	public void init() throws Exception{
	RequestConfig httpConfig=RequestConfig.custom()
			.setExpectContinueEnabled(false)
			.setConnectionRequestTimeout(Integer.valueOf("configurator.getTransportConfig().getConnectionTimeout()"))
			.setConnectTimeout(Integer.valueOf("configurator.getTransportConfig().getConnectionTimeout()"))
	        .setSocketTimeout(Integer.valueOf("configurator.getTransportConfig().getsocketTimeout()"))
	        .build();
	SSLContext sslContextIgnore=SSLContexts.custom().loadTrustMaterial((cert,para)->true).build();
	//SSLContext sslContextIgnore=SSLContexts.custom().build();
	SSLConnectionSocketFactory 	socketFactoryIgnore=new SSLConnectionSocketFactory(sslContextIgnore,NoopHostnameVerifier.INSTANCE);
	
	HttpClient httpClient=	HttpClients.custom()
			.setDefaultRequestConfig(httpConfig)
			.setMaxConnPerRoute(Integer.valueOf("configurator.getTransportConfig().getPoolMmaxSizePerRoute()"))
			.setSSLContext(sslContextIgnore)
			.setSSLSocketFactory(socketFactoryIgnore)
			.build();
	}
}

方式二：

  SSLContextBuilder builder = new SSLContextBuilder();
    builder.loadTrustMaterial(null, new TrustSelfSignedStrategy());
    SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(
            builder.build());
    CloseableHttpClient httpclient = HttpClients.custom().setSSLSocketFactory(
            sslsf).build();

    HttpGet httpGet = new HttpGet("https://www.baidu.com");
    CloseableHttpResponse response = httpclient.execute(httpGet);
    try {
        System.out.println(response.getStatusLine());
        HttpEntity entity = response.getEntity();
        EntityUtils.consume(entity);
    }
    finally {
        response.close();
    }

方式三：

SSLContextBuilder builder = SSLContexts.custom();
builder.loadTrustMaterial(null, new TrustStrategy() {
    @Override
    public boolean isTrusted(X509Certificate[] chain, String authType)
            throws CertificateException {
        return true;
    }
});
SSLContext sslContext = builder.build();
SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(
        sslContext, new X509HostnameVerifier() {
            @Override
            public void verify(String host, SSLSocket ssl)
                    throws IOException {
            }

            @Override
            public void verify(String host, X509Certificate cert)
                    throws SSLException {
            }

            @Override
            public void verify(String host, String[] cns,
                    String[] subjectAlts) throws SSLException {
            }

            @Override
            public boolean verify(String s, SSLSession sslSession) {
                return true;
            }
        });

Registry<ConnectionSocketFactory> socketFactoryRegistry = RegistryBuilder
        .<ConnectionSocketFactory> create().register("https", sslsf)
        .build();

PoolingHttpClientConnectionManager cm = new PoolingHttpClientConnectionManager(
        socketFactoryRegistry);
CloseableHttpClient httpclient = HttpClients.custom()
        .setConnectionManager(cm).build();

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