Java发起请求get/post工具类

 注：在使用Get请求时，如果不将空格转换则会报Http505错误

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;

import org.apache.http.*;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;



public class HttpClientUtils {

	 
	/**
	 * 发送post请求
	 * @param url
	 * @param json
	 * @return
	 */
	public static String post(String url, String json){
		DefaultHttpClient client = new DefaultHttpClient();
		HttpPost post = new HttpPost(url);
		
		//设置编码
		post.addHeader("Content-Type", "application/json;charset=utf-8");

		String result=null;
		try {
			StringEntity s = new StringEntity(json,"utf-8");
			
			s.setContentEncoding("UTF-8");//
			s.setContentType("application/json");//发送json数据需要设置contentType
			post.setEntity(s);
			HttpResponse res = client.execute(post);
			if(res.getStatusLine().getStatusCode() == HttpStatus.SC_OK){
				HttpEntity entity = res.getEntity();
				 result = EntityUtils.toString(res.getEntity());// 返回json格式：
//				response = JSONObject.fromObject(result);
			}
		} catch (Exception e) {
			throw new RuntimeException(e);
		}
		return result;
	}

    /**
     *
     * @param url 请求地址
     * @param param 如果请求地址中已经拼接了参数，就不要再传参数
     * @return
     */
	public static String get(String url, String param) {

        String result = "";
        BufferedReader in = null;
        try {
            String urlNameString=url;
            if(param!=null){
                urlNameString= url + "?" + param;
            }
            //判断是否有空格，并替换为%
            if(urlNameString.contains(" ")){
                urlNameString.replace(" ","%");
            }
            URL realUrl = new URL(urlNameString);
            // 打开和URL之间的连接
            URLConnection connection = realUrl.openConnection();
            // 设置通用的请求属性
            connection.setRequestProperty("accept","*/*");
            connection.setRequestProperty("connection","Keep-Alive");
            connection.setRequestProperty("user-agent","Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
            // 建立实际的连接
            connection.connect();
            // 获取所有响应头字段y
            in = new BufferedReader(new InputStreamReader(
                    connection.getInputStream()));
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            //发送GET请求出现异常!
            e.printStackTrace();
        }
        // 使用finally块来关闭输入流
        finally {
            try {
                if (in != null) {
                    in.close();
                }
            } catch (Exception e2) {
                e2.printStackTrace();
            }
        }
        return result;
    }

}