Java微型浏览器——HttpClient 4.5.6简要学习总结

版权声明：转载请注明出处哦 https://blog.csdn.net/k99sam/article/details/83819164

原料：

MAVEN导入

  <!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpclient -->
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.5.6</version>
        </dependency>

---

例1：Get网页并存盘

        CloseableHttpClient defaultHttpClient = HttpClients.createDefault();

        HttpGet hg = new HttpGet("http://www.k99sam.com/photos/list");

        //设置cookie
        hg.setHeader("cookie", "t=ea927b137ec52d665a842efa2e5eb5bc9; path=/; domain=.k99sam.com; Expires=Tue, 19 Jan 2038 03:14:07 GMT;");

        HttpResponse httpResponse = defaultHttpClient.execute(hg);

        File f1 = new File("temp.html");

        InputStream is =  httpResponse.getEntity().getContent();

        //这里用EntityUtils获得原始网页代码文本，HTTP.UTF_8已过时了，用StandardCharsets.UTF_8替代！
        String srcHtml = EntityUtils.toString(httpResponse.getEntity(), StandardCharsets.UTF_8);

        FileOutputStream fos = new FileOutputStream(f1);

        fos.write(srcHtml.getBytes());

        fos.close();

---

例2：Get图片或文件资源

        CloseableHttpClient defaultHttpClient = HttpClients.createDefault();

        HttpGet hg = new HttpGet("http://www.k99sam.com/photos/yourwife.jpg");

        hg.setHeader("cookie","t=ea927b137ec52d665a842efa2e5eb5bc9; path=/; domain=.k99sam.com; Expires=Tue, 19 Jan 2038 03:14:07 GMT;");

        HttpResponse httpResponse = defaultHttpClient.execute(hg);

        File f1 = new File("test.jpg");

        InputStream is =  httpResponse.getEntity().getContent();

        FileOutputStream fos = new FileOutputStream(f1);

        byte[] buf = new byte[1024 * 1024];

        int size;

        while ((size = is.read(buf)) != -1){
            fos.write(buf,0,size);
        }

        fos.close();

        is.close();

        hg.releaseConnection();

---

例3：发送Post请求

        CloseableHttpClient defaultHttpClient = HttpClients.createDefault();
          
        //用BasicNameValuePair制作参数
        List<BasicNameValuePair> paramList = new ArrayList<>();

        paramList.add(new BasicNameValuePair("username","k99sam"));
        paramList.add(new BasicNameValuePair("password","123456"));

        HttpPost hp = new HttpPost("http://www.k99sam.com/addUser");

        //参数实体，注意编码！
        UrlEncodedFormEntity urlEncodedFormEntity = new UrlEncodedFormEntity(paramList,StandardCharsets.UTF_8);

        hp.setHeader("cookie","t=ea927b137ec52d665a842efa2e5eb5bc9; path=/; domain=.k99sam.com; Expires=Tue, 19 Jan 2038 03:14:07 GMT;");

        //设置body的实体
        hp.setEntity(urlEncodedFormEntity);

        HttpResponse httpResponse = defaultHttpClient.execute(hp);

        if (httpResponse.getStatusLine().getStatusCode() == 200){
            //do something....
        }
        hp.releaseConnection();