httpClient - 编程耽误的厨子

httpClient

一、httpClient简介

　　官网：http://hc.apache.org/

　　使用场景：

　　　　爬虫

　　　　多系统之间接口交互

二、使用HttpClient获取网页内容

-导入依赖

<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.13</version>
</dependency>

public class HttpURLConnTest {
    /**
     *   使用jdk原生的api来请求网页
     */

    @Test
    public void  test() throws Exception {
        // 打开浏览器
        CloseableHttpClient httpClient = HttpClientBuilder.create().build();
        // 输入url地址
        HttpGet httpGet = new HttpGet("https://www.baidu.com/");
        CloseableHttpResponse response = null;
        try {
            // 敲回车，发送请求，获取响应
            response = httpClient.execute(httpGet);
            // 获取内容
            String result = EntityUtils.toString(response.getEntity(), "utf-8");
            System.out.println(result);
        } catch (IOException e) {
            e.printStackTrace();
        }finally {
            try {
                if (response != null) {
                    response.close();
                }
                if (httpGet != null) {
                    httpGet.releaseConnection();
                }
                if (httpClient != null) {
                    httpClient.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }

        }
    }

}

-可以看到运行的结果是百度的源代码

<!DOCTYPE html>
<!--STATUS OK--><html> <head><meta http-equiv=content-type content=text/html;charset=utf-8><meta http-equiv=X-UA-Compatible content=IE=Edge><meta content=always name=referrer><link rel=stylesheet type=text/css href=https://ss1.bdstatic.com/5eN1bjq8AAUYm2zgoY3K/r/www/cache/bdorz/baidu.min.css><title>百度一下，你就知道</title></head> <body link=#0000cc> <div id=wrapper> <div id=head> <div class=head_wrapper> <div class=s_form> <div class=s_form_wrapper> <div id=lg> <img hidefocus=true src=//www.baidu.com/img/bd_logo1.png width=270 height=129> </div> <form id=form name=f action=//www.baidu.com/s class=fm> <input type=hidden name=bdorz_come value=1> <input type=hidden name=ie value=utf-8> <input type=hidden name=f value=8> <input type=hidden name=rsv_bp value=1> <input type=hidden name=rsv_idx value=1> <input type=hidden name=tn value=baidu><span class="bg s_ipt_wr"><input id=kw name=wd class=s_ipt value maxlength=255 autocomplete=off autofocus=autofocus></span><span class="bg s_btn_wr"><input type=submit id=su value=百度一下 class="bg s_btn" autofocus></span> </form> </div> </div> <div id=u1> <a href=http://news.baidu.com name=tj_trnews class=mnav>新闻</a> <a href=https://www.hao123.com name=tj_trhao123 class=mnav>hao123</a> <a href=http://map.baidu.com name=tj_trmap class=mnav>地图</a> <a href=http://v.baidu.com name=tj_trvideo class=mnav>视频</a> <a href=http://tieba.baidu.com name=tj_trtieba class=mnav>贴吧</a> <noscript> <a href=http://www.baidu.com/bdorz/login.gif?login&amp;tpl=mn&amp;u=http%3A%2F%2Fwww.baidu.com%2f%3fbdorz_come%3d1 name=tj_login class=lb>登录</a> </noscript> <script>document.write('<a href="http://www.baidu.com/bdorz/login.gif?login&tpl=mn&u='+ encodeURIComponent(window.location.href+ (window.location.search === "" ? "?" : "&")+ "bdorz_come=1")+ '" name="tj_login" class="lb">登录</a>');
                </script> <a href=//www.baidu.com/more/ name=tj_briicon class=bri style="display: block;">更多产品</a> </div> </div> </div> <div id=ftCon> <div id=ftConw> <p id=lh> <a href=http://home.baidu.com>关于百度</a> <a href=http://ir.baidu.com>About Baidu</a> </p> <p id=cp>&copy;2017&nbsp;Baidu&nbsp;<a href=http://www.baidu.com/duty/>使用百度前必读</a>&nbsp; <a href=http://jianyi.baidu.com/ class=cp-feedback>意见反馈</a>&nbsp;京ICP证030173号&nbsp; <img src=//www.baidu.com/img/gs.gif> </p> </div> </div> </div> </body> </html>

三、发送Get无参请求

public class HttpClientTest {
    /**
     * 使用HttpClient发送Get请求
     */
    @Test
    public void testGet() {
        CloseableHttpClient aDefault = HttpClients.createDefault();
        // 输入url地址
        //构造httpGet请求对象
        HttpGet httpGet = new HttpGet("https://www.baidu.com/");
        //可关闭的响应
        CloseableHttpResponse response = null;
        try {
            response = aDefault.execute(httpGet);
            //获取响应结果：DecompressingEntity
            HttpEntity entity = response.getEntity();
            //对HttpEntity进行操作
            String s = EntityUtils.toString(entity, StandardCharsets.UTF_8);
            System.out.println(s);
            //确保流关闭
            EntityUtils.consume(entity);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (aDefault != null) {
                try {
                    aDefault.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (response != null) {
                try {
                    response.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

    }
}

运行结果同上

-保存网络图片到本地

public  void  test2() throws  Exception{
        CloseableHttpClient closeableHttpClient = HttpClients.createDefault();
        String urlStr="https://pics5.baidu.com/feed/c9fcc3cec3fdfc03f254ca734915349ea5c22685.png?token=3c875fd7c636738571cee9df4199e80c";
        HttpGet httpGet=new HttpGet(urlStr);
        //可关闭的响应
        CloseableHttpResponse response=null;
        try {
            response=closeableHttpClient.execute(httpGet);
            HttpEntity entity = response.getEntity();
            //image/jpg  image/jpeg  image/png  image  图片的后缀

            String contentType = entity.getContentType().getValue();
            String suffix=".jpg";
            if (contentType.contains("jpg")||contentType.contains("jpeg")){
                suffix=".jpg";
            } else if (contentType.contains("bmp")||contentType.contains("bitmap")) {
                suffix=".bmp";
            } else if (contentType.contains("png")) {
                suffix=".png";
            }
            else if (contentType.contains("gif")) {
                suffix=".gif";
            }
            //获取文件的字节流
            byte[] bytes = EntityUtils.toByteArray(entity);
            String localAbsPath="E:\\CloudMusic\\abc"+suffix;
            FileOutputStream fos=new FileOutputStream(localAbsPath);
                    fos.write(bytes);
                    fos.close();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (closeableHttpClient != null) {
                try {
                    closeableHttpClient.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (response != null) {
                try {
                    response.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

-设置访问代理

/**
     * 设置访问代理
     */
    @Test
    public  void  test3() throws Exception{
        CloseableHttpClient closeableHttpClient = HttpClients.createDefault();
        String urlStr="https://www.baidu.com/";
        HttpGet httpGet=new HttpGet(urlStr);
        //创建一个代理
        String ip="195.53.49.11";
        int port=3128;
          HttpHost proxy= new HttpHost(ip,port);
        //对每一个请求进行配置，会覆盖全局默认请求配置
        RequestConfig requestConfig = RequestConfig.custom().setProxy(proxy).build();
        httpGet.setConfig(requestConfig);
        CloseableHttpResponse response=null;
        try {
            response=closeableHttpClient.execute(httpGet);
            HttpEntity entity = response.getEntity();
            String toStringResult = EntityUtils.toString(entity);
            EntityUtils.consume(entity);
        }catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (closeableHttpClient != null) {
                try {
                    closeableHttpClient.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (response != null) {
                try {
                    response.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

-设置连接超时时间

 /**
     * 设置链接超时时间
     *
     */
    @Test
    public  void  test4() throws Exception{
        CloseableHttpClient closeableHttpClient = HttpClients.createDefault();
        String urlStr="https://www.github.com//";
        HttpGet httpGet=new HttpGet(urlStr);
        //创建一个代理
        String ip="195.53.49.11";
        int port=3128;
        HttpHost proxy= new HttpHost(ip,port);
        //对每一个请求进行配置，会覆盖全局默认请求配置
        RequestConfig requestConfig = RequestConfig
                .custom()
                //超时时间,ms为单位 完成tcp3次握手 的时间上限
                .setConnectTimeout(5000)
                //读取超时，ms为单位，表示从请求的网址处获得响应数据的时间间隔
                .setSocketTimeout(3000)
                //从连接池里获取connection的超时时间
                .setConnectionRequestTimeout(5000)
                .build();
        httpGet.setConfig(requestConfig);
        CloseableHttpResponse response=null;
        try {
            response=closeableHttpClient.execute(httpGet);
            HttpEntity entity = response.getEntity();
            String toStringResult = EntityUtils.toString(entity);
            EntityUtils.consume(entity);
        }catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (closeableHttpClient != null) {
                try {
                    closeableHttpClient.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (response != null) {
                try {
                    response.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

四、发送Get带参数请求

 /**
     * httpGet有参请求
     *
     * @throws Exception
     */
    @Test
    public void HttpClientParamTest() throws Exception {
        //创建HttpClients对象
        CloseableHttpClient closeableHttpClient = HttpClients.createDefault();
        //设置请求地址
        //创建urlBuilder
        URIBuilder uriBuilder=new URIBuilder("http://yun.itheima.com/search");
        //设置参数
        uriBuilder.setParameter("keys","Java");
        //HttpGet对象 设置url访问地址
        HttpGet httpGet = new HttpGet(uriBuilder.build());
        System.out.println("发送请求信息"+httpGet);
        CloseableHttpResponse response = null;
        try {
            response = closeableHttpClient.execute(httpGet);
            //解析响应
            if (response.getStatusLine().getStatusCode() == 200) {
                String content = EntityUtils.toString(response.getEntity(), "utf-8");
                System.out.println(content.length());
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (closeableHttpClient != null) {
                try {
                    closeableHttpClient.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (response != null) {
                try {
                    response.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

五、post无参数请求

  /**
     * httpPost 无参数请
     *
     * @throws Exception
     */
    @Test
    public void HttpClientPostTest() throws Exception {
        //创建HttpClients对象
        CloseableHttpClient closeableHttpClient = HttpClients.createDefault();

        //HttpPost对象 设置url访问地址
        HttpPost httpPost = new HttpPost();

        CloseableHttpResponse response = null;
        try {
            response = closeableHttpClient.execute(httpPost);
            //解析响应
            if (response.getStatusLine().getStatusCode() == 200) {
                String content = EntityUtils.toString(response.getEntity(), "utf-8");
                System.out.println(content.length());
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (closeableHttpClient != null) {
                try {
                    closeableHttpClient.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (response != null) {
                try {
                    response.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

六、post有参请求

 /**
     * httpPost 带参数请求
     *
     * @throws Exception
     */
    @Test
    public void HttpClientPostParamTest() throws Exception {
        //创建HttpClients对象
        CloseableHttpClient closeableHttpClient = HttpClients.createDefault();
        //HttpPost对象 设置url访问地址
        HttpPost httpPost = new HttpPost("http://yun.itheima.com/search");
        //声明list集合，封装表单中的参数
        List<NameValuePair> params = new ArrayList<NameValuePair>();
        //设置请求地址：http：//yun.itheima.com/search?keys=Java
        params.add(new BasicNameValuePair("keys", "java"));
        //创建表单的Entity对象
        UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(params, "utf-8");
        //设置表单的Entity对象到post请求中
        httpPost.setEntity(formEntity);
        CloseableHttpResponse response = null;
        try {
            response = closeableHttpClient.execute(httpPost);
            //解析响应
            if (response.getStatusLine().getStatusCode() == 200) {
                String content = EntityUtils.toString(response.getEntity(), "utf-8");
                System.out.println(content.length());
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (closeableHttpClient != null) {
                try {
                    closeableHttpClient.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (response != null) {
                try {
                    response.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

七、连接池

-若每次请求都要创建HttpClient会有频繁创建和销毁问题，可以使用连接池来解决

/**
     * 连接池管理HttpClient
     *
     * @throws Exception
     */
    @Test
    public void HttpClientPoolTest() {
        //创建连接池管理器
        PoolingHttpClientConnectionManager cm = new PoolingHttpClientConnectionManager();
        //设置最大链接数
        cm.setMaxTotal(100);

        //设置每个主机最大连接数
        cm.setDefaultMaxPerRoute(10);

        //使用连接池管理器发送请求
        doGet(cm);
        doGet(cm);

    }

    private void doGet(PoolingHttpClientConnectionManager cm) {
        //不会每次创建新的HttpClient，而是从连接池中获取HttpClient对象
        CloseableHttpClient httpClient = HttpClients.custom().setConnectionManager(cm).build();
        HttpGet httpGet = new HttpGet("http://www.itcast.cn");
        CloseableHttpResponse response = null;
        try {
            response = httpClient.execute(httpGet);
            if (response.getStatusLine().getStatusCode() == 200) {
                String content = EntityUtils.toString(response.getEntity());
                System.out.println(content.length());
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (response != null) {
                try {
                    response.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
                //不能关闭HttpClient
                // httpClient.close();
            }
        }

    }

八、HttpClient请求参数

/**
     * HttpClient 请求参数
     */
    @Test
    public void HttpClientConfigTest()  {
        //创建HttpClients对象
        CloseableHttpClient closeableHttpClient = HttpClients.createDefault();

        //HttpPost对象 设置url访问地址
        HttpGet httpGet = new HttpGet("http://www.itcast.cn");
        //配置请求信息
        RequestConfig config=RequestConfig
                .custom()
                .setConnectionRequestTimeout(1000)  //创建链接的最长时间，单位是毫秒
                .setConnectionRequestTimeout(500)   //设置获取链接最长时间
                .setSocketTimeout(10*1000)          //设置数据传输的最长时间
                .build();
        //设置请求信息
        httpGet.setConfig(config);
        CloseableHttpResponse response = null;
        try {
            response = closeableHttpClient.execute(httpGet);
            //解析响应
            if (response.getStatusLine().getStatusCode() == 200) {
                String content = EntityUtils.toString(response.getEntity(), "utf-8");
                System.out.println(content.length());
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (closeableHttpClient != null) {
                try {
                    closeableHttpClient.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (response != null) {
                try {
                    response.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

posted on 2022-07-27 13:46 编程耽误的厨子阅读(234) 评论(0) 收藏举报

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