• java中模拟http(https)请求的工具类


    在java中,特别是java web中,我们经常需要碰到的一个场景是我们需要从服务端去发送http请求,获取到数据,而不是直接从浏览器输入请求网址获得相应。比如我们想访问微信接口,获取其返回信息。

    在这里需要用到java的HttpURLConnection类,此类可以模拟http请求,获取到的响应以输入流的形式被程序所取到。现将相关方法整理为工具类。

    package com.m_gecko.util;
    
    import java.io.BufferedReader;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.InputStreamReader;
    import java.io.OutputStream;
    import java.io.OutputStreamWriter;
    import java.io.PrintWriter;
    import java.io.UnsupportedEncodingException;
    import java.net.ConnectException;
    import java.net.HttpURLConnection;
    import java.net.MalformedURLException;
    import java.net.URL;
    import java.net.URLEncoder;
    import java.util.List;
    import java.util.Map;
    
    import javax.net.ssl.HttpsURLConnection;
    import javax.net.ssl.SSLContext;
    import javax.net.ssl.SSLSocketFactory;
    import javax.net.ssl.TrustManager;
    
    import org.apache.commons.io.IOUtils;
    
    public class HttpUtil {
        /**
         * 模拟http的get请求,获取响应(输入流),然后把输入流转为
         * 
         * @param url
         * @return
         */
        public static String httpGet(String url) {
            HttpURLConnection connection = null;
            InputStream response = null;
            try {
                connection = (HttpURLConnection) new URL(url).openConnection();
                connection.setConnectTimeout(10000);
                connection.setReadTimeout(10000);
                response = connection.getInputStream();
                if (response != null) {
                    String nextLine = IOUtils.toString(response, "utf-8");
                    return nextLine;
                }
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                if (response != null)
                    try {
                        response.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                if (connection != null) {
                    connection.disconnect();
                    connection = null;
                }
            }
            return null;
        }
    
        /**
         * 模拟http的post请求,类似上面
         * 
         * @param url
         * @return
         */
        public static String httpPost(String url) {
            HttpURLConnection connection = null;
            InputStream response = null;
            try {
                connection = (HttpURLConnection) new URL(url).openConnection();
                connection.setConnectTimeout(30000);
                connection.setReadTimeout(30000);
                // 发送POST请求必须设置如下两行
                connection.setDoOutput(true);
                connection.setDoInput(true);
                response = connection.getInputStream();
                if (response != null) {
                    String nextLine = IOUtils.toString(response, "utf-8");
                    return nextLine;
                }
            } catch (MalformedURLException e) {
                e.printStackTrace();
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                if (response != null)
                    try {
                        response.close();
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                if (connection != null) {
                    connection.disconnect();
                    connection = null;
                }
            }
            return null;
        }
    
        /**
         * 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
                HttpURLConnection connection = (HttpURLConnection) 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(), "utf-8"));
                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。
         * @return 所代表远程资源的响应结果
         */
        public static String sendPost(String url, String param) {
            PrintWriter out = null;
            BufferedReader in = null;
            String result = "";
            try {
                URL realUrl = new URL(url);
                // 打开和URL之间的连接
                HttpURLConnection conn = (HttpURLConnection) 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(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(), "utf-8"));
                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;
        }
    
        /**
         * 向指定 URL 发送POST方法的请求
         * 
         * @param url
         *            发送请求的 URL
         * @param params
         *            请求的参数集合
         * @return 远程资源的响应结果
         */
        public static String sendPost(String url, Map<String, String> params) {
            OutputStreamWriter out = null;
            BufferedReader in = null;
            StringBuilder result = new StringBuilder();
            try {
                URL realUrl = new URL(url);
                HttpURLConnection conn = (HttpURLConnection) realUrl
                        .openConnection();
                // 发送POST请求必须设置如下两行
                conn.setDoOutput(true);
                conn.setDoInput(true);
                // POST方法
                conn.setRequestMethod("POST");
                // 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
                if (params != null) {
                    StringBuilder param = new StringBuilder();
                    for (Map.Entry<String, String> entry : params.entrySet()) {
                        if (param.length() > 0) {
                            param.append("&");
                        }
                        param.append(entry.getKey());
                        param.append("=");
                        param.append(entry.getValue());
                        // System.out.println(entry.getKey()+":"+entry.getValue());
                    }
                    System.out.println("param:" + param.toString());
                    out.write(param.toString());
                }
                // 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(), "UTF-8"));
                String line;
                while ((line = in.readLine()) != null) {
                    result.append(line);
                }
            } catch (Exception 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.toString();
        }
    
        /**
         * url编码
         * 
         * @param str
         * @param charset
         * @return
         * @throws UnsupportedEncodingException
         */
        public static String urlEncoder(String str, String charset)
                throws UnsupportedEncodingException {
            if (str == null) {
                str = "";
            }
            String result = URLEncoder.encode(str, charset);
            return result;
        }
    
        /**
         * 发送https请求
         * 
         * @param requestUrl
         *            请求地址
         * @param requestMethod
         *            请求方式(GET、POST)
         * @param outputStr
         *            提交的数据
         * @return 返回微信服务器响应的信息
         */
        public static String httpsRequest(String requestUrl, String requestMethod,
                String outputStr) {
            try {
                // 创建SSLContext对象,并使用我们指定的信任管理器初始化
                TrustManager[] tm = { new MyX509TrustManager() };
                SSLContext sslContext = SSLContext.getInstance("SSL", "SunJSSE");
                sslContext.init(null, tm, new java.security.SecureRandom());
                // 从上述SSLContext对象中得到SSLSocketFactory对象
                SSLSocketFactory ssf = sslContext.getSocketFactory();
                URL url = new URL(requestUrl);
                HttpsURLConnection conn = (HttpsURLConnection) url.openConnection();
                conn.setSSLSocketFactory(ssf);
                conn.setDoOutput(true);
                conn.setDoInput(true);
                conn.setUseCaches(false);
                // 设置请求方式(GET/POST)
                conn.setRequestMethod(requestMethod);
                conn.setRequestProperty("content-type",
                        "application/x-www-form-urlencoded");
                // 当outputStr不为null时向输出流写数据
                if (null != outputStr) {
                    OutputStream outputStream = conn.getOutputStream();
                    // 注意编码格式
                    outputStream.write(outputStr.getBytes("UTF-8"));
                    outputStream.close();
                }
                // 从输入流读取返回内容
                InputStream inputStream = conn.getInputStream();
                InputStreamReader inputStreamReader = new InputStreamReader(
                        inputStream, "utf-8");
                BufferedReader bufferedReader = new BufferedReader(
                        inputStreamReader);
                String str = null;
                StringBuffer buffer = new StringBuffer();
                while ((str = bufferedReader.readLine()) != null) {
                    buffer.append(str);
                }
                // 释放资源
                bufferedReader.close();
                inputStreamReader.close();
                inputStream.close();
                inputStream = null;
                conn.disconnect();
                return buffer.toString();
            } catch (ConnectException ce) {
                ce.printStackTrace();
            } catch (Exception e) {
                e.printStackTrace();
            }
            return null;
        }
    }

    其中https请求所需要的信任管理器实现了X509TrustManager接口。

    package com.m_gecko.util;
    
    import java.security.cert.CertificateException;
    import java.security.cert.X509Certificate;
    import javax.net.ssl.X509TrustManager;
    
    /**
     * 信任管理器
     * @author xdx
     */
    public class MyX509TrustManager implements X509TrustManager {
    
        // 检查客户端证书
        public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
        }
    
        // 检查服务器端证书
        public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {
        }
    
        // 返回受信任的X509证书数组
        public X509Certificate[] getAcceptedIssuers() {
            return null;
        }
    }
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  • 原文地址:https://www.cnblogs.com/roy-blog/p/7206877.html
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