發送http請求來調用其他微服務的方法

第一種:原生 HttpURLConnection

package com.sid.http.util;
 
import java.io.*;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
 
/**
 * @program: springboot
 * @description: java原生HttpURLConnection
 * @author: Sid
 * @date: 2018-11-01 17:36
 * @since: 1.0
 **/
public class HttpUtil {
 
    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 {
            // 創建遠程url連接對象
            URL url = new URL(httpurl);
            // 通過遠程url連接對象打開一個連接，強轉成httpURLConnection類
            connection = (HttpURLConnection) url.openConnection();
            // 設置連接方式：get
            connection.setRequestMethod("GET");
            // 設置連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();
            // 通過connection連接，獲取輸入流
            getResponse( connection, br, is, result);
        } 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();// 關閉遠程連接
        }
 
        return result;
    }
 
    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);
            // 通過遠程url連接對象打開連接
            connection = (HttpURLConnection) url.openConnection();
            // 設置連接請求方式
            connection.setRequestMethod("POST");
            // 設置連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，需要設置爲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，該參數可有可無
            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", "");
            // 通過連接對象獲取一個輸出流
            os = connection.getOutputStream();
            // 通過輸出流對象將參數寫出去/傳輸出去,它是通過字節數組寫出的
            os.write(param.getBytes());
            // 通過連接對象獲取一個輸入流，向遠程讀取
            getResponse( connection, br, is, result);
        } 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的連接
            connection.disconnect();
        }
        return result;
    }
 
 
    // 通過connection連接，獲取輸入流
    private static void getResponse(HttpURLConnection connection,BufferedReader br,InputStream is,String result) throws IOException {
        // 通過connection連接，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();
        }
    }
}

第二種方式：使用apache HttpClient3.1

<dependency>
        <groupId>commons-httpclient</groupId>
        <artifactId>commons-httpclient</artifactId>
        <version>3.1</version>
    </dependency>

package com.sid.http.util;
 
import java.io.IOException;
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;
 
/**
 * @program: springboot
 * @description:    apache HttpClient3.1
 * @author: Sid
 * @date: 2018-11-01 17:44
 * @since: 1.0
 **/
public class HttpUtil3 {
    public static String doGet(String url) {
 
        String result = null;
        // 創建httpClient實例
        HttpClient httpClient = new HttpClient();
        // 設置http連接主機服務超時時間：15000毫秒
        // 先獲取連接管理器對象，再獲取參數對象,再進行參數的賦值
        httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(15000);
        // 創建一個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) {
                // 如果狀態碼返回的不是ok,說明失敗了,打印錯誤信息
                System.err.println("Method faild: " + getMethod.getStatusLine());
            } else {
                // 通過getMethod實例，獲取返回內容
                String responseBodyAsString = getMethod.getResponseBodyAsString();
 
                result = responseBodyAsString;
            }
 
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            // 釋放連接
            getMethod.releaseConnection();
        }
        return result;
    }
 
    public static String doPost(String url, Map<String, Object> paramMap) {
        String result = null;
        // 創建httpClient實例對象
        HttpClient httpClient = new HttpClient();
        // 設置httpClient連接主機服務器超時時間：15000毫秒
        httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(15000);
        // 創建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
            // 創建鍵值參數對象數組，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創建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
            String responseBodyAsString = postMethod.getResponseBodyAsString();
 
 
            result = responseBodyAsString;
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            // 釋放連接
            postMethod.releaseConnection();
        }
        return result;
    }
}

第三種方式：使用apache http 4

    <dependency>
        <groupId>org.apache.httpcomponents</groupId>
        <artifactId>httpclient</artifactId>
        <version>4.5.2</version>
    </dependency>

package com.sid.http.util;
 
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
 
import org.apache.http.HttpEntity;
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.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;
 
/**
 * @program: springboot
 * @description: apache http 4
 * @author: Sid
 * @date: 2018-11-01 17:55
 * @since: 1.0
 **/
public class HttpUtil4 {
    public static String doGet(String url) {
        CloseableHttpClient httpClient = null;
        CloseableHttpResponse response = null;
        String result = "";
        try {
            // 通過址默認配置創建一個httpClient實例
            httpClient = HttpClients.createDefault();
            // 創建httpGet遠程連接實例
            HttpGet httpGet = new HttpGet(url);
            // 設置請求頭信息，鑑權
            //httpGet.setHeader("Authorization", "");
            // 設置配置請求參數
            RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(35000)// 連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請求得到返回對象
            response = httpClient.execute(httpGet);
            // 通過返回對象獲取返回數據
            HttpEntity entity = response.getEntity();
            // 通過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 doPost(String url, Map<String, Object> paramMap) {
        CloseableHttpClient httpClient = null;
        CloseableHttpResponse httpResponse = null;
        String result = "";
        // 創建httpClient實例
        httpClient = HttpClients.createDefault();
        // 創建httpPost遠程連接實例
        HttpPost httpPost = new HttpPost(url);
        // 配置請求參數實例
        RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(35000)// 設置連接主機服務超時時間
                .setConnectionRequestTimeout(35000)// 設置連接請求超時時間
                .setSocketTimeout(60000)// 設置讀取數據連接超時時間
                .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<>();
            // 通過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;
    }
}

總結

以上這三種方式都可以在boot項目中使用，但要注意get 和post請求的傳參問題！！！！！