java中的http請求的封裝（GET、POST、form表單形式）

 

目前JAVA實現HTTP請求的方法用的最多的有兩種：一種是經過HTTPClient這種第三方的開源框架去實現。HTTPClient對HTTP的封裝性比較不錯，經過它基本上可以知足咱們大部分的需求，HttpClient3.1 是 org.apache.commons.httpclient下操做遠程 url的工具包，雖然已再也不更新，但實現工做中使用httpClient3.1的代碼仍是不少，HttpClient4.5是org.apache.http.client下操做遠程 url的工具包，最新的；另外一種則是經過HttpURLConnection去實現，HttpURLConnection是JAVA的標準類，是JAVA比較原生的一種實現方式。

 

第一種方式：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發送GET方法的請求
     *
     * @param httpurl
     *            請求參數用?拼接在url後邊，請求參數應該是 name1=value1&name2=value2 的形式。
     * @return result 所表明遠程資源的響應結果
     */
    public static String doGet(String httpurl) {
        HttpURLConnection connection = null;
        InputStream is = null;
        BufferedReader br = null;
        String result = null;// 返回結果字符串
        try {
            // 建立遠程url鏈接對象
            URL url = new URL(httpurl);
            // 經過遠程url鏈接對象打開一個鏈接，強轉成httpURLConnection類
            connection = (HttpURLConnection) url.openConnection();
            // 設置鏈接方式：get
            connection.setRequestMethod("GET");
            // 設置鏈接主機服務器的超時時間：15000毫秒
            connection.setConnectTimeout(15000);
            // 設置讀取遠程返回的數據時間：60000毫秒
            connection.setReadTimeout(60000);
            // 發送請求
            connection.connect();
            // 經過connection鏈接，獲取輸入流
            if (connection.getResponseCode() == 200) {
                is = connection.getInputStream();
                // 封裝輸入流is，並指定字符集
                br = new BufferedReader(new InputStreamReader(is, "UTF-8"));
                // 存放數據
                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 {
            // 關閉資源
            if (null != br) {
                try {
                    br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }

            if (null != is) {
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }

            connection.disconnect();// 關閉遠程鏈接
        }

        return result;
    }

    /**
     * 向指定 URL 發送POST方法的請求
     *
     * @param httpUrl
     *            發送請求的 URL
     * @param param
     *            請求參數應該是{"key":"==g43sEvsUcbcunFv3mHkIzlHO4iiUIT R7WwXuSVKTK0yugJnZSlr6qNbxsL8OqCUAFyCDCoRKQ882m6cTTi0q9uCJsq JJvxS+8mZVRP/7lWfEVt8/N9mKplUA68SWJEPSXyz4MDeFam766KEyvqZ99d"}的形式。
     * @return 所表明遠程資源的響應結果
     */
    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);
            // 經過遠程url鏈接對象打開鏈接
            connection = (HttpURLConnection) url.openConnection();
            // 設置鏈接請求方式
            connection.setRequestMethod("POST");
            // 設置鏈接主機服務器超時時間：15000毫秒
            connection.setConnectTimeout(15000);
            // 設置讀取主機服務器返回數據超時時間：60000毫秒
            connection.setReadTimeout(60000);

            // 默認值爲：false，當向遠程服務器傳送數據/寫數據時，須要設置爲true
            connection.setDoOutput(true);
            // 默認值爲：true，當前向遠程服務讀取數據時，設置爲true，該參數無關緊要
            connection.setDoInput(true);
            // 設置傳入參數的格式:請求參數應該是 name1=value1&name2=value2 的形式。
            connection.setRequestProperty("Content-Type", "application/json");
            // 設置鑑權信息：Authorization: Bearer da3efcbf-0845-4fe3-8aba-ee040be542c0
            //connection.setRequestProperty("Authorization", "Bearer da3efcbf-0845-4fe3-8aba-ee040be542c0");
            // 經過鏈接對象獲取一個輸出流
            os = connection.getOutputStream();
            // 經過輸出流對象將參數寫出去/傳輸出去,它是經過字節數組寫出的
            os.write(param.getBytes());
            // 經過鏈接對象獲取一個輸入流，向遠程讀取
            if (connection.getResponseCode() == 200) {

                is = connection.getInputStream();
                // 對輸入流對象進行包裝:charset根據工做項目組的要求來設置
                br = new BufferedReader(new InputStreamReader(is, "UTF-8"));

                StringBuffer sbf = new StringBuffer();
                String temp = null;
                // 循環遍歷一行一行讀取數據
                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 {
            // 關閉資源
            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();
                }
            }
            // 斷開與遠程地址url的鏈接
            connection.disconnect();
        }
        return result;
    }

    /**
     *
     * @param httpUrl  請求的url
     * @param param  form表單的參數（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);
            // 經過遠程url鏈接對象打開鏈接
            connection = (HttpURLConnection) url.openConnection();
            // 設置鏈接請求方式
            connection.setRequestMethod("POST");
            // 設置鏈接主機服務器超時時間：15000毫秒
            connection.setConnectTimeout(15000);
            // 設置讀取主機服務器返回數據超時時間：60000毫秒
            connection.setReadTimeout(60000);

            // 默認值爲：false，當向遠程服務器傳送數據/寫數據時，須要設置爲true
            connection.setDoOutput(true);
            // 默認值爲：true，當前向遠程服務讀取數據時，設置爲true，該參數無關緊要
            connection.setDoInput(true);
            // 設置傳入參數的格式:請求參數應該是 name1=value1&name2=value2 的形式。
            connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
            // 設置鑑權信息：Authorization: Bearer da3efcbf-0845-4fe3-8aba-ee040be542c0
            //connection.setRequestProperty("Authorization", "Bearer da3efcbf-0845-4fe3-8aba-ee040be542c0");
            // 經過鏈接對象獲取一個輸出流
            os = connection.getOutputStream();
            // 經過輸出流對象將參數寫出去/傳輸出去,它是經過字節數組寫出的(form表單形式的參數實質也是key,value值的拼接，相似於get請求參數的拼接)
            os.write(createLinkString(param).getBytes());
            // 經過鏈接對象獲取一個輸入流，向遠程讀取
            if (connection.getResponseCode() == 200) {

                is = connection.getInputStream();
                // 對輸入流對象進行包裝:charset根據工做項目組的要求來設置
                br = new BufferedReader(new InputStreamReader(is, "UTF-8"));

                StringBuffer sbf = new StringBuffer();
                String temp = null;
                // 循環遍歷一行一行讀取數據
                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 {
            // 關閉資源
            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();
                }
            }
            // 斷開與遠程地址url的鏈接
            connection.disconnect();
        }
        return result;
    }
    /**
     * 把數組全部元素排序，並按照「參數=參數值」的模式用「&」字符拼接成字符串
     * @param params 須要排序並參與字符拼接的參數組
     * @return 拼接後字符串
     */
    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) {// 拼接時，不包括最後一個&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", "測試表單請求");
        String formResult = HttpUtil.doPostForm(url, map);
        System.out.println(formResult);

    }

}

以上包括了get請求和post請求以及form表單請求 

 

第二種方式：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) {
        // 輸入流
        InputStream is = null;
        BufferedReader br = null;
        String result = null;
        // 建立httpClient實例
        HttpClient httpClient = new HttpClient();
        // 設置http鏈接主機服務超時時間：15000毫秒
        // 先獲取鏈接管理器對象，再獲取參數對象,再進行參數的賦值
        httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(15000);
        // 建立一個Get方法實例對象
        GetMethod getMethod = new GetMethod(url);
        // 設置get請求超時爲60000毫秒
        getMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT, 60000);
        // 設置請求重試機制，默認重試次數：3次，參數設置爲true，重試機制可用，false相反
        getMethod.getParams().setParameter(HttpMethodParams.RETRY_HANDLER, new DefaultHttpMethodRetryHandler(3, true));
        try {
            // 執行Get方法
            int statusCode = httpClient.executeMethod(getMethod);
            // 判斷返回碼
            if (statusCode != HttpStatus.SC_OK) {
                // 若是狀態碼返回的不是ok,說明失敗了,打印錯誤信息
                System.err.println("Method faild: " + getMethod.getStatusLine());
            } else {
                // 經過getMethod實例，獲取遠程的一個輸入流
                is = getMethod.getResponseBodyAsStream();
                // 包裝輸入流
                br = new BufferedReader(new InputStreamReader(is, "UTF-8"));

                StringBuffer sbf = new StringBuffer();
                // 讀取封裝的輸入流
                String temp = null;
                while ((temp = br.readLine()) != null) {
                    sbf.append(temp).append("\r\n");
                }

                result = sbf.toString();
            }

        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            // 關閉資源
            if (null != br) {
                try {
                    br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (null != is) {
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            // 釋放鏈接
            getMethod.releaseConnection();
        }
        return result;
    }

    public static String doPost(String url, Map<String, Object> paramMap) {
        // 獲取輸入流
        InputStream is = null;
        BufferedReader br = null;
        String result = null;
        // 建立httpClient實例對象
        HttpClient httpClient = new HttpClient();
        // 設置httpClient鏈接主機服務器超時時間：15000毫秒
        httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(15000);
        // 建立post請求方法實例對象
        PostMethod postMethod = new PostMethod(url);
        // 設置post請求超時時間
        postMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT, 60000);

        NameValuePair[] nvp = null;
        // 判斷參數map集合paramMap是否爲空
        if (null != paramMap && paramMap.size() > 0) {// 不爲空
            // 建立鍵值參數對象數組，大小爲參數的個數
            nvp = new NameValuePair[paramMap.size()];
            // 循環遍歷參數集合map
            Set<Entry<String, Object>> entrySet = paramMap.entrySet();
            // 獲取迭代器
            Iterator<Entry<String, Object>> iterator = entrySet.iterator();

            int index = 0;
            while (iterator.hasNext()) {
                Entry<String, Object> mapEntry = iterator.next();
                // 從mapEntry中獲取key和value建立鍵值對象存放到數組中
                try {
                    nvp[index] = new NameValuePair(mapEntry.getKey(),
                            new String(mapEntry.getValue().toString().getBytes("UTF-8"), "UTF-8"));
                } catch (UnsupportedEncodingException e) {
                    e.printStackTrace();
                }
                index++;
            }
        }
        // 判斷nvp數組是否爲空
        if (null != nvp && nvp.length > 0) {
            // 將參數存放到requestBody對象中
            postMethod.setRequestBody(nvp);
        }
        // 執行POST方法
        try {
            int statusCode = httpClient.executeMethod(postMethod);
            // 判斷是否成功
            if (statusCode != HttpStatus.SC_OK) {
                System.err.println("Method faild: " + postMethod.getStatusLine());
            }
            // 獲取遠程返回的數據
            is = postMethod.getResponseBodyAsStream();
            // 封裝輸入流
            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 {
            // 關閉資源
            if (null != br) {
                try {
                    br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (null != is) {
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            // 釋放鏈接
            postMethod.releaseConnection();
        }
        return result;
    }
}

 

第三種方式：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", "測試表單請求");
        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 {
            // 經過址默認配置建立一個httpClient實例
            httpClient = HttpClients.createDefault();
            // 建立httpGet遠程鏈接實例
            HttpGet httpGet = new HttpGet(url);
            // 設置請求頭信息，鑑權
            httpGet.setHeader("Authorization", "Bearer da3efcbf-0845-4fe3-8aba-ee040be542c0");
            // 設置配置請求參數
            RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(35000)// 鏈接主機服務超時時間
                    .setConnectionRequestTimeout(35000)// 請求超時時間
                    .setSocketTimeout(60000)// 數據讀取超時時間
                    .build();
            // 爲httpGet實例設置配置
            httpGet.setConfig(requestConfig);
            // 執行get請求獲得返回對象
            response = httpClient.execute(httpGet);
            // 經過返回對象獲取返回數據
            HttpEntity entity = response.getEntity();
            // 經過EntityUtils中的toString方法將結果轉換爲字符串
            result = EntityUtils.toString(entity);
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            // 關閉資源
            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);
            // 修復 POST json 致使中文亂碼
            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表單提交
     * @param url
     * @param paramMap
     * @return
     */
    public static String sendxwwwform(String url, Map<String, Object> paramMap) {
        CloseableHttpClient httpClient = null;
        CloseableHttpResponse httpResponse = null;
        String result = "";
        // 建立httpClient實例
        httpClient = HttpClients.createDefault();
        // 建立httpPost遠程鏈接實例
        HttpPost httpPost = new HttpPost(url);
        // 配置請求參數實例
        RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(35000)// 設置鏈接主機服務超時時間
                .setConnectionRequestTimeout(35000)// 設置鏈接請求超時時間
                .setSocketTimeout(60000)// 設置讀取數據鏈接超時時間
                .build();
        // 爲httpPost實例設置配置
        httpPost.setConfig(requestConfig);
        // 設置請求頭
        httpPost.addHeader("Content-Type", "application/x-www-form-urlencoded");
        // 封裝post請求參數
        if (null != paramMap && paramMap.size() > 0) {
            List<NameValuePair> nvps = new ArrayList<NameValuePair>();
            // 經過map集成entrySet方法獲取entity
            Set<Entry<String, Object>> entrySet = paramMap.entrySet();
            // 循環遍歷，獲取迭代器
            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()));
            }

            // 爲httpPost設置封裝好的請求參數
            try {
                httpPost.setEntity(new UrlEncodedFormEntity(nvps, "UTF-8"));
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            }
        }
        try {
            // httpClient對象執行post請求,並返回響應參數對象
            httpResponse = httpClient.execute(httpPost);
            // 從響應對象中獲取響應內容
            HttpEntity entity = httpResponse.getEntity();
            result = EntityUtils.toString(entity);
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            // 關閉資源
            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請求和post請求以及form表單請求 

 

此外還能夠設置添加自定義請求頭（有的接口須要登陸驗證）：

　　方式一：

 //設置自定義請求頭
            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());
            }
        }

　　

轉載自https://www.cnblogs.com/hhhshct/p/8523697.html

測試後，稍做改動及添加

httpurlconnection和httpclient區別：http://www.javashuo.com/article/p-nwxfdsxd-cr.html