Java发起Post请求的两种方式

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.URL;
import java.net.URLConnection;
import java.util.Map;

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.HttpMethod;
import org.apache.commons.httpclient.HttpStatus;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.params.HttpMethodParams;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class HttpUtils {
private static final Logger logger = LoggerFactory
.getLogger(HttpUtils.class);

public static String doPost(String url, Map<String, String> params) {
String response = null;
HttpClient client = new HttpClient();
HttpMethod method = new PostMethod(url);

// 设置Http Post数据
if (params != null) {
HttpMethodParams p = new HttpMethodParams();
for (Map.Entry<String, String> entry : params.entrySet()) {
p.setParameter(entry.getKey(), entry.getValue());
}
method.setParams(p);
}
method.setRequestHeader("accept", "*/*");
method.setRequestHeader("connection", "Keep-Alive");
method.setRequestHeader("user-agent",
"Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
try {
client.executeMethod(method);
if (method.getStatusCode() == HttpStatus.SC_OK) {
response = method.getResponseBodyAsString();
} else {
logger.error("statusCode:{}", method.getStatusCode());
}
} catch (IOException e) {
logger.error("{}", e);
} finally {
method.releaseConnection();
}

return response;
}

/**
* 向指定 URL 发送POST方法的请求
*
* @param url
*            发送请求的 URL
* @param params
*            请求参数，请求参数应该是 name1=value1&name2=value2 的形式。
* @return 所代表远程资源的响应结果
*/
public static String doPost(String url, String params) {
PrintWriter out = null;
BufferedReader in = null;
StringBuilder result = new StringBuilder();
try {
URL realUrl = new URL(url);
// 打开和URL之间的连接
URLConnection conn = realUrl.openConnection();
// 设置通用的请求属性
conn.setRequestProperty("accept", "*/*");
conn.setRequestProperty("connection", "Keep-Alive");
conn.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
conn.setDoOutput(true);
conn.setDoInput(true);
// 获取URLConnection对象对应的输出流
out = new PrintWriter(conn.getOutputStream());
// 发送请求参数
out.print(params);
// flush输出流的缓冲
out.flush();
// 定义BufferedReader输入流来读取URL的响应
in = new BufferedReader(
new InputStreamReader(conn.getInputStream()));
String line = null;
while ((line = in.readLine()) != null) {
result.append(line);
}
} catch (Exception e) {
logger.error("{}", e);
} finally {
// 使用finally块来关闭输出流、输入流
if (out != null) {
out.close();
}
try {
if (in != null) {
in.close();
}
} catch (IOException e) {
logger.error("{}", e);
}
}
return result.toString();
}

public static void main(String[] args) {

}
}