JAVA发送HTTP请求，返回HTTP响应内容，实例及应用

JDK中提供了一些对无状态协议请求（HTTP）的支持，下面我就将我所写的一个小例子（组件）进行描述：

首先让我们先构建一个请求类（HttpRequester）。

该类封装了JAVA实现简单请求的代码，如下：

import java.io.BufferedReader;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.nio.charset.Charset;
import java.util.Map;
import java.util.Vector;

/**
* HTTP请求对象
*
* @author YYmmiinngg
*/
public class HttpRequester {
private String defaultContentEncoding;

public HttpRequester() {
this.defaultContentEncoding = Charset.defaultCharset().name();
}

/**
* 发送GET请求
*
* @param urlString
* URL地址
* @return 响应对象
* @throws IOException
*/
public HttpRespons sendGet(String urlString) throws IOException {
return this.send(urlString, "GET", null, null);
}

/**
* 发送GET请求
*
* @param urlString
* URL地址
* @param params
* 参数集合
* @return 响应对象
* @throws IOException
*/
public HttpRespons sendGet(String urlString, Map<String, String> params)
throws IOException {
return this.send(urlString, "GET", params, null);
}

/**
* 发送GET请求
*
* @param urlString
* URL地址
* @param params
* 参数集合
* @param propertys
* 请求属性
* @return 响应对象
* @throws IOException
*/
public HttpRespons sendGet(String urlString, Map<String, String> params,
Map<String, String> propertys) throws IOException {
return this.send(urlString, "GET", params, propertys);
}

/**
* 发送POST请求
*
* @param urlString
* URL地址
* @return 响应对象
* @throws IOException
*/
public HttpRespons sendPost(String urlString) throws IOException {
return this.send(urlString, "POST", null, null);
}

/**
* 发送POST请求
*
* @param urlString
* URL地址
* @param params
* 参数集合
* @return 响应对象
* @throws IOException
*/
public HttpRespons sendPost(String urlString, Map<String, String> params)
throws IOException {
return this.send(urlString, "POST", params, null);
}

/**
* 发送POST请求
*
* @param urlString
* URL地址
* @param params
* 参数集合
* @param propertys
* 请求属性
* @return 响应对象
* @throws IOException
*/
public HttpRespons sendPost(String urlString, Map<String, String> params,
Map<String, String> propertys) throws IOException {
return this.send(urlString, "POST", params, propertys);
}

/**
* 发送HTTP请求
*
* @param urlString
* @return 响映对象
* @throws IOException
*/
private HttpRespons send(String urlString, String method,
Map<String, String> parameters, Map<String, String> propertys)
throws IOException {
HttpURLConnection urlConnection = null;

if (method.equalsIgnoreCase("GET") && parameters != null) {
StringBuffer param = new StringBuffer();
int i = 0;
for (String key : parameters.keySet()) {
if (i == 0)
param.append("?");
else
param.append("&");
param.append(key).append("=").append(parameters.get(key));
i++;
}
urlString += param;
}
URL url = new URL(urlString);
urlConnection = (HttpURLConnection) url.openConnection();

urlConnection.setRequestMethod(method);
urlConnection.setDoOutput(true);
urlConnection.setDoInput(true);
urlConnection.setUseCaches(false);

if (propertys != null)
for (String key : propertys.keySet()) {
urlConnection.addRequestProperty(key, propertys.get(key));
}

if (method.equalsIgnoreCase("POST") && parameters != null) {
StringBuffer param = new StringBuffer();
for (String key : parameters.keySet()) {
param.append("&");
param.append(key).append("=").append(parameters.get(key));
}
urlConnection.getOutputStream().write(param.toString().getBytes());
urlConnection.getOutputStream().flush();
urlConnection.getOutputStream().close();
}

return this.makeContent(urlString, urlConnection);
}

/**
* 得到响应对象
*
* @param urlConnection
* @return 响应对象
* @throws IOException
*/
private HttpRespons makeContent(String urlString,
HttpURLConnection urlConnection) throws IOException {
HttpRespons httpResponser = new HttpRespons();
try {
InputStream in = urlConnection.getInputStream();
BufferedReader bufferedReader = new BufferedReader(
new InputStreamReader(in));
httpResponser.contentCollection = new Vector<String>();
StringBuffer temp = new StringBuffer();
String line = bufferedReader.readLine();
while (line != null) {
httpResponser.contentCollection.add(line);
temp.append(line).append("/r/n");
line = bufferedReader.readLine();
}
bufferedReader.close();

String ecod = urlConnection.getContentEncoding();
if (ecod == null)
ecod = this.defaultContentEncoding;

httpResponser.urlString = urlString;

httpResponser.defaultPort = urlConnection.getURL().getDefaultPort();
httpResponser.file = urlConnection.getURL().getFile();
httpResponser.host = urlConnection.getURL().getHost();
httpResponser.path = urlConnection.getURL().getPath();
httpResponser.port = urlConnection.getURL().getPort();
httpResponser.protocol = urlConnection.getURL().getProtocol();
httpResponser.query = urlConnection.getURL().getQuery();
httpResponser.ref = urlConnection.getURL().getRef();
httpResponser.userInfo = urlConnection.getURL().getUserInfo();

httpResponser.content = new String(temp.toString().getBytes(), ecod);
httpResponser.contentEncoding = ecod;
httpResponser.code = urlConnection.getResponseCode();
httpResponser.message = urlConnection.getResponseMessage();
httpResponser.contentType = urlConnection.getContentType();
httpResponser.method = urlConnection.getRequestMethod();
httpResponser.connectTimeout = urlConnection.getConnectTimeout();
httpResponser.readTimeout = urlConnection.getReadTimeout();

return httpResponser;
} catch (IOException e) {
throw e;
} finally {
if (urlConnection != null)
urlConnection.disconnect();
}
}

/**
* 默认的响应字符集
*/
public String getDefaultContentEncoding() {
return this.defaultContentEncoding;
}

/**
* 设置默认的响应字符集
*/
public void setDefaultContentEncoding(String defaultContentEncoding) {
this.defaultContentEncoding = defaultContentEncoding;
}
}

其次我们来看看响应对象（HttpRespons）。
响应对象其实只是一个数据BEAN，由此来封装请求响应的结果数据，如下：

import java.util.Vector;

/**
* 响应对象
*/
public class HttpRespons {

String urlString;

int defaultPort;

String file;

String host;

String path;

int port;

String protocol;

String query;

String ref;

String userInfo;

String contentEncoding;

String content;

String contentType;

int code;

String message;

String method;

int connectTimeout;

int readTimeout;

Vector<String> contentCollection;

public String getContent() {
return content;
}

public String getContentType() {
return contentType;
}

public int getCode() {
return code;
}

public String getMessage() {
return message;
}

public Vector<String> getContentCollection() {
return contentCollection;
}

public String getContentEncoding() {
return contentEncoding;
}

public String getMethod() {
return method;
}

public int getConnectTimeout() {
return connectTimeout;
}

public int getReadTimeout() {
return readTimeout;
}

public String getUrlString() {
return urlString;
}

public int getDefaultPort() {
return defaultPort;
}

public String getFile() {
return file;
}

public String getHost() {
return host;
}

public String getPath() {
return path;
}

public int getPort() {
return port;
}

public String getProtocol() {
return protocol;
}

public String getQuery() {
return query;
}

public String getRef() {
return ref;
}

public String getUserInfo() {
return userInfo;
}

}

最后，让我们写一个应用类，测试以上代码是否正确

import com.yao.http.HttpRequester;
import com.yao.http.HttpRespons;

public class Test {
public static void main(String[] args) {
try {
HttpRequester request = new HttpRequester();
HttpRespons hr = request.sendGet("http://www.csdn.net");

System.out.println(hr.getUrlString());
System.out.println(hr.getProtocol());
System.out.println(hr.getHost());
System.out.println(hr.getPort());
System.out.println(hr.getContentEncoding());
System.out.println(hr.getMethod());

System.out.println(hr.getContent());

} catch (Exception e) {
e.printStackTrace();
}
}
}