java 實現http請求的三種方式
阿新 • • 發佈:2018-12-30
目前JAVA實現HTTP請求的方法用的最多的有兩種:一種是通過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,通過它基本上能夠滿足我們大部分的需求,HttpClient3.1 是 org.apache.commons.httpclient下操作遠端 url的工具包,雖然已不再更新,但實現工作中使用httpClient3.1的程式碼還是很多,HttpClient4.5是org.apache.http.client下操作遠端 url的工具包,最新的;另一種則是通過HttpURLConnection去實現,HttpURLConnection是JAVA的標準類,是JAVA比較原生的一種實現方式。
自己在工作中三種方式都用到過,總結一下分享給大家,也方便自己以後使用,話不多說上程式碼。
第一種方式:java原生HttpURLConnection
package com.powerX.httpClient;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
public class HttpClient {
public static String doGet(String httpurl) {
HttpURLConnection connection = null;
InputStream is = null;
BufferedReader br = null;
String result = null;// 返回結果字串
try {
// 建立遠端url連線物件
URL url = new URL(httpurl);
// 通過遠端url連線物件開啟一個連線,強轉成httpURLConnection類
connection = (HttpURLConnection) url.openConnection();
// 設定連線方式:get
connection.setRequestMethod("GET");
// 設定連線主機伺服器的超時時間:15000毫秒
connection.setConnectTimeout(15000);
// 設定讀取遠端返回的資料時間:60000毫秒
connection.setReadTimeout(60000);
// 傳送請求
connection.connect();
// 通過connection連線,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"));
// 存放資料
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();// 關閉遠端連線
}
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);
// 通過遠端url連線物件開啟連線
connection = (HttpURLConnection) url.openConnection();
// 設定連線請求方式
connection.setRequestMethod("POST");
// 設定連線主機伺服器超時時間:15000毫秒
connection.setConnectTimeout(15000);
// 設定讀取主機伺服器返回資料超時時間:60000毫秒
connection.setReadTimeout(60000);
// 預設值為:false,當向遠端伺服器傳送資料/寫資料時,需要設定為true
connection.setDoOutput(true);
// 預設值為:true,當前向遠端服務讀取資料時,設定為true,該引數可有可無
connection.setDoInput(true);
// 設定傳入引數的格式:請求引數應該是 name1=value1&name2=value2 的形式。
connection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
// 設定鑑權資訊:Authorization: Bearer da3efcbf-0845-4fe3-8aba-ee040be542c0
connection.setRequestProperty("Authorization", "Bearer da3efcbf-0845-4fe3-8aba-ee040be542c0");
// 通過連線物件獲取一個輸出流
os = connection.getOutputStream();
// 通過輸出流物件將引數寫出去/傳輸出去,它是通過位元組陣列寫出的
os.write(param.getBytes());
// 通過連線物件獲取一個輸入流,向遠端讀取
if (connection.getResponseCode() == 200) {
is = connection.getInputStream();
// 對輸入流物件進行包裝:charset根據工作專案組的要求來設定
br = new BufferedReader(new InputStreamReader(is, "UTF-8"));
StringBuffer sbf = new StringBuffer();
String temp = null;
// 迴圈遍歷一行一行讀取資料
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();
}
}
// 斷開與遠端地址url的連線
connection.disconnect();
}
return result;
}
}
第二種方式:apache HttpClient3.1
package com.powerX.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例項
HttpClient httpClient = new HttpClient();
// 設定http連線主機服務超時時間:15000毫秒
// 先獲取連線管理器物件,再獲取引數物件,再進行引數的賦值
httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(15000);
// 建立一個Get方法例項物件
GetMethod getMethod = new GetMethod(url);
// 設定get請求超時為60000毫秒
getMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT, 60000);
// 設定請求重試機制,預設重試次數:3次,引數設定為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,列印錯誤資訊
System.err.println("Method faild: " + getMethod.getStatusLine());
} else {
// 通過getMethod例項,獲取遠端的一個輸入流
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();
}
}
// 釋放連線
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例項物件
HttpClient httpClient = new HttpClient();
// 設定httpClient連線主機伺服器超時時間:15000毫秒
httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(15000);
// 建立post請求方法例項物件
PostMethod postMethod = new PostMethod(url);
// 設定post請求超時時間
postMethod.getParams().setParameter(HttpMethodParams.SO_TIMEOUT, 60000);
NameValuePair[] nvp = null;
// 判斷引數map集合paramMap是否為空
if (null != paramMap && paramMap.size() > 0) {// 不為空
// 建立鍵值引數物件陣列,大小為引數的個數
nvp = new NameValuePair[paramMap.size()];
// 迴圈遍歷引數集合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建立鍵值物件存放到陣列中
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陣列是否為空
if (null != nvp && nvp.length > 0) {
// 將引數存放到requestBody物件中
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());
}
// 獲取遠端返回的資料
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();
}
}
// 釋放連線
postMethod.releaseConnection();
}
return result;
}
}
第三種方式:apache httpClient4.5
package com.powerX.httpClient;
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;
public class HttpClient4 {
public static String doGet(String url) {
CloseableHttpClient httpClient = null;
CloseableHttpResponse response = null;
String result = "";
try {
// 通過址預設配置建立一個httpClient例項
httpClient = HttpClients.createDefault();
// 建立httpGet遠端連線例項
HttpGet httpGet = new HttpGet(url);
// 設定請求頭資訊,鑑權
httpGet.setHeader("Authorization", "Bearer da3efcbf-0845-4fe3-8aba-ee040be542c0");
// 設定配置請求引數
RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(35000)// 連線主機服務超時時間
.setConnectionRequestTimeout(35000)// 請求超時時間
.setSocketTimeout(60000)// 資料讀取超時時間
.build();
// 為httpGet例項設定配置
httpGet.setConfig(requestConfig);
// 執行get請求得到返回物件
response = httpClient.execute(httpGet);
// 通過返回物件獲取返回資料
HttpEntity entity = response.getEntity();
// 通過EntityUtils中的toString方法將結果轉換為字串
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 = "";
// 建立httpClient例項
httpClient = HttpClients.createDefault();
// 建立httpPost遠端連線例項
HttpPost httpPost = new HttpPost(url);
// 配置請求引數例項
RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(35000)// 設定連線主機服務超時時間
.setConnectionRequestTimeout(35000)// 設定連線請求超時時間
.setSocketTimeout(60000)// 設定讀取資料連線超時時間
.build();
// 為httpPost例項設定配置
httpPost.setConfig(requestConfig);
// 設定請求頭
httpPost.addHeader("Content-Type", "application/x-www-form-urlencoded");
// 封裝post請求引數
if (null != paramMap && paramMap.size() > 0) {
List<NameValuePair> nvps = new ArrayList<NameValuePair>();
// 通過map整合entrySet方法獲取entity
Set<Entry<String, Object>> entrySet = paramMap.entrySet();
// 迴圈遍歷,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()));
}
// 為httpPost設定封裝好的請求引數
try {
httpPost.setEntity(new UrlEncodedFormEntity(nvps, "UTF-8"));
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
}
try {
// httpClient物件執行post請求,並返回響應引數物件
httpResponse = httpClient.execute(httpPost);
// 從響應物件中獲取響應內容
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;
}
}
有時候我們在使用post請求時,可能傳入的引數是json或者其他格式,此時我們則需要更改請求頭及引數的設定資訊,以httpClient4.5為例,更改下面兩列配置:httpPost.setEntity(new StringEntity(“你的json串”)); httpPost.addHeader(“Content-Type”, “application/json”)。