Java发送http get/post请求，调用接口/方法

由于项目中要用，所以找了一些资料，整理下来。

GitHub地址: https://github.com/iamyong    转自：http://blog.csdn.net/capmiachael/article/details/51833531

例1：使用 HttpClient （commons-httpclient-3.0.jar 

import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;

import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.methods.InputStreamRequestEntity;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.methods.RequestEntity;

public class HttpTool {

    /**
     * 发送post请求
     * 
     * @param params
     *            参数
     * @param requestUrl
     *            请求地址
     * @param authorization
     *            授权书
     * @return 返回结果
     * @throws IOException
     */
    public static String sendPost(String params, String requestUrl,
            String authorization) throws IOException {

        byte[] requestBytes = params.getBytes("utf-8"); // 将参数转为二进制流
        HttpClient httpClient = new HttpClient();// 客户端实例化
        PostMethod postMethod = new PostMethod(requestUrl);
        //设置请求头Authorization
        postMethod.setRequestHeader("Authorization", "Basic " + authorization);
        // 设置请求头  Content-Type
        postMethod.setRequestHeader("Content-Type", "application/json");
        InputStream inputStream = new ByteArrayInputStream(requestBytes, 0,
                requestBytes.length);
        RequestEntity requestEntity = new InputStreamRequestEntity(inputStream,
                requestBytes.length, "application/json; charset=utf-8"); // 请求体
        postMethod.setRequestEntity(requestEntity);
        httpClient.executeMethod(postMethod);// 执行请求
        InputStream soapResponseStream = postMethod.getResponseBodyAsStream();// 获取返回的流
        byte[] datas = null;
        try {
            datas = readInputStream(soapResponseStream);// 从输入流中读取数据
        } catch (Exception e) {
            e.printStackTrace();
        }
        String result = new String(datas, "UTF-8");// 将二进制流转为String
        // 打印返回结果
        // System.out.println(result);

        return result;

    }

    /**
     * 从输入流中读取数据
     * 
     * @param inStream
     * @return
     * @throws Exception
     */
    public static byte[] readInputStream(InputStream inStream) throws Exception {
        ByteArrayOutputStream outStream = new ByteArrayOutputStream();
        byte[] buffer = new byte[1024];
        int len = 0;
        while ((len = inStream.read(buffer)) != -1) {
            outStream.write(buffer, 0, len);
        }
        byte[] data = outStream.toByteArray();
        outStream.close();
        inStream.close();
        return data;
    }
}

例2：

import java.io.BufferedReader;  
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.InetSocketAddress;
import java.net.Proxy;
import java.net.URL; 
import java.net.URLConnection;
import java.util.List;
import java.util.Map;

/** 
 * Http请求工具类 
 */
public class HttpRequestUtil {
    static boolean proxySet = false;
    static String proxyHost = "127.0.0.1";
    static int proxyPort = 8087;
    /** 
     * 编码 
     * @param source 
     * @return 
     */ 
    public static String urlEncode(String source,String encode) {  
        String result = source;  
        try {  
            result = java.net.URLEncoder.encode(source,encode);  
        } catch (UnsupportedEncodingException e) {  
            e.printStackTrace();  
            return "0";  
        }  
        return result;  
    }
    public static String urlEncodeGBK(String source) {  
        String result = source;  
        try {  
            result = java.net.URLEncoder.encode(source,"GBK");  
        } catch (UnsupportedEncodingException e) {  
            e.printStackTrace();  
            return "0";  
        }  
        return result;  
    }
    /** 
     * 发起http请求获取返回结果 
     * @param req_url 请求地址 
     * @return 
     */ 
    public static String httpRequest(String req_url) {
        StringBuffer buffer = new StringBuffer();  
        try {  
            URL url = new URL(req_url);  
            HttpURLConnection httpUrlConn = (HttpURLConnection) url.openConnection();  

            httpUrlConn.setDoOutput(false);  
            httpUrlConn.setDoInput(true);  
            httpUrlConn.setUseCaches(false);  

            httpUrlConn.setRequestMethod("GET");  
            httpUrlConn.connect();  

            // 将返回的输入流转换成字符串  
            InputStream inputStream = httpUrlConn.getInputStream();  
            InputStreamReader inputStreamReader = new InputStreamReader(inputStream, "utf-8");  
            BufferedReader bufferedReader = new BufferedReader(inputStreamReader);  

            String str = null;  
            while ((str = bufferedReader.readLine()) != null) {  
                buffer.append(str);  
            }  
            bufferedReader.close();  
            inputStreamReader.close();  
            // 释放资源  
            inputStream.close();  
            inputStream = null;  
            httpUrlConn.disconnect();  

        } catch (Exception e) {  
            System.out.println(e.getStackTrace());  
        }  
        return buffer.toString();  
    }  

    /** 
     * 发送http请求取得返回的输入流 
     * @param requestUrl 请求地址 
     * @return InputStream 
     */ 
    public static InputStream httpRequestIO(String requestUrl) {  
        InputStream inputStream = null;  
        try {  
            URL url = new URL(requestUrl);  
            HttpURLConnection httpUrlConn = (HttpURLConnection) url.openConnection();  
            httpUrlConn.setDoInput(true);  
            httpUrlConn.setRequestMethod("GET");  
            httpUrlConn.connect();  
            // 获得返回的输入流  
            inputStream = httpUrlConn.getInputStream();  
        } catch (Exception e) {  
            e.printStackTrace();  
        }  
        return inputStream;  
    }


    /**
     * 向指定URL发送GET方法的请求
     * 
     * @param url
     *            发送请求的URL
     * @param param
     *            请求参数，请求参数应该是 name1=value1&name2=value2 的形式。
     * @return URL 所代表远程资源的响应结果
     */
    public static String sendGet(String url, String param) {
        String result = "";
        BufferedReader in = null;
        try {
            String urlNameString = url + "?" + param;
            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
            Map<String, List<String>> map = connection.getHeaderFields();
            // 遍历所有的响应头字段
            for (String key : map.keySet()) {
                System.out.println(key + "--->" + map.get(key));
            }
            // 定义 BufferedReader输入流来读取URL的响应
            in = new BufferedReader(new InputStreamReader(
                    connection.getInputStream()));
            String line;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            System.out.println("发送GET请求出现异常！" + e);
            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;
    }

    /**
     * 向指定 URL 发送POST方法的请求
     * 
     * @param url
     *            发送请求的 URL
     * @param param
     *            请求参数，请求参数应该是 name1=value1&name2=value2 的形式。
     * @param isproxy
     *               是否使用代理模式
     * @return 所代表远程资源的响应结果
     */
    public static String sendPost(String url, String param,boolean isproxy) {
        OutputStreamWriter out = null;
        BufferedReader in = null;
        String result = "";
        try {
            URL realUrl = new URL(url);
            HttpURLConnection conn = null;
            if(isproxy){//使用代理模式
                @SuppressWarnings("static-access")
                Proxy proxy = new Proxy(Proxy.Type.DIRECT.HTTP, new InetSocketAddress(proxyHost, proxyPort));
                conn = (HttpURLConnection) realUrl.openConnection(proxy);
            }else{
                conn = (HttpURLConnection) realUrl.openConnection();
            }
            // 打开和URL之间的连接

            // 发送POST请求必须设置如下两行
            conn.setDoOutput(true);
            conn.setDoInput(true);
            conn.setRequestMethod("POST");    // POST方法


            // 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)");
            conn.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");

            conn.connect();

            // 获取URLConnection对象对应的输出流
            out = new OutputStreamWriter(conn.getOutputStream(), "UTF-8");
            // 发送请求参数
            out.write(param);
            // 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;
            while ((line = in.readLine()) != null) {
                result += line;
            }
        } catch (Exception e) {
            System.out.println("发送 POST 请求出现异常！"+e);
            e.printStackTrace();
        }
        //使用finally块来关闭输出流、输入流
        finally{
            try{
                if(out!=null){
                    out.close();
                }
                if(in!=null){
                    in.close();
                }
            }
            catch(IOException ex){
                ex.printStackTrace();
            }
        }
        return result;
    }    

    public static void main(String[] args) {
        //demo:代理访问
        String url = "http://api.adf.ly/api.php";
        String para = "key=youkeyid&youuid=uid&advert_type=int&domain=adf.ly&url=http://somewebsite.com";

        String sr=HttpRequestUtil.sendPost(url,para,true);
        System.out.println(sr);
    }

}

例3

/**
     * 发送Http post请求
     * 
     * @param xmlInfo
     *            json转化成的字符串
     * @param URL
     *            请求url
     * @return 返回信息
     */
    public static String doHttpPost(String xmlInfo, String URL) {
        System.out.println("发起的数据:" + xmlInfo);
        byte[] xmlData = xmlInfo.getBytes();
        InputStream instr = null;
        java.io.ByteArrayOutputStream out = null;
        try {
            URL url = new URL(URL);
            URLConnection urlCon = url.openConnection();
            urlCon.setDoOutput(true);
            urlCon.setDoInput(true);
            urlCon.setUseCaches(false);
            urlCon.setRequestProperty("content-Type", "application/json");
            urlCon.setRequestProperty("charset", "utf-8");
            urlCon.setRequestProperty("Content-length",
                    String.valueOf(xmlData.length));
            System.out.println(String.valueOf(xmlData.length));
            DataOutputStream printout = new DataOutputStream(
                    urlCon.getOutputStream());
            printout.write(xmlData);
            printout.flush();
            printout.close();
            instr = urlCon.getInputStream();
            byte[] bis = IOUtils.toByteArray(instr);
            String ResponseString = new String(bis, "UTF-8");
            if ((ResponseString == null) || ("".equals(ResponseString.trim()))) {
                System.out.println("返回空");
            }
            System.out.println("返回数据为:" + ResponseString);
            return ResponseString;

        } catch (Exception e) {
            e.printStackTrace();
            return "0";
        } finally {
            try {
                out.close();
                instr.close();

            } catch (Exception ex) {
                return "0";
            }
        }
    }