Java向指定URL发送请求出现net.ssl.SSLHandshakeException: PKIX path building failed异常

1 Java在做向指定 Url 发送 get 请求时报错

1.1 异常信息：javax.net.ssl.SSLHandshakeException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

 

2 原因分析

1. 网上搜的：google发现stackoverflow上不少人反应，twitter和新浪微博的api也会报这个异常，不少人反映客户端需要导入证书，其实大可不必，如果要导证书的话，用户不得哭了。。

2. 我是做WebSSO单点登录，要调到统一授权页面获取Xml信息，获取结果的时候报的错。

3. 用的第一种方式发送get请求，报这个错误！！！

/**
     * 向指定的地址发送get请求
     *
     * @param url
     * @return
     */
    public static String getRequest(String url) {
        try {
            URL urlObj = new URL(url);
            URLConnection connection = urlObj.openConnection();
            InputStream is = connection.getInputStream();
            byte[] b = new byte[1024];
            int len;
            StringBuilder sb = new StringBuilder();
            while ((len = is.read(b)) != -1) {
                sb.append(new String(b, 0, len));
            }
            return sb.toString();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

3. 换一种发送get请求，还是报这个错误！！！

添加项目依赖

<dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.5.13</version>
</dependency>

测试方法

import java.io.IOException;

import org.apache.http.HttpEntity;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;

public class SendGetRequest {

    public static void main(String[] args) throws IOException {
        // 向url发送GET请求
        String url = "";
        CloseableHttpClient httpClient = HttpClients.createDefault();
        try {
            HttpGet httpGet = new HttpGet(url);
            CloseableHttpResponse httpResponse = httpClient.execute(httpGet);
            try {
                System.out.println(httpResponse.getStatusLine());
                HttpEntity httpEntity = httpResponse.getEntity();
                // 添加处理返回数据的代码
                // 例如将返回的数据转换为字符串并输出
                System.out.println(EntityUtils.toString(httpEntity));
                EntityUtils.consume(httpEntity);
            } finally {
                httpResponse.close();
            }
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            httpClient.close();
        }
    }
}

3 解决方法

3.1 我的可能是单点登录统一授权的url有限制出现的问题，朋友们可以试下上面两种请求方式

3.2 手动导入证书到本地证书库(不推荐)

可以参考 导入证书

3.3 调整发生请求的代码，信任所有证书

1. trustAllHosts 该方法放任所以请求，不在校验时候有证书

　　 /**
     * Trust every server - dont check for any certificate
     */
    private static void trustAllHosts() {
        final String TAG = "trustAllHosts";
        // Create a trust manager that does not validate certificate chains
        TrustManager[] trustAllCerts = new TrustManager[]{new X509TrustManager() {
            public X509Certificate[] getAcceptedIssuers() {
                return new X509Certificate[]{};
            }

            public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
            }

            public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {
            }
        }};
        // Install the all-trusting trust manager
        try {
            SSLContext sc = SSLContext.getInstance("TLS");
            sc.init(null, trustAllCerts, new java.security.SecureRandom());
            HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

2. https.setHostnameVerifier(DO_NOT_VERIFY); 表示信任所有的证书

final static HostnameVerifier DO_NOT_VERIFY = new HostnameVerifier() {
        public boolean verify(String hostname, SSLSession session) {
            return true;
        }
    };

3. 发送请求的代码

/**
     * 向指定的地址发送get请求忽略证书
     *
     * @param httpUrl
     * @return
     */
    public static String httpGet(String httpUrl) {
        BufferedReader input = null;
        StringBuilder sb = null;
        URL url = null;
        HttpURLConnection con = null;
        try {
            url = new URL(httpUrl);
            trustAllHosts();
            HttpsURLConnection https = (HttpsURLConnection) url.openConnection();
            if (url.getProtocol().toLowerCase().equals("https")) {
                https.setHostnameVerifier(DO_NOT_VERIFY);
                con = https;
            } else {
                con = (HttpURLConnection) url.openConnection();
            }
            input = new BufferedReader(new InputStreamReader(con.getInputStream()));
            sb = new StringBuilder();
            String s;
            while ((s = input.readLine()) != null) {
                sb.append(s).append("\n");
            }
        } catch (Exception e1) {
            e1.printStackTrace();
        } finally {
            // close buffered
            if (input != null) {
                try {
                    input.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            // disconnecting releases the resources held by a connection so they may be closed or reused
            if (con != null) {
                con.disconnect();
            }
        }
        return sb == null ? null : sb.toString();
    }

    final static HostnameVerifier DO_NOT_VERIFY = new HostnameVerifier() {
        public boolean verify(String hostname, SSLSession session) {
            return true;
        }
    };

    /**
     * Trust every server - dont check for any certificate
     */
    private static void trustAllHosts() {
        final String TAG = "trustAllHosts";
        // Create a trust manager that does not validate certificate chains
        TrustManager[] trustAllCerts = new TrustManager[]{new X509TrustManager() {
            public X509Certificate[] getAcceptedIssuers() {
                return new X509Certificate[]{};
            }

            public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
            }

            public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {
            }
        }};
        // Install the all-trusting trust manager
        try {
            SSLContext sc = SSLContext.getInstance("TLS");
            sc.init(null, trustAllCerts, new java.security.SecureRandom());
            HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

4. 完整的工具类代码

package http;

import javax.net.ssl.*;
import java.io.*;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;

/**
 * 向url发送请求
 */
public class SendRequestUtil {

    /**
     * 向指定的地址发送get请求
     *
     * @param url
     * @return
     */
    public static String getRequest(String url) {
        try {
            URL urlObj = new URL(url);
            URLConnection connection = urlObj.openConnection();
            InputStream is = connection.getInputStream();
            byte[] b = new byte[1024];
            int len;
            StringBuilder sb = new StringBuilder();
            while ((len = is.read(b)) != -1) {
                sb.append(new String(b, 0, len));
            }
            return sb.toString();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 向指定的地址发送post请求
     *
     * @param url  url
     * @param data 参数
     * @return
     */
    public static String postRequest(String url, String data) {
        try {
            URL urlObj = new URL(url);
            URLConnection connection = urlObj.openConnection();
            // 发送数据，把状态设置为可发送
            connection.setDoOutput(true);
            // 获取输出流
            OutputStream os = connection.getOutputStream();
            os.write(data.getBytes());
            os.close();
            InputStream is = connection.getInputStream();
            byte[] b = new byte[1024];
            int len;
            StringBuilder sb = new StringBuilder();
            while ((len = is.read(b)) != -1) {
                sb.append(new String(b, 0, len));
            }
            return sb.toString();
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 向指定的地址发送get请求忽略证书
     *
     * @param httpUrl
     * @return
     */
    public static String httpGet(String httpUrl) {
        BufferedReader input = null;
        StringBuilder sb = null;
        URL url = null;
        HttpURLConnection con = null;
        try {
            url = new URL(httpUrl);
            trustAllHosts();
            HttpsURLConnection https = (HttpsURLConnection) url.openConnection();
            if (url.getProtocol().toLowerCase().equals("https")) {
                https.setHostnameVerifier(DO_NOT_VERIFY);
                con = https;
            } else {
                con = (HttpURLConnection) url.openConnection();
            }
            input = new BufferedReader(new InputStreamReader(con.getInputStream()));
            sb = new StringBuilder();
            String s;
            while ((s = input.readLine()) != null) {
                sb.append(s).append("\n");
            }
        } catch (Exception e1) {
            e1.printStackTrace();
        } finally {
            // close buffered
            if (input != null) {
                try {
                    input.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            // disconnecting releases the resources held by a connection so they may be closed or reused
            if (con != null) {
                con.disconnect();
            }
        }
        return sb == null ? null : sb.toString();
    }

    final static HostnameVerifier DO_NOT_VERIFY = new HostnameVerifier() {
        public boolean verify(String hostname, SSLSession session) {
            return true;
        }
    };

    /**
     * Trust every server - dont check for any certificate
     */
    private static void trustAllHosts() {
        final String TAG = "trustAllHosts";
        // Create a trust manager that does not validate certificate chains
        TrustManager[] trustAllCerts = new TrustManager[]{new X509TrustManager() {
            public X509Certificate[] getAcceptedIssuers() {
                return new X509Certificate[]{};
            }

            public void checkClientTrusted(X509Certificate[] chain, String authType) throws CertificateException {
            }

            public void checkServerTrusted(X509Certificate[] chain, String authType) throws CertificateException {
            }
        }};
        // Install the all-trusting trust manager
        try {
            SSLContext sc = SSLContext.getInstance("TLS");
            sc.init(null, trustAllCerts, new java.security.SecureRandom());
            HttpsURLConnection.setDefaultSSLSocketFactory(sc.getSocketFactory());
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}