https请求报错unable to find valid certification path to requested target解决

��       在Java项目中请求HTTPS时，可能会遇到 "unable to find valid certification path to requested target" 错误。这个错误通常是由于SSL证书问题引起的。要解决此问题，可以尝试以下方法

1.忽略SSL验证

        OkHttpClient封装请求

public static OkHttpClient getUnsafeOkHttpClient() {        try {            // 创建一个信任所有证书的TrustManager            final TrustManager[] trustAllCerts = new TrustManager[]{                    new X509TrustManager() {                        @Override                        public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {                        }                        @Override                        public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {                        }                        @Override                        public X509Certificate[] getAcceptedIssuers() {                            return new X509Certificate[0];                        }                    }            };            // 创建一个不验证证书的 SSLContext，并使用上面的TrustManager初始化            SSLContext sslContext = SSLContext.getInstance("SSL");            sslContext.init(null, trustAllCerts, new java.security.SecureRandom());            // 使用上面创建的SSLContext创建一个SSLSocketFactory            javax.net.ssl.SSLSocketFactory sslSocketFactory = sslContext.getSocketFactory();            OkHttpClient.Builder builder = new OkHttpClient.Builder();            builder.sslSocketFactory(sslSocketFactory, (X509TrustManager) trustAllCerts[0]);            builder.hostnameVerifier((hostname, session) -> true);            builder.readTimeout(1, TimeUnit.MINUTES);            return builder.build();        } catch (Exception e) {            throw new RuntimeException(e);        }    }    public static void main(String[] args) throws Exception {                // 发送请求        Request request = new Request.Builder()                .url("https://example.com")                .build();        Response response = getUnsafeOkHttpClient().newCall(request).execute();        System.out.println(response.body().string());    }

        CloseableHttpClient请求

public static void main(String[] args) throws Exception {        // 创建SSL上下文，忽略证书验证        SSLContextBuilder sslContextBuilder = SSLContexts.custom().loadTrustMaterial((chain, authType) -> true);        SSLConnectionSocketFactory sslSocketFactory = new SSLConnectionSocketFactory(sslContextBuilder.build(), NoopHostnameVerifier.INSTANCE);        // 创建 CloseableHttpClient 对象        CloseableHttpClient httpClient = HttpClients.custom()                .setSSLSocketFactory(sslSocketFactory)                .build();        // 创建 HttpGet 对象，并设置请求URL        HttpGet httpGet = new HttpGet("https://lmg.jj20.com/up/allimg/4k/s/02/2109250006343S5-0-lp.jpg");        // 设置请求头参数        httpGet.setHeader("User-Agent", "Mozilla/5.0");        // 发送请求，获取响应        HttpResponse response = httpClient.execute(httpGet);        // 获取响应实体        HttpEntity entity = response.getEntity();        // 读取响应内容        String responseBody = EntityUtils.toString(entity);        // 输出响应        System.out.println("Response Code: " + response.getStatusLine().getStatusCode());        System.out.println("Response Body: " + responseBody);        // 关闭httpClient        httpClient.close();    }

        HttpURLConnection请求

//忽略SSL验证    public static void ignoreSSL() throws NoSuchAlgorithmException, KeyManagementException {        SSLContext sslContext = SSLContext.getInstance("TLS");        TrustManager[] trustManagers = new TrustManager[]{new X509TrustManager() {            @Override            public void checkClientTrusted(java.security.cert.X509Certificate[] x509Certificates, String s) {}            @Override            public void checkServerTrusted(java.security.cert.X509Certificate[] x509Certificates, String s) {}            @Override            public java.security.cert.X509Certificate[] getAcceptedIssuers() {                return null;            }        }};        sslContext.init(null, trustManagers, new java.security.SecureRandom());        HttpsURLConnection.setDefaultSSLSocketFactory(sslContext.getSocketFactory());    }    public static void main(String[] args) throws Exception {        ignoreSSL();        // 创建URL对象        URL url = new URL("https://lmg.jj20.com/up/allimg/4k/s/02/2109250006343S5-0-lp.jpg");        // 打开连接        HttpURLConnection connection = (HttpURLConnection) url.openConnection();        // 设置请求头参数        connection.setRequestMethod("GET");        connection.setRequestProperty("User-Agent", "Mozilla/5.0");        // 发送请求        int responseCode = connection.getResponseCode();        // 读取响应        BufferedReader reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));        String line;        StringBuilder response = new StringBuilder();        while ((line = reader.readLine()) != null) {            response.append(line);        }        reader.close();        // 输出响应        System.out.println("Response Code: " + responseCode);        System.out.println("Response Body: " + response.toString());        // 关闭连接        connection.disconnect();    }

        RestTemplate请求

public static void ignoreSSL() throws NoSuchAlgorithmException, KeyManagementException {        SSLContext sslContext = SSLContext.getInstance("TLS");        TrustManager[] trustManagers = new TrustManager[]{new X509TrustManager() {            @Override            public void checkClientTrusted(java.security.cert.X509Certificate[] x509Certificates, String s) {}            @Override            public void checkServerTrusted(java.security.cert.X509Certificate[] x509Certificates, String s) {}            @Override            public java.security.cert.X509Certificate[] getAcceptedIssuers() {                return null;            }        }};        sslContext.init(null, trustManagers, new java.security.SecureRandom());        HttpsURLConnection.setDefaultSSLSocketFactory(sslContext.getSocketFactory());    }    public static void main(String str[]) throws Exception{        ignoreSSL();        RestTemplate restTemplate = new RestTemplate();        ResponseEntity response = restTemplate.getForEntity("https://lmg.jj20.com/up/allimg/4k/s/02/2109250006343S5-0-lp.jpg", String.class);        System.out.println(response.getBody());    }

2.添加证书到本地证书库

• 获取证书，首先确保您访问的HTTPS网站具有有效的SSL证书。可以通过浏览器访问该网站并查看并导出证书。

   

  • 导入SSL证书：将SSL证书导入到Java的信任存储库中。可以使用keytool命令行工具执行此操作。运行以下命令将证书导入到默认的JDK信任存储库中

    1. keytool -import -alias alias_name -keystore path_to_jdk_cacerts -file path_to_certificate-- alias_name 证书指定的别名-- path_to_jdk_cacerts是JDK信任存储库的路径，默认路径为$JAVA_HOME/jre/lib/security/cacerts，-- path_to_certificate是下载的SSL证书的路径