關于如何使用java代碼設置代理服務器

在今年年底和外資合作做的一個項目中，由于客戶限制了服務器的外網訪問權限，導致很多涉及到了第三方的API都無法進行訪問，小編給項目組的成員提了一個建議

由于項目組的開發人員公共使用的調用第三方的工具類是基于org.springframework.web.client.RestTemplate進行開發的，所以本節我們就講解RestTemplate中如何使用java代理

1.)當使用的代理服務器不需要密碼驗證時（使用系統參數進行設置代理）'作用域：整個系統'

static {
        String proxyHost = "代理的ip地址或域名";
        String proxyPort = "代理的端口";
        System.getProperties().setProperty("proxySet", "true");

        System.getProperties().setProperty("http.proxyHost", proxyHost);

        System.getProperties().setProperty("http.proxyPort", proxyPort);

        System.getProperties().setProperty("https.proxyHost", proxyHost);

        System.getProperties().setProperty("https.proxyPort", proxyPort);
}

上面這一部分代碼可以放到RestTemplate工具類中，在項目進行啟動的時候就進行全局設置代理，這個方法的作用范圍是整個系統；

2.)當使用的代理服務器不需要密碼驗證時（使用Proxy設置代理）'作用域：指定的請求URL'

public String getData(String url, Map<String, String> param) throws IOException {
        // 設置代理
     SocketAddress socketAddress = new InetSocketAddress("代理的ip地址或域名", 代理的端口);
        Proxy proxy = new Proxy(Proxy.Type.HTTP, socketAddress);
        URL proxyUrl = new URL(url);
        proxyUrl.openConnection(proxy);
        // 請勿輕易改變此提交方式，大部分的情況下，提交方式都是表單提交
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);
        return restTemplate.getForEntity(url, String.class, param).getBody();
}

3.)當使用的代理服務器需要密碼驗證時（使用Proxy設置代理）作用域：指定的URL

由于代理服務器需要密碼驗證，所以我們需要使用java.net.Authenticator.Authenticator.setDefault(Authenticator authenticator)來注冊實現密碼驗證

public class AuthenticatorUtil extends Authenticator {
    // 代理服務器用戶名
    private String user = "";
 //代理服務器密碼
    private String password = "";
    public MyAuthenticator(String user, String password) {
        this.user = user;
        this.password = password;
    }
    protected PasswordAuthentication getPasswordAuthentication() {
        return new PasswordAuthentication(user, password.toCharArray());
    }
}

public String getData(String url, Map<String, String> param) throws IOException {
     // TODO: 2023/1/5  設置代理服務器用戶名和密碼
        Authenticator.setDefault(new AuthenticatorUtil("username", "password"));
        // TODO: 2023/1/5 設置代理服務器的ip地址（域名）和端口
     SocketAddress socketAddress = new InetSocketAddress("代理的ip地址或域名", 代理的端口);
        Proxy proxy = new Proxy(Proxy.Type.HTTP, socketAddress);
        URL proxyUrl = new URL(url);
        proxyUrl.openConnection(proxy);
        // 請勿輕易改變此提交方式，大部分的情況下，提交方式都是表單提交
        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);
        return restTemplate.getForEntity(url, String.class, param).getBody();
}

Java在請求某些不受信任的https網站時會報：'PKIX path building failed'

這個問題也是在做開發的時候遇到的，報錯如下

"I/0 error on PosT reguest for  "https://sfapi-sbox,sf-express.com/std/service ": sunsecurity.validator.ValidatorException: PKIX pathbuilding failed: sun,security,provider.certpathSunCertPathbuilderException: unable to find valid certification path to reguested target; nestedexception is iavax.net.ssl.SSLHandshakeException: sun,security.validator.ValidatorException: PKIX pathbuilding failed: sun,security.provider,certpath,SunCertPathbuilderException: unable to find validcertification-path to requested target"

有些小伙伴看到這個報錯，可能以為是請求不通，其實并不是，而是https://sfapi-sbox,sf-express.com/std/service這個地址不受信任，使用https進行請求的話，所以就有了下面的工具類，用程序重新方法，信任所有的SSL證書

package com.vca.common.utils;

import lombok.SneakyThrows;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.net.ssl.*;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;

/**
 * @Description:信任所有證書工具類
 * @author:chenbing
 * @date 2023/1/4 17:40
 */
public class SslUtil {
    //創建日志記錄工具
    public static final Logger logger = LoggerFactory.getLogger(SslUtil.class);

    private static void trustAllHttpsCertificates() throws Exception {
        TrustManager[] trustAllCerts = new TrustManager[1];
        TrustManager tm = new miTM();
        trustAllCerts[0] = tm;
        SSLContext sc = SSLContext.getInstance("SSL");
        sc.init(null, trustAllCerts, null);
        HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());
    }

    static class miTM implements TrustManager, X509TrustManager {
        public X509Certificate[] getAcceptedIssuers() {
            return null;
        }

        public boolean isServerTrusted(X509Certificate[] certs) {
            return true;
        }

        public boolean isClientTrusted(X509Certificate[] certs) {
            return true;
        }

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

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

    /**
     * @Description:忽略HTTPS請求的SSL證書，必須在openConnection之前調用
     * @author:chenbing
     * @date 2023/1/4 18:00
     */
    @SneakyThrows
    public static void ignoreSsl() {
        HostnameVerifier hv = new HostnameVerifier() {
            public boolean verify(String urlHostName, SSLSession session) {
                logger.info("Warning: URL Host: " + urlHostName + " vs. " + session.getPeerHost());
                return true;
            }
        };
        trustAllHttpsCertificates();
        HttpsURLConnection.setDefaultHostnameVerifier(hv);
    }
}

public String postFormData(String url, MultiValueMap<String, String> map) {
        HttpHeaders headers = new HttpHeaders();
     //再發送請求之前調用ignoreSsl()方法，忽略掉HTTPS請求的SSL證書
        SslUtil.ignoreSsl();
//        headers.setContentType(MediaType.MULTIPART_FORM_DATA);
        HttpEntityString, String>> requests = new HttpEntityString, String>>(map, headers);
        String body = restTemplate.postForEntity(url, requests, String.class).getBody();
        return body;
}