异常关键词：
javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
下载代码
public static void main(String[] args) {
HttpURLConnection connection = null;
try {
String url2 = "http://www.***.com/4f913bb5927_3864.pdf";
URL url = new URL(url2);
HttpURLConnection conn = (HttpURLConnection)url.openConnection();
//设置超时间为3秒
conn.setConnectTimeout(3*1000);
//得到输入流
InputStream inputStream = conn.getInputStream();
//获取自己数组
byte[] getData = readInputStream(inputStream);
//文件保存位置
File saveDir = new File("K:\\home\\q\\");
if(!saveDir.exists()){
saveDir.mkdir();
}
String fileName = "123.pdf";
File file = new File(saveDir+File.separator+fileName);
FileOutputStream fos = new FileOutputStream(file);
fos.write(getData);
if(fos!=null){
fos.close();
}
if(inputStream!=null){
inputStream.close();
}
System.out.println("info:"+url+" download success");
} catch (Exception e) {
System.out.println(e);
}finally {
if (null != connection) {
connection.disconnect();
}
}
}保存的文件打不开，通过byte数据可以看到301了。
<html>
<head><title>301 Moved Permanently</title></head>
<body>
<center><h1>301 Moved Permanently</h1></center>
<hr><center>nginx/1.18.0</center>
</body>
</html>
通过 conn.getHeaderFields() 发现url重定向到了 https请求，
进行重定向后的url获取：
String newUrl = "";
if(conn.getHeaderFields().keySet().contains("Location")){
newUrl = conn.getHeaderFields().get("Location").get(0);
}
url = new URL(newUrl);
HttpURLConnection conn2 = (HttpURLConnection)url.openConnection();
//设置超时间为3秒
conn2.setConnectTimeout(3*1000);执行报错：
javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
解决SSL问题，修改为https，并忽略验证，否则会报错
url = new URL(newUrl);
HttpsURLConnection conn2 = (HttpsURLConnection)url.openConnection();
//设置超时间为3秒
conn2.setConnectTimeout(3*1000);
conn2.setHostnameVerifier(DO_NOT_VERIFY);这时候，报证书问题了：
javax.net.ssl.SSLHandshakeException: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
最后解决：
/**
* 从输入流中获取字节数组
* @param inputStream
* @return
* @throws IOException
*/
public static byte[] readInputStream(InputStream inputStream) throws IOException {
byte[] buffer = new byte[1024];
int len = 0;
ByteArrayOutputStream bos = new ByteArrayOutputStream();
while((len = inputStream.read(buffer)) != -1) {
bos.write(buffer, 0, len);
}
bos.close();
return bos.toByteArray();
}
final static HostnameVerifier DO_NOT_VERIFY = new HostnameVerifier() {
@Override
public boolean verify(String s, SSLSession sslSession) {
return true;
}
};
public static void main(String[] args) {
HttpURLConnection connection = null;
try {
String url2 = "http://wechaapi.xmskygzc.com/data/datafile/onlineService/signFile/2022/03/07/4be5418407e24209a0ac24f913bb5927_3864.pdf";
URL url = new URL(url2);
HttpURLConnection conn = (HttpURLConnection)url.openConnection();
String newUrl = "";
if(conn.getHeaderFields().keySet().contains("Location")){
newUrl = conn.getHeaderFields().get("Location").get(0);
}
url = new URL(newUrl);
HttpsURLConnection conn2 = (HttpsURLConnection)url.openConnection();
//设置超时间为3秒
conn2.setConnectTimeout(3*1000);
conn2.setHostnameVerifier(DO_NOT_VERIFY);
//得到输入流
InputStream inputStream = conn2.getInputStream();
//获取自己数组
byte[] getData = readInputStream(inputStream);
//文件保存位置
File saveDir = new File("K:\\home\\q\\");
if(!saveDir.exists()){
saveDir.mkdir();
}
String fileName = "123.pdf";
File file = new File(saveDir+File.separator+fileName);
FileOutputStream fos = new FileOutputStream(file);
fos.write(getData);
if(fos!=null){
fos.close();
}
if(inputStream!=null){
inputStream.close();
}
System.out.println("info:"+url+" download success");
} catch (Exception e) {
System.out.println(e);
}finally {
if (null != connection) {
connection.disconnect();
}
}
}
public static void main2(String[] args) {
HttpURLConnection connection = null;
try {
String url2 = "http://www.***.com/e5418407e29a0ac24f913bb5927_3864.pdf";
URL url = new URL(url2);
HttpURLConnection conn = (HttpURLConnection)url.openConnection();
String newUrl = "";
if(conn.getHeaderFields().keySet().contains("Location")){
newUrl = conn.getHeaderFields().get("Location").get(0);
}
url = new URL(newUrl);
ignoreSsl();
HttpsURLConnection conn2 = (HttpsURLConnection)url.openConnection();
//设置超时间为3秒
conn2.setConnectTimeout(3*1000);
conn2.setHostnameVerifier(DO_NOT_VERIFY);
//得到输入流
InputStream inputStream = conn2.getInputStream();
//获取自己数组
byte[] getData = readInputStream(inputStream);
//文件保存位置
File saveDir = new File("K:\\home\\q\\");
if(!saveDir.exists()){
saveDir.mkdir();
}
String fileName = "123.pdf";
File file = new File(saveDir+File.separator+fileName);
FileOutputStream fos = new FileOutputStream(file);
fos.write(getData);
if(fos!=null){
fos.close();
}
if(inputStream!=null){
inputStream.close();
}
System.out.println("info:"+url+" download success");
} catch (Exception e) {
System.out.println(e);
}finally {
if (null != connection) {
connection.disconnect();
}
}
}
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;
}
}
/**
* 忽略HTTPS请求的SSL证书，必须在openConnection之前调用
* @throws Exception
*/
public static void ignoreSsl() throws Exception{
HostnameVerifier hv = new HostnameVerifier() {
public boolean verify(String urlHostName, SSLSession session) {
System.out.println("Warning: URL Host: " + urlHostName + " vs. " + session.getPeerHost());
return true;
}
};
trustAllHttpsCertificates();
HttpsURLConnection.setDefaultHostnameVerifier(hv);
}
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