java中的常见几种发送http请求实例
作者：北极熊不在北极
在Java编程中,发送HTTP请求是一个常见需求,常用的方法有四种：HttpURLConnection、URLConnection、HttpClient以及Socket,其中,使用HttpClient方式时,需要添加额外的库支持
java常见几种发送http请求实例
<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:发送http请求帮助类
* @author:liuyc
* @time:2016年5月17日 下午3:25:32
*/
public class HttpClientHelper {
/**
* @Description:使用HttpURLConnection发送post请求
* @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;
// 构建请求参数
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;
// 发送请求
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();
}
// 读取返回内容
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发送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;
// 构建请求参数
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);
// 打开和URL之间的连接
con = realUrl.openConnection();
// 设置通用的请求属性
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)");
// 发送POST请求必须设置如下两行
con.setDoOutput(true);
con.setDoInput(true);
// 获取URLConnection对象对应的输出流
osw = new OutputStreamWriter(con.getOutputStream(), charset);
if (sbParams != null && sbParams.length() > 0) {
// 发送请求参数
osw.write(sbParams.substring(0, sbParams.length() - 1));
// flush输出流的缓冲
osw.flush();
}
// 定义BufferedReader输入流来读取URL的响应
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:发送get请求保存下载文件
* @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) {
// 构建请求参数
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发送get请求
* @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;
// 构建请求参数
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发送get请求
* @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;
// 构建请求参数
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();
// 设置请求属性
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)");
// 建立连接
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发送post请求
* @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);
// 构建请求参数
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);
// 读取服务器响应数据
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发送get请求
* @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;
// 构建请求参数
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);
// 读取服务器响应数据
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发送post请求
* @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 = "";
// 构建请求参数
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");
// 这里一个回车换行，表示消息头写完，不然服务器会继续等待
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;
// 服务器响应体数据长度
int contentLength = 0;
// 读取http响应头部信息
do {
line = readLine(is, 0, charset);
if (line.startsWith("Content-Length")) {
// 拿到响应体内容长度
contentLength = Integer.parseInt(line.split(":")[1].trim());
}
// 如果遇到了一个单独的回车换行，则表示请求头结束
} while (!line.equals("\r\n"));
// 读取出响应体数据（就是你要的数据）
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发送get请求
* @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 = "";
// 构建请求参数
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");
// 这里一个回车换行，表示消息头写完，不然服务器会继续等待
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;
// 服务器响应体数据长度
int contentLength = 0;
// 读取http响应头部信息
do {
line = readLine(is, 0, charset);
if (line.startsWith("Content-Length")) {
// 拿到响应体内容长度
contentLength = Integer.parseInt(line.split(":")[1].trim());
}
// 如果遇到了一个单独的回车换行，则表示请求头结束
} while (!line.equals("\r\n"));
// 读取出响应体数据（就是你要的数据）
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:读取一行数据，contentLe内容长度为0时，读取响应头信息，不为0时读正文
* @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表示已读完
} else {
do {
tempByte = (byte) is.read();
lineByte.add(Byte.valueOf(tempByte));
} while (tempByte != 10);// 换行符的ascii码值为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种分别可发送get和post请求的方法
- 第1种：HttpURLConnection、
- 第2种：URLConnection、
- 第3种：HttpClient、
- 第4种：Socket，朋友们要注意的是，使用第3种HttpClient时需要依赖于三个jar包，分别是：apache-httpcomponents-httpclient.jar、commons-logging-1.0.4.jar、httpcore-4.1.1.jar。
总结
以上为个人经验，希望能给大家一个参考，也希望大家多多支持脚本之家。