java中的http请求的封装（GET、POST、form表单形式）-白红宇

java中的http请求的封装（GET、POST、form表单形式）

阅读量：5812 次

发布时间：2019-06-18

本文共 22893 字，大约阅读时间需要 76 分钟。

目前JAVA实现HTTP请求的方法用的最多的有两种：一种是通过HTTPClient这种第三方的开源框架去实现。HTTPClient对HTTP的封装性比较不错，通过它基本上能够满足我们大部分的需求，HttpClient3.1 是 org.apache.commons.httpclient下操作远程 url的工具包，虽然已不再更新，但实现工作中使用httpClient3.1的代码还是很多，HttpClient4.5是org.apache.http.client下操作远程 url的工具包，最新的；另一种则是通过HttpURLConnection去实现，HttpURLConnection是JAVA的标准类，是JAVA比较原生的一种实现方式。

第一种方式：java原生HttpURLConnection

package com.mobile.utils;import com.alibaba.fastjson.JSONObject;import org.apache.log4j.Logger;import java.io.*;import java.net.HttpURLConnection;import java.net.MalformedURLException;import java.net.URL;import java.util.*;public class HttpUtil {    static Logger log = Logger.getLogger(HttpUtil.class);    /**     * 向指定URL发送GET方法的请求     *     * @param httpurl     *            请求参数用?拼接在url后边，请求参数应该是 name1=value1&name2=value2 的形式。     * @return result 所代表远程资源的响应结果     */    public static String doGet(String httpurl) {        HttpURLConnection connection = null;        InputStream is = null;        BufferedReader br = null;        String result = null;// 返回结果字符串        try {            // 创建远程url连接对象            URL url = new URL(httpurl);            // 通过远程url连接对象打开一个连接，强转成httpURLConnection类            connection = (HttpURLConnection) url.openConnection();            // 设置连接方式：get            connection.setRequestMethod("GET");            // 设置连接主机服务器的超时时间：15000毫秒            connection.setConnectTimeout(15000);            // 设置读取远程返回的数据时间：60000毫秒            connection.setReadTimeout(60000);            // 发送请求            connection.connect();            // 通过connection连接，获取输入流            if (connection.getResponseCode() == 200) {                is = connection.getInputStream();                // 封装输入流is，并指定字符集                br = new BufferedReader(new InputStreamReader(is, "UTF-8"));                // 存放数据                StringBuffer sbf = new StringBuffer();                String temp = null;                while ((temp = br.readLine()) != null) {                    sbf.append(temp);                    sbf.append("\r\n");                }                result = sbf.toString();            }        } catch (MalformedURLException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        } finally {            // 关闭资源            if (null != br) {                try {                    br.close();                } catch (IOException e) {                    e.printStackTrace();                }            }            if (null != is) {                try {                    is.close();                } catch (IOException e) {                    e.printStackTrace();                }            }            connection.disconnect();// 关闭远程连接        }        return result;    }    /**     * 向指定 URL 发送POST方法的请求     *     * @param httpUrl     *            发送请求的 URL     * @param param     *            请求参数应该是{"key":"==g43sEvsUcbcunFv3mHkIzlHO4iiUIT R7WwXuSVKTK0yugJnZSlr6qNbxsL8OqCUAFyCDCoRKQ882m6cTTi0q9uCJsq JJvxS+8mZVRP/7lWfEVt8/N9mKplUA68SWJEPSXyz4MDeFam766KEyvqZ99d"}的形式。     * @return 所代表远程资源的响应结果     */    public static String doPost(String httpUrl, String param) {        HttpURLConnection connection = null;        InputStream is = null;        OutputStream os = null;        BufferedReader br = null;        String result = null;        try {            URL url = new URL(httpUrl);            // 通过远程url连接对象打开连接            connection = (HttpURLConnection) url.openConnection();            // 设置连接请求方式            connection.setRequestMethod("POST");            // 设置连接主机服务器超时时间：15000毫秒            connection.setConnectTimeout(15000);            // 设置读取主机服务器返回数据超时时间：60000毫秒            connection.setReadTimeout(60000);            // 默认值为：false，当向远程服务器传送数据/写数据时，需要设置为true            connection.setDoOutput(true);            // 默认值为：true，当前向远程服务读取数据时，设置为true，该参数可有可无            connection.setDoInput(true);            // 设置传入参数的格式:请求参数应该是 name1=value1&name2=value2 的形式。            connection.setRequestProperty("Content-Type", "application/json");            // 设置鉴权信息：Authorization: Bearer da3efcbf-0845-4fe3-8aba-ee040be542c0            //connection.setRequestProperty("Authorization", "Bearer da3efcbf-0845-4fe3-8aba-ee040be542c0");            // 通过连接对象获取一个输出流            os = connection.getOutputStream();            // 通过输出流对象将参数写出去/传输出去,它是通过字节数组写出的            os.write(param.getBytes());            // 通过连接对象获取一个输入流，向远程读取            if (connection.getResponseCode() == 200) {                is = connection.getInputStream();                // 对输入流对象进行包装:charset根据工作项目组的要求来设置                br = new BufferedReader(new InputStreamReader(is, "UTF-8"));                StringBuffer sbf = new StringBuffer();                String temp = null;                // 循环遍历一行一行读取数据                while ((temp = br.readLine()) != null) {                    sbf.append(temp);                    sbf.append("\r\n");                }                result = sbf.toString();            }        } catch (MalformedURLException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        } finally {            // 关闭资源            if (null != br) {                try {                    br.close();                } catch (IOException e) {                    e.printStackTrace();                }            }            if (null != os) {                try {                    os.close();                } catch (IOException e) {                    e.printStackTrace();                }            }            if (null != is) {                try {                    is.close();                } catch (IOException e) {                    e.printStackTrace();                }            }            // 断开与远程地址url的连接            connection.disconnect();        }        return result;    }    /**     *     * @param httpUrl  请求的url     * @param param  form表单的参数（key,value形式）     * @return     */    public static String doPostForm(String httpUrl, Map param) {        HttpURLConnection connection = null;        InputStream is = null;        OutputStream os = null;        BufferedReader br = null;        String result = null;        try {            URL url = new URL(httpUrl);            // 通过远程url连接对象打开连接            connection = (HttpURLConnection) url.openConnection();            // 设置连接请求方式            connection.setRequestMethod("POST");            // 设置连接主机服务器超时时间：15000毫秒            connection.setConnectTimeout(15000);            // 设置读取主机服务器返回数据超时时间：60000毫秒            connection.setReadTimeout(60000);            // 默认值为：false，当向远程服务器传送数据/写数据时，需要设置为true            connection.setDoOutput(true);            // 默认值为：true，当前向远程服务读取数据时，设置为true，该参数可有可无            connection.setDoInput(true);            // 设置传入参数的格式:请求参数应该是 name1=value1&name2=value2 的形式。            connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");            // 设置鉴权信息：Authorization: Bearer da3efcbf-0845-4fe3-8aba-ee040be542c0            //connection.setRequestProperty("Authorization", "Bearer da3efcbf-0845-4fe3-8aba-ee040be542c0");            // 通过连接对象获取一个输出流            os = connection.getOutputStream();            // 通过输出流对象将参数写出去/传输出去,它是通过字节数组写出的(form表单形式的参数实质也是key,value值的拼接，类似于get请求参数的拼接)            os.write(createLinkString(param).getBytes());            // 通过连接对象获取一个输入流，向远程读取            if (connection.getResponseCode() == 200) {                is = connection.getInputStream();                // 对输入流对象进行包装:charset根据工作项目组的要求来设置                br = new BufferedReader(new InputStreamReader(is, "UTF-8"));                StringBuffer sbf = new StringBuffer();                String temp = null;                // 循环遍历一行一行读取数据                while ((temp = br.readLine()) != null) {                    sbf.append(temp);                    sbf.append("\r\n");                }                result = sbf.toString();            }        } catch (MalformedURLException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        } finally {            // 关闭资源            if (null != br) {                try {                    br.close();                } catch (IOException e) {                    e.printStackTrace();                }            }            if (null != os) {                try {                    os.close();                } catch (IOException e) {                    e.printStackTrace();                }            }            if (null != is) {                try {                    is.close();                } catch (IOException e) {                    e.printStackTrace();                }            }            // 断开与远程地址url的连接            connection.disconnect();        }        return result;    }    /**     * 把数组所有元素排序，并按照“参数=参数值”的模式用“&”字符拼接成字符串     * @param params 需要排序并参与字符拼接的参数组     * @return 拼接后字符串     */    public static String createLinkString(Map
     
       params) {        List
      
        keys = new ArrayList
       
        (params.keySet());        Collections.sort(keys);        StringBuilder prestr = new StringBuilder();        for (int i = 0; i < keys.size(); i++) {            String key = keys.get(i);            String value = params.get(key);            if (i == keys.size() - 1) {
   // 拼接时，不包括最后一个&字符                prestr.append(key).append("=").append(value);            } else {                prestr.append(key).append("=").append(value).append("&");            }        }        return prestr.toString();    }    public static void main(String[] args) {        String url = "http://localhost:8082/api/conf/findConfList?type=1";        String getResult = HttpUtil.doGet(url);        System.out.println(getResult);        url = "http://localhost:8082/api/core/login";        JSONObject json = new JSONObject();        json.put("key", "==g43sEvsUcbcunFv3mHkIzlHO4iiUIT R7WwXuSVKTK0yugJnZSlr6qNbxsL8OqCUAFyCDCoRKQ882m6cTTi0q9uCJsq JJvxS+8mZVRP/7lWfEVt8/N9mKplUA68SWJEPSXyz4MDeFam766KEyvqZ99d");        String postResult = HttpUtil.doPost(url, json.toJSONString());        System.out.println(postResult);        url = "http://localhost:8082/api/test/testSendForm";        Map
        
          map = new HashMap<>();        map.put("name", "测试表单请求");        String formResult = HttpUtil.doPostForm(url, map);        System.out.println(formResult);    }}

以上包括了get请求和post请求以及form表单请求

第二种方式：apache HttpClient 3.1

package com.demo.httpClient;import java.io.BufferedReader;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.io.UnsupportedEncodingException;import java.util.Iterator;import java.util.Map;import java.util.Map.Entry;import java.util.Set;import org.apache.commons.httpclient.DefaultHttpMethodRetryHandler;import org.apache.commons.httpclient.HttpClient;import org.apache.commons.httpclient.HttpStatus;import org.apache.commons.httpclient.NameValuePair;import org.apache.commons.httpclient.methods.GetMethod;import org.apache.commons.httpclient.methods.PostMethod;import org.apache.commons.httpclient.params.HttpMethodParams;public class HttpClient3 {    public static String doGet(String url) {        // 输入流        InputStream is = null;        BufferedReader br = null;        String result = null;        // 创建httpClient实例        HttpClient httpClient = new HttpClient();        // 设置http连接主机服务超时时间：15000毫秒        // 先获取连接管理器对象，再获取参数对象,再进行参数的赋值        httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(15000);        // 创建一个Get方法实例对象        GetMethod getMethod = new GetMethod(url);        // 设置get请求超时为60000毫秒        getMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT, 60000);        // 设置请求重试机制，默认重试次数：3次，参数设置为true，重试机制可用，false相反        getMethod.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, new DefaultHttpMethodRetryHandler(3, true));        try {            // 执行Get方法            int statusCode = httpClient.executeMethod(getMethod);            // 判断返回码            if (statusCode != HttpStatus.SC_OK) {                // 如果状态码返回的不是ok,说明失败了,打印错误信息                System.err.println("Method faild: " + getMethod.getStatusLine());            } else {                // 通过getMethod实例，获取远程的一个输入流                is = getMethod.getResponseBodyAsStream();                // 包装输入流                br = new BufferedReader(new InputStreamReader(is, "UTF-8"));                StringBuffer sbf = new StringBuffer();                // 读取封装的输入流                String temp = null;                while ((temp = br.readLine()) != null) {                    sbf.append(temp).append("\r\n");                }                result = sbf.toString();            }        } catch (IOException e) {            e.printStackTrace();        } finally {            // 关闭资源            if (null != br) {                try {                    br.close();                } catch (IOException e) {                    e.printStackTrace();                }            }            if (null != is) {                try {                    is.close();                } catch (IOException e) {                    e.printStackTrace();                }            }            // 释放连接            getMethod.releaseConnection();        }        return result;    }    public static String doPost(String url, Map
     
       paramMap) {        // 获取输入流        InputStream is = null;        BufferedReader br = null;        String result = null;        // 创建httpClient实例对象        HttpClient httpClient = new HttpClient();        // 设置httpClient连接主机服务器超时时间：15000毫秒        httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(15000);        // 创建post请求方法实例对象        PostMethod postMethod = new PostMethod(url);        // 设置post请求超时时间        postMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT, 60000);        NameValuePair[] nvp = null;        // 判断参数map集合paramMap是否为空        if (null != paramMap && paramMap.size() > 0) {
   // 不为空            // 创建键值参数对象数组，大小为参数的个数            nvp = new NameValuePair[paramMap.size()];            // 循环遍历参数集合map            Set
      
       
        > entrySet = paramMap.entrySet();            // 获取迭代器            Iterator
        
         
          > iterator = entrySet.iterator();            int index = 0;            while (iterator.hasNext()) {                Entry
          
            mapEntry = iterator.next(); // 从mapEntry中获取key和value创建键值对象存放到数组中 try { nvp[index] = new NameValuePair(mapEntry.getKey(), new String(mapEntry.getValue().toString().getBytes("UTF-8"), "UTF-8")); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } index++; } } // 判断nvp数组是否为空 if (null != nvp && nvp.length > 0) { // 将参数存放到requestBody对象中 postMethod.setRequestBody(nvp); } // 执行POST方法 try { int statusCode = httpClient.executeMethod(postMethod); // 判断是否成功 if (statusCode != HttpStatus.SC_OK) { System.err.println("Method faild: " + postMethod.getStatusLine()); } // 获取远程返回的数据 is = postMethod.getResponseBodyAsStream(); // 封装输入流 br = new BufferedReader(new InputStreamReader(is, "UTF-8")); StringBuffer sbf = new StringBuffer(); String temp = null; while ((temp = br.readLine()) != null) { sbf.append(temp).append("\r\n"); } result = sbf.toString(); } catch (IOException e) { e.printStackTrace(); } finally { // 关闭资源 if (null != br) { try { br.close(); } catch (IOException e) { e.printStackTrace(); } } if (null != is) { try { is.close(); } catch (IOException e) { e.printStackTrace(); } } // 释放连接 postMethod.releaseConnection(); } return result; }}

第三种方式：apache httpClient4.5

package com.mobile.utils;import com.alibaba.fastjson.JSONObject;import org.apache.commons.io.IOUtils;import org.apache.http.HttpEntity;import org.apache.http.HttpResponse;import org.apache.http.NameValuePair;import org.apache.http.client.ClientProtocolException;import org.apache.http.client.config.RequestConfig;import org.apache.http.client.entity.UrlEncodedFormEntity;import org.apache.http.client.methods.CloseableHttpResponse;import org.apache.http.client.methods.HttpGet;import org.apache.http.client.methods.HttpPost;import org.apache.http.entity.StringEntity;import org.apache.http.impl.client.CloseableHttpClient;import org.apache.http.impl.client.HttpClientBuilder;import org.apache.http.impl.client.HttpClients;import org.apache.http.message.BasicNameValuePair;import org.apache.http.util.EntityUtils;import org.apache.log4j.Logger;import java.io.*;import java.net.HttpURLConnection;import java.net.MalformedURLException;import java.net.URL;import java.nio.charset.Charset;import java.util.*;import java.util.Map.Entry;public class HttpUtil {    static Logger log = Logger.getLogger(HttpUtil.class);public static void main(String[] args) {        String url = "http://localhost:8082/api/conf/findConfList?type=1";        String getResult = HttpUtil.getData(url);        System.out.println(getResult);        url = "http://localhost:8082/api/core/login";        JSONObject json = new JSONObject();        json.put("key", "==g43sEvsUcbcunFv3mHkIzlHO4iiUIT R7WwXuSVKTK0yugJnZSlr6qNbxsL8OqCUAFyCDCoRKQ882m6cTTi0q9uCJsq JJvxS+8mZVRP/7lWfEVt8/N9mKplUA68SWJEPSXyz4MDeFam766KEyvqZ99d");        String postResult = HttpUtil.postData(url, json);        System.out.println(postResult);        url = "http://localhost:8082/api/test/testSendForm?format=json";        Map
     
       map = new HashMap<>();        map.put("name", "测试表单请求");        String formResult = HttpUtil.sendxwwwForm(url, map);        System.out.println(formResult);    }    public static String getData(String url) {        CloseableHttpClient httpClient = null;        CloseableHttpResponse response = null;        String result = "";        try {            // 通过址默认配置创建一个httpClient实例            httpClient = HttpClients.createDefault();            // 创建httpGet远程连接实例            HttpGet httpGet = new HttpGet(url);            // 设置请求头信息，鉴权            httpGet.setHeader("Authorization", "Bearer da3efcbf-0845-4fe3-8aba-ee040be542c0");            // 设置配置请求参数            RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(35000)// 连接主机服务超时时间                    .setConnectionRequestTimeout(35000)// 请求超时时间                    .setSocketTimeout(60000)// 数据读取超时时间                    .build();            // 为httpGet实例设置配置            httpGet.setConfig(requestConfig);            // 执行get请求得到返回对象            response = httpClient.execute(httpGet);            // 通过返回对象获取返回数据            HttpEntity entity = response.getEntity();            // 通过EntityUtils中的toString方法将结果转换为字符串            result = EntityUtils.toString(entity);        } catch (ClientProtocolException e) {            e.printStackTrace();        } catch (IOException e) {            e.printStackTrace();        } finally {            // 关闭资源            if (null != response) {                try {                    response.close();                } catch (IOException e) {                    e.printStackTrace();                }            }            if (null != httpClient) {                try {                    httpClient.close();                } catch (IOException e) {                    e.printStackTrace();                }            }        }        return result;    }    public static String postData(String url, Map
      
        paramMap) {        HttpClientBuilder httpClientBuilder = HttpClientBuilder.create();        HttpPost post = new HttpPost(url);        String result = "";        try (CloseableHttpClient closeableHttpClient = httpClientBuilder.build()) {            // HttpEntity entity = new StringEntity(jsonStrData);            // 修复 POST json 导致中文乱码            HttpEntity entity = new StringEntity(paramMap.toString(), "UTF-8");            post.setEntity(entity);            post.setHeader("Content-type", "application/json");            HttpResponse resp = closeableHttpClient.execute(post);            try {                InputStream respIs = resp.getEntity().getContent();                byte[] respBytes = IOUtils.toByteArray(respIs);                result = new String(respBytes, Charset.forName("UTF-8"));            } catch (Exception e) {                e.printStackTrace();            }            return result;        } catch (IOException e) {            e.printStackTrace();        }        return result;    }    /**     * form表单提交     * @param url     * @param paramMap     * @return     */    public static String sendxwwwform(String url, Map
       
         paramMap) {        CloseableHttpClient httpClient = null;        CloseableHttpResponse httpResponse = null;        String result = "";        // 创建httpClient实例        httpClient = HttpClients.createDefault();        // 创建httpPost远程连接实例        HttpPost httpPost = new HttpPost(url);        // 配置请求参数实例        RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(35000)// 设置连接主机服务超时时间                .setConnectionRequestTimeout(35000)// 设置连接请求超时时间                .setSocketTimeout(60000)// 设置读取数据连接超时时间                .build();        // 为httpPost实例设置配置        httpPost.setConfig(requestConfig);        // 设置请求头        httpPost.addHeader("Content-Type", "application/x-www-form-urlencoded");        // 封装post请求参数        if (null != paramMap && paramMap.size() > 0) {            List
        
          nvps = new ArrayList
         
          ();            // 通过map集成entrySet方法获取entity            Set
          
           
            > entrySet = paramMap.entrySet(); // 循环遍历，获取迭代器 Iterator
            
             
              > iterator = entrySet.iterator(); while (iterator.hasNext()) { Entry
              
                mapEntry = iterator.next(); nvps.add(new BasicNameValuePair(mapEntry.getKey(), mapEntry.getValue().toString())); } // 为httpPost设置封装好的请求参数 try { httpPost.setEntity(new UrlEncodedFormEntity(nvps, "UTF-8")); } catch (UnsupportedEncodingException e) { e.printStackTrace(); } } try { // httpClient对象执行post请求,并返回响应参数对象 httpResponse = httpClient.execute(httpPost); // 从响应对象中获取响应内容 HttpEntity entity = httpResponse.getEntity(); result = EntityUtils.toString(entity); } catch (ClientProtocolException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } finally { // 关闭资源 if (null != httpResponse) { try { httpResponse.close(); } catch (IOException e) { e.printStackTrace(); } } if (null != httpClient) { try { httpClient.close(); } catch (IOException e) { e.printStackTrace(); } } } return result; }}

以上包括了get请求和post请求以及form表单请求

此外还可以设置添加自定义请求头（有的接口需要登录验证）：

　　方式一：

//设置自定义请求头            if (headerMap != null) {                for (Map.Entry
     
       entry : headerMap.entrySet()) {                    connection.setRequestProperty(entry.getKey(),entry.getValue());                }            }

　　方式三：

if (headers != null) {            for (Map.Entry
     
       entry : headers.entrySet()) {                httpPost.addHeader(entry.getKey(),entry.getValue());            }        }

转载自https://www.cnblogs.com/hhhshct/p/8523697.html

测试后，稍作改动及添加

httpurlconnection和httpclient区别：

转载于:https://www.cnblogs.com/mufengforward/p/10510337.html

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