java中的常見幾種發(fā)送http請求實例
更新時間：2024年11月08日 09:14:20 作者：北極熊不在北極
在Java編程中,發(fā)送HTTP請求是一個常見需求,常用的方法有四種：HttpURLConnection、URLConnection、HttpClient以及Socket,其中,使用HttpClient方式時,需要添加額外的庫支持
java常見幾種發(fā)送http請求實例
<span style="font-family: Arial, Helvetica, sans-serif;">import java.io.BufferedReader;</span>
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.io.UnsupportedEncodingException;
import java.net.HttpURLConnection;
import java.net.Socket;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
/**
* @Description:發(fā)送http請求幫助類
* @author:liuyc
* @time:2016年5月17日 下午3:25:32
*/
public class HttpClientHelper {
/**
* @Description:使用HttpURLConnection發(fā)送post請求
* @author:liuyc
* @time:2016年5月17日 下午3:26:07
*/
public static String sendPost(String urlParam, Map<String, Object> params, String charset) {
StringBuffer resultBuffer = null;
// 構建請求參數(shù)
StringBuffer sbParams = new StringBuffer();
if (params != null && params.size() > 0) {
for (Entry<String, Object> e : params.entrySet()) {
sbParams.append(e.getKey());
sbParams.append("=");
sbParams.append(e.getValue());
sbParams.append("&");
}
}
HttpURLConnection con = null;
OutputStreamWriter osw = null;
BufferedReader br = null;
// 發(fā)送請求
try {
URL url = new URL(urlParam);
con = (HttpURLConnection) url.openConnection();
con.setRequestMethod("POST");
con.setDoOutput(true);
con.setDoInput(true);
con.setUseCaches(false);
con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
if (sbParams != null && sbParams.length() > 0) {
osw = new OutputStreamWriter(con.getOutputStream(), charset);
osw.write(sbParams.substring(0, sbParams.length() - 1));
osw.flush();
}
// 讀取返回內(nèi)容
resultBuffer = new StringBuffer();
int contentLength = Integer.parseInt(con.getHeaderField("Content-Length"));
if (contentLength > 0) {
br = new BufferedReader(new InputStreamReader(con.getInputStream(), charset));
String temp;
while ((temp = br.readLine()) != null) {
resultBuffer.append(temp);
}
}
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
if (osw != null) {
try {
osw.close();
} catch (IOException e) {
osw = null;
throw new RuntimeException(e);
} finally {
if (con != null) {
con.disconnect();
con = null;
}
}
}
if (br != null) {
try {
br.close();
} catch (IOException e) {
br = null;
throw new RuntimeException(e);
} finally {
if (con != null) {
con.disconnect();
con = null;
}
}
}
}
return resultBuffer.toString();
}
/**
* @Description:使用URLConnection發(fā)送post
* @author:liuyc
* @time:2016年5月17日 下午3:26:52
*/
public static String sendPost2(String urlParam, Map<String, Object> params, String charset) {
StringBuffer resultBuffer = null;
// 構建請求參數(shù)
StringBuffer sbParams = new StringBuffer();
if (params != null && params.size() > 0) {
for (Entry<String, Object> e : params.entrySet()) {
sbParams.append(e.getKey());
sbParams.append("=");
sbParams.append(e.getValue());
sbParams.append("&");
}
}
URLConnection con = null;
OutputStreamWriter osw = null;
BufferedReader br = null;
try {
URL realUrl = new URL(urlParam);
// 打開和URL之間的連接
con = realUrl.openConnection();
// 設置通用的請求屬性
con.setRequestProperty("accept", "*/*");
con.setRequestProperty("connection", "Keep-Alive");
con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
con.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
// 發(fā)送POST請求必須設置如下兩行
con.setDoOutput(true);
con.setDoInput(true);
// 獲取URLConnection對象對應的輸出流
osw = new OutputStreamWriter(con.getOutputStream(), charset);
if (sbParams != null && sbParams.length() > 0) {
// 發(fā)送請求參數(shù)
osw.write(sbParams.substring(0, sbParams.length() - 1));
// flush輸出流的緩沖
osw.flush();
}
// 定義BufferedReader輸入流來讀取URL的響應
resultBuffer = new StringBuffer();
int contentLength = Integer.parseInt(con.getHeaderField("Content-Length"));
if (contentLength > 0) {
br = new BufferedReader(new InputStreamReader(con.getInputStream(), charset));
String temp;
while ((temp = br.readLine()) != null) {
resultBuffer.append(temp);
}
}
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
if (osw != null) {
try {
osw.close();
} catch (IOException e) {
osw = null;
throw new RuntimeException(e);
}
}
if (br != null) {
try {
br.close();
} catch (IOException e) {
br = null;
throw new RuntimeException(e);
}
}
}
return resultBuffer.toString();
}
/**
* @Description:發(fā)送get請求保存下載文件
* @author:liuyc
* @time:2016年5月17日 下午3:27:29
*/
public static void sendGetAndSaveFile(String urlParam, Map<String, Object> params, String fileSavePath) {
// 構建請求參數(shù)
StringBuffer sbParams = new StringBuffer();
if (params != null && params.size() > 0) {
for (Entry<String, Object> entry : params.entrySet()) {
sbParams.append(entry.getKey());
sbParams.append("=");
sbParams.append(entry.getValue());
sbParams.append("&");
}
}
HttpURLConnection con = null;
BufferedReader br = null;
FileOutputStream os = null;
try {
URL url = null;
if (sbParams != null && sbParams.length() > 0) {
url = new URL(urlParam + "?" + sbParams.substring(0, sbParams.length() - 1));
} else {
url = new URL(urlParam);
}
con = (HttpURLConnection) url.openConnection();
con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
con.connect();
InputStream is = con.getInputStream();
os = new FileOutputStream(fileSavePath);
byte buf[] = new byte[1024];
int count = 0;
while ((count = is.read(buf)) != -1) {
os.write(buf, 0, count);
}
os.flush();
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
if (os != null) {
try {
os.close();
} catch (IOException e) {
os = null;
throw new RuntimeException(e);
} finally {
if (con != null) {
con.disconnect();
con = null;
}
}
}
if (br != null) {
try {
br.close();
} catch (IOException e) {
br = null;
throw new RuntimeException(e);
} finally {
if (con != null) {
con.disconnect();
con = null;
}
}
}
}
}
/**
* @Description:使用HttpURLConnection發(fā)送get請求
* @author:liuyc
* @time:2016年5月17日 下午3:27:29
*/
public static String sendGet(String urlParam, Map<String, Object> params, String charset) {
StringBuffer resultBuffer = null;
// 構建請求參數(shù)
StringBuffer sbParams = new StringBuffer();
if (params != null && params.size() > 0) {
for (Entry<String, Object> entry : params.entrySet()) {
sbParams.append(entry.getKey());
sbParams.append("=");
sbParams.append(entry.getValue());
sbParams.append("&");
}
}
HttpURLConnection con = null;
BufferedReader br = null;
try {
URL url = null;
if (sbParams != null && sbParams.length() > 0) {
url = new URL(urlParam + "?" + sbParams.substring(0, sbParams.length() - 1));
} else {
url = new URL(urlParam);
}
con = (HttpURLConnection) url.openConnection();
con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
con.connect();
resultBuffer = new StringBuffer();
br = new BufferedReader(new InputStreamReader(con.getInputStream(), charset));
String temp;
while ((temp = br.readLine()) != null) {
resultBuffer.append(temp);
}
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
if (br != null) {
try {
br.close();
} catch (IOException e) {
br = null;
throw new RuntimeException(e);
} finally {
if (con != null) {
con.disconnect();
con = null;
}
}
}
}
return resultBuffer.toString();
}
/**
* @Description:使用URLConnection發(fā)送get請求
* @author:liuyc
* @time:2016年5月17日 下午3:27:58
*/
public static String sendGet2(String urlParam, Map<String, Object> params, String charset) {
StringBuffer resultBuffer = null;
// 構建請求參數(shù)
StringBuffer sbParams = new StringBuffer();
if (params != null && params.size() > 0) {
for (Entry<String, Object> entry : params.entrySet()) {
sbParams.append(entry.getKey());
sbParams.append("=");
sbParams.append(entry.getValue());
sbParams.append("&");
}
}
BufferedReader br = null;
try {
URL url = null;
if (sbParams != null && sbParams.length() > 0) {
url = new URL(urlParam + "?" + sbParams.substring(0, sbParams.length() - 1));
} else {
url = new URL(urlParam);
}
URLConnection con = url.openConnection();
// 設置請求屬性
con.setRequestProperty("accept", "*/*");
con.setRequestProperty("connection", "Keep-Alive");
con.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
con.setRequestProperty("user-agent", "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
// 建立連接
con.connect();
resultBuffer = new StringBuffer();
br = new BufferedReader(new InputStreamReader(con.getInputStream(), charset));
String temp;
while ((temp = br.readLine()) != null) {
resultBuffer.append(temp);
}
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
if (br != null) {
try {
br.close();
} catch (IOException e) {
br = null;
throw new RuntimeException(e);
}
}
}
return resultBuffer.toString();
}
/**
* @Description:使用HttpClient發(fā)送post請求
* @author:liuyc
* @time:2016年5月17日 下午3:28:23
*/
public static String httpClientPost(String urlParam, Map<String, Object> params, String charset) {
StringBuffer resultBuffer = null;
HttpClient client = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(urlParam);
// 構建請求參數(shù)
List<NameValuePair> list = new ArrayList<NameValuePair>();
Iterator<Entry<String, Object>> iterator = params.entrySet().iterator();
while (iterator.hasNext()) {
Entry<String, Object> elem = iterator.next();
list.add(new BasicNameValuePair(elem.getKey(), String.valueOf(elem.getValue())));
}
BufferedReader br = null;
try {
if (list.size() > 0) {
UrlEncodedFormEntity entity = new UrlEncodedFormEntity(list, charset);
httpPost.setEntity(entity);
}
HttpResponse response = client.execute(httpPost);
// 讀取服務器響應數(shù)據(jù)
resultBuffer = new StringBuffer();
br = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
String temp;
while ((temp = br.readLine()) != null) {
resultBuffer.append(temp);
}
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
if (br != null) {
try {
br.close();
} catch (IOException e) {
br = null;
throw new RuntimeException(e);
}
}
}
return resultBuffer.toString();
}
/**
* @Description:使用HttpClient發(fā)送get請求
* @author:liuyc
* @time:2016年5月17日 下午3:28:56
*/
public static String httpClientGet(String urlParam, Map<String, Object> params, String charset) {
StringBuffer resultBuffer = null;
HttpClient client = new DefaultHttpClient();
BufferedReader br = null;
// 構建請求參數(shù)
StringBuffer sbParams = new StringBuffer();
if (params != null && params.size() > 0) {
for (Entry<String, Object> entry : params.entrySet()) {
sbParams.append(entry.getKey());
sbParams.append("=");
try {
sbParams.append(URLEncoder.encode(String.valueOf(entry.getValue()), charset));
} catch (UnsupportedEncodingException e) {
throw new RuntimeException(e);
}
sbParams.append("&");
}
}
if (sbParams != null && sbParams.length() > 0) {
urlParam = urlParam + "?" + sbParams.substring(0, sbParams.length() - 1);
}
HttpGet httpGet = new HttpGet(urlParam);
try {
HttpResponse response = client.execute(httpGet);
// 讀取服務器響應數(shù)據(jù)
br = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
String temp;
resultBuffer = new StringBuffer();
while ((temp = br.readLine()) != null) {
resultBuffer.append(temp);
}
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
if (br != null) {
try {
br.close();
} catch (IOException e) {
br = null;
throw new RuntimeException(e);
}
}
}
return resultBuffer.toString();
}
/**
* @Description:使用socket發(fā)送post請求
* @author:liuyc
* @time:2016年5月18日 上午9:26:22
*/
public static String sendSocketPost(String urlParam, Map<String, Object> params, String charset) {
String result = "";
// 構建請求參數(shù)
StringBuffer sbParams = new StringBuffer();
if (params != null && params.size() > 0) {
for (Entry<String, Object> entry : params.entrySet()) {
sbParams.append(entry.getKey());
sbParams.append("=");
sbParams.append(entry.getValue());
sbParams.append("&");
}
}
Socket socket = null;
OutputStreamWriter osw = null;
InputStream is = null;
try {
URL url = new URL(urlParam);
String host = url.getHost();
int port = url.getPort();
if (-1 == port) {
port = 80;
}
String path = url.getPath();
socket = new Socket(host, port);
StringBuffer sb = new StringBuffer();
sb.append("POST " + path + " HTTP/1.1\r\n");
sb.append("Host: " + host + "\r\n");
sb.append("Connection: Keep-Alive\r\n");
sb.append("Content-Type: application/x-www-form-urlencoded; charset=utf-8 \r\n");
sb.append("Content-Length: ").append(sb.toString().getBytes().length).append("\r\n");
// 這里一個回車換行，表示消息頭寫完，不然服務器會繼續(xù)等待
sb.append("\r\n");
if (sbParams != null && sbParams.length() > 0) {
sb.append(sbParams.substring(0, sbParams.length() - 1));
}
osw = new OutputStreamWriter(socket.getOutputStream());
osw.write(sb.toString());
osw.flush();
is = socket.getInputStream();
String line = null;
// 服務器響應體數(shù)據(jù)長度
int contentLength = 0;
// 讀取http響應頭部信息
do {
line = readLine(is, 0, charset);
if (line.startsWith("Content-Length")) {
// 拿到響應體內(nèi)容長度
contentLength = Integer.parseInt(line.split(":")[1].trim());
}
// 如果遇到了一個單獨的回車換行，則表示請求頭結束
} while (!line.equals("\r\n"));
// 讀取出響應體數(shù)據(jù)（就是你要的數(shù)據(jù)）
result = readLine(is, contentLength, charset);
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
if (osw != null) {
try {
osw.close();
} catch (IOException e) {
osw = null;
throw new RuntimeException(e);
} finally {
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
socket = null;
throw new RuntimeException(e);
}
}
}
}
if (is != null) {
try {
is.close();
} catch (IOException e) {
is = null;
throw new RuntimeException(e);
} finally {
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
socket = null;
throw new RuntimeException(e);
}
}
}
}
}
return result;
}
/**
* @Description:使用socket發(fā)送get請求
* @author:liuyc
* @time:2016年5月18日 上午9:27:18
*/
public static String sendSocketGet(String urlParam, Map<String, Object> params, String charset) {
String result = "";
// 構建請求參數(shù)
StringBuffer sbParams = new StringBuffer();
if (params != null && params.size() > 0) {
for (Entry<String, Object> entry : params.entrySet()) {
sbParams.append(entry.getKey());
sbParams.append("=");
sbParams.append(entry.getValue());
sbParams.append("&");
}
}
Socket socket = null;
OutputStreamWriter osw = null;
InputStream is = null;
try {
URL url = new URL(urlParam);
String host = url.getHost();
int port = url.getPort();
if (-1 == port) {
port = 80;
}
String path = url.getPath();
socket = new Socket(host, port);
StringBuffer sb = new StringBuffer();
sb.append("GET " + path + " HTTP/1.1\r\n");
sb.append("Host: " + host + "\r\n");
sb.append("Connection: Keep-Alive\r\n");
sb.append("Content-Type: application/x-www-form-urlencoded; charset=utf-8 \r\n");
sb.append("Content-Length: ").append(sb.toString().getBytes().length).append("\r\n");
// 這里一個回車換行，表示消息頭寫完，不然服務器會繼續(xù)等待
sb.append("\r\n");
if (sbParams != null && sbParams.length() > 0) {
sb.append(sbParams.substring(0, sbParams.length() - 1));
}
osw = new OutputStreamWriter(socket.getOutputStream());
osw.write(sb.toString());
osw.flush();
is = socket.getInputStream();
String line = null;
// 服務器響應體數(shù)據(jù)長度
int contentLength = 0;
// 讀取http響應頭部信息
do {
line = readLine(is, 0, charset);
if (line.startsWith("Content-Length")) {
// 拿到響應體內(nèi)容長度
contentLength = Integer.parseInt(line.split(":")[1].trim());
}
// 如果遇到了一個單獨的回車換行，則表示請求頭結束
} while (!line.equals("\r\n"));
// 讀取出響應體數(shù)據(jù)（就是你要的數(shù)據(jù)）
result = readLine(is, contentLength, charset);
} catch (Exception e) {
throw new RuntimeException(e);
} finally {
if (osw != null) {
try {
osw.close();
} catch (IOException e) {
osw = null;
throw new RuntimeException(e);
} finally {
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
socket = null;
throw new RuntimeException(e);
}
}
}
}
if (is != null) {
try {
is.close();
} catch (IOException e) {
is = null;
throw new RuntimeException(e);
} finally {
if (socket != null) {
try {
socket.close();
} catch (IOException e) {
socket = null;
throw new RuntimeException(e);
}
}
}
}
}
return result;
}
/**
* @Description:讀取一行數(shù)據(jù)，contentLe內(nèi)容長度為0時，讀取響應頭信息，不為0時讀正文
* @time:2016年5月17日 下午6:11:07
*/
private static String readLine(InputStream is, int contentLength, String charset) throws IOException {
List<Byte> lineByte = new ArrayList<Byte>();
byte tempByte;
int cumsum = 0;
if (contentLength != 0) {
do {
tempByte = (byte) is.read();
lineByte.add(Byte.valueOf(tempByte));
cumsum++;
} while (cumsum < contentLength);// cumsum等于contentLength表示已讀完
} else {
do {
tempByte = (byte) is.read();
lineByte.add(Byte.valueOf(tempByte));
} while (tempByte != 10);// 換行符的ascii碼值為10
}
byte[] resutlBytes = new byte[lineByte.size()];
for (int i = 0; i < lineByte.size(); i++) {
resutlBytes[i] = (lineByte.get(i)).byteValue();
}
return new String(resutlBytes, charset);
}
}上面4種分別可發(fā)送get和post請求的方法
- 第1種：HttpURLConnection、
- 第2種：URLConnection、
- 第3種：HttpClient、
- 第4種：Socket，朋友們要注意的是，使用第3種HttpClient時需要依賴于三個jar包，分別是：apache-httpcomponents-httpclient.jar、commons-logging-1.0.4.jar、httpcore-4.1.1.jar。
總結
以上為個人經(jīng)驗，希望能給大家一個參考，也希望大家多多支持腳本之家。
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