java中的http请求的封装（GET、POST、form表单形式）

时间：2023-03-09 19:56:25
java中的http请求的封装（GET、POST、form表单形式）

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<String, String> params) {

        List<String> keys = new ArrayList<String>(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<String,String> 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<String, Object> 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<Entry<String, Object>> entrySet = paramMap.entrySet();

            // 获取迭代器

            Iterator<Entry<String, Object>> iterator = entrySet.iterator();

            int index = 0;

            while (iterator.hasNext()) {

                Entry<String, Object> 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<String, Object> 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<String, Object> 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<String, Object> 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<NameValuePair> nvps = new ArrayList<NameValuePair>();

            // 通过map集成entrySet方法获取entity

            Set<Entry<String, Object>> entrySet = paramMap.entrySet();

            // 循环遍历，获取迭代器

            Iterator<Entry<String, Object>> iterator = entrySet.iterator();

            while (iterator.hasNext()) {

                Entry<String, Object> 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<String, String> entry : headerMap.entrySet()) {

                    connection.setRequestProperty(entry.getKey(),entry.getValue());

                }

            }

　　方式三：

if (headers != null) {

            for (Map.Entry<String, String> 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：https://www.cnblogs.com/liushuibufu/p/4140913.html

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