关于JAVA发送Https请求（HttpsURLConnection和HttpURLConnection）

深碍√TFBOYSˉ_ 2021-06-11 15:12 457阅读 0赞

https协议对于开发者而言其实只是多了一步证书验证的过程。这个证书正常情况下被jdk/jre/security/cacerts所管理。里面证书包含两种情况：

1、机构所颁发的被认证的证书，这种证书的网站在浏览器访问时https头显示为绿色如百度

2、个人所设定的证书，这种证书的网站在浏览器里https头显示为红色×，且需要点击信任该网站才能继续访问。而点击信任这一步的操作就是我们在java代码访问https网站时区别于http请求需要做的事情。

![76503601][]所以JAVA发送Https请求有两种情况，三种解决办法：

第一种情况：Https网站的证书为机构所颁发的被认证的证书，这种情况下和http请求一模一样，无需做任何改变，用HttpsURLConnection或者HttpURLConnection都可以

public static void main(String[] args) throws Exception{
            URL serverUrl = new URL("https://xxxx");
            HttpURLConnection conn = (HttpURLConnection) serverUrl.openConnection();
            conn.setRequestMethod("GET");
            conn.setRequestProperty("Content-type", "application/json");
            //必须设置false，否则会自动redirect到重定向后的地址
            conn.setInstanceFollowRedirects(false);
            conn.connect();
            String result = getReturn(conn);
        }
     
        /*请求url获取返回的内容*/
        public static String getReturn(HttpURLConnection connection) throws IOException{
            StringBuffer buffer = new StringBuffer();
            //将返回的输入流转换成字符串
            try(InputStream inputStream = connection.getInputStream();
                InputStreamReader inputStreamReader = new InputStreamReader(inputStream, ConstantInfo.CHARSET);
                BufferedReader bufferedReader = new BufferedReader(inputStreamReader);){
                String str = null;
                while ((str = bufferedReader.readLine()) != null) {
                    buffer.append(str);
                }
                String result = buffer.toString();
                return result;
            }
    }

第二种情况：个人所设定的证书，这种证书默认不被信任，需要我们自己选择信任，信任的办法有两种：

A、将证书导入java的运行环境中

*  从该网站下载或者从网站开发者出获取证书cacert.crt
 *  运行命令将证书导入java运行环境：keytool -import -keystore %JAVA\_HOME%\\jre\\lib\\security\\cacerts -file cacert.crt -alias xxx
 *  完成。java代码中发送https的请求和http一样，同第一种情况。

B、忽略证书验证过程，忽略之后任何Https协议网站皆能正常访问，同第一种情况

import java.security.cert.CertificateException;
    import java.security.cert.X509Certificate;
    import javax.net.ssl.X509TrustManager;
    public class MyX509TrustManager implements X509TrustManager {
     
        @Override
        public void checkClientTrusted(X509Certificate certificates[],String authType) throws CertificateException {
        }
     
        @Override
        public void checkServerTrusted(X509Certificate[] ax509certificate,String s) throws CertificateException {
        }
     
        @Override
        public X509Certificate[] getAcceptedIssuers() {
            // TODO Auto-generated method stub
            return null;
        }
    }

C、java代码中加载证书，必须使用HttpsURLConnection方式

public static void main(String[] args) throws Exception{  
            SSLContext sslcontext = SSLContext.getInstance("SSL","SunJSSE");  
            sslcontext.init(null, new TrustManager[]{new MyX509TrustManager()}, new java.security.SecureRandom());  
            URL serverUrl = new URL("https://xxxx");  
            HttpsURLConnection conn = (HttpsURLConnection) serverUrl.openConnection();  
            conn.setSSLSocketFactory(sslcontext.getSocketFactory());  
            conn.setRequestMethod("GET");  
            conn.setRequestProperty("Content-type", "application/json");  
            //必须设置false，否则会自动redirect到重定向后的地址  
            conn.setInstanceFollowRedirects(false);  
            conn.connect();  
            String result = getReturn(conn);  
        }  
      
        /*请求url获取返回的内容*/  
        public static String getReturn(HttpsURLConnection connection) throws IOException{  
            StringBuffer buffer = new StringBuffer();  
            //将返回的输入流转换成字符串  
            try(InputStream inputStream = connection.getInputStream();  
                InputStreamReader inputStreamReader = new InputStreamReader(inputStream, ConstantInfo.CHARSET);  
                BufferedReader bufferedReader = new BufferedReader(inputStreamReader);){  
                String str = null;  
                while ((str = bufferedReader.readLine()) != null) {  
                    buffer.append(str);  
                }  
                String result = buffer.toString();  
                return result;  
            }  
    }

[76503601]: /images/20210606/17b8d2e4df434de89a08a9e3d80f85d0.png