一、背景

    博主在java后端调用气象数据接口时找到个合适的免费接口，是京东智联云旗下的，接口文档地址如下 https://wx.jdcloud.com/market/datas/26/11065 ，但是在调用的时候报错sun.security.validator.ValidatorException: PKIX path building failed。网上找了很多，说法都比较一致，那就是需要调用网站的证书安装在本地，那么有没有不需要证书的办法呢？

二、实战！

    1.service实现层直接返回接口的json数据，转为String接收代码如下：

/**
	 * 通过接口获取天气数据
	 * 
	 * @param id
	 * @return
	 */
	public String getEnvironmentWeatherDataByInternet() {
		String path = SOJSON_WEATHER_URL_START + this.cityid + SOJSON_WEATHER_URL_END;
		return HttpsUrlValidator.retrieveResponseFromServer(path); 
	}

    2.关键的HttpsUrlValidator类代码如下：

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;

import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.HttpsURLConnection;
import javax.net.ssl.SSLSession;

/**
 * https接口调用忽略证书工具类
 * @author frr
 * @date 2020-04-09
 */
public class HttpsUrlValidator {
	
	static HostnameVerifier hv = new HostnameVerifier() {
        public boolean verify(String urlHostName, SSLSession session) {
            System.out.println("Warning: URL Host: " + urlHostName + " vs. "
                               + session.getPeerHost());
            return true;
        }
    };

    public final static String retrieveResponseFromServer(final String url) {
        HttpURLConnection connection = null;
        
        try {
            URL validationUrl = new URL(url);
            trustAllHttpsCertificates();
            HttpsURLConnection.setDefaultHostnameVerifier(hv);

            connection = (HttpURLConnection) validationUrl.openConnection();
            final BufferedReader in = new BufferedReader(new InputStreamReader(
                    connection.getInputStream()));

            String line;
            final StringBuffer stringBuffer = new StringBuffer(255);

            synchronized (stringBuffer) {
                while ((line = in.readLine()) != null) {
                    stringBuffer.append(line);
                    stringBuffer.append("\n");
                }
                return stringBuffer.toString();
            }

        } catch (final IOException e) {
            System.out.println(e.getMessage());
            return null;
        } catch (final Exception e1){
            System.out.println(e1.getMessage());
            return null;
        }finally {
            if (connection != null) {
                connection.disconnect();
            }
        }
    }
    
    public static void trustAllHttpsCertificates() throws Exception {
        javax.net.ssl.TrustManager[] trustAllCerts = new javax.net.ssl.TrustManager[1];
        javax.net.ssl.TrustManager tm = new miTM();
        trustAllCerts[0] = tm;
        javax.net.ssl.SSLContext sc = javax.net.ssl.SSLContext
                .getInstance("SSL");
        sc.init(null, trustAllCerts, null);
        javax.net.ssl.HttpsURLConnection.setDefaultSSLSocketFactory(sc
                .getSocketFactory());
    }

    static class miTM implements javax.net.ssl.TrustManager,
            javax.net.ssl.X509TrustManager {
        public java.security.cert.X509Certificate[] getAcceptedIssuers() {
            return null;
        }

        public boolean isServerTrusted(
                java.security.cert.X509Certificate[] certs) {
            return true;
        }

        public boolean isClientTrusted(
                java.security.cert.X509Certificate[] certs) {
            return true;
        }

        public void checkServerTrusted(
                java.security.cert.X509Certificate[] certs, String authType)
                throws java.security.cert.CertificateException {
            return;
        }

        public void checkClientTrusted(
                java.security.cert.X509Certificate[] certs, String authType)
                throws java.security.cert.CertificateException {
            return;
        }
    }
}

    运行结果，完美完成接口的调用，解决了java后台请求https类型的接口需要安装证书的问题。