问题1
Project build error: Non-resolvable parent POM for com.example:test:0.0.1-SNAPSHOT: Failure to transfer org.springframework.boot:spring-
boot-starter-parent:pom:2.1.9.RELEASE from https://repo.maven.apache.org/maven2 was cached in the local repository, resolution will not be
reattempted until the update interval of central has elapsed or updates are forced. Original error: Could not transfer artifact
org.springframework.boot:spring-boot-starter-parent:pom:2.1.9.RELEASE from/to central (https://repo.maven.apache.org/maven2):
sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find
valid certification path to requested target and ‘parent.relativePath’ points at no local POM
解决方案1
访问 https://repo.maven.apache.org/maven2 ，由于 https的地址左侧都会有个锁标记（绿色代表有该证书合法，红色代表不合法），点击小锁，弹出对话框。在 “连接”栏，单击右侧箭头，显示连接细节
单击“更多信息”，弹出“页面信息”对话框
切换到“安全”选项卡，点击"查看证书"，弹出"证书查看器"对话框
以管理员身份打开cmd，进入到 C:\Program Files\Java\jdk1.8.0_201\jre\lib\security 目录下，执行命令 keytool -keystore cacerts -importcert -alias 【证书文件名】 -file 【crt文件路径】，这里会要求你输入口令，默认的口令是 changeit。
口令也可以通过 -storepass changeit 直接指定
证书文件别名按照原文件名即可， 我这里重命名了，导致导入不成功
最后会询问是否信任，直接回车即可。
解决方案2
创建一个 InstallCert.java类，添加如下代码
package javaDemo;
/*
* Copyright 2006 Sun Microsystems, Inc. All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* - Neither the name of Sun Microsystems nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.security.KeyStore;
import java.security.MessageDigest;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLException;
import javax.net.ssl.SSLSocket;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.TrustManager;
import javax.net.ssl.TrustManagerFactory;
import javax.net.ssl.X509TrustManager;
public class InstallCert {
public static void main(String[] args) throws Exception {
String host;
int port;
char[] passphrase;
if ((args.length == 1) || (args.length == 2)) {
String[] c = args[0].split(":");
host = c[0];
port = (c.length == 1) ? 443 : Integer.parseInt(c[1]);
String p = (args.length == 1) ? "changeit" : args[1];
passphrase = p.toCharArray();
} else {
System.out.println("Usage: java InstallCert <host>[:port] [passphrase]");
return;
}
File file = new File("jssecacerts");
if (file.isFile() == false) {
char SEP = File.separatorChar;
File dir = new File(System.getProperty("java.home") + SEP + "lib"
+ SEP + "security");
file = new File(dir, "jssecacerts");
if (file.isFile() == false) {
file = new File(dir, "cacerts");
}
}
System.out.println("Loading KeyStore " + file + "...");
InputStream in = new FileInputStream(file);
KeyStore ks = KeyStore.getInstance(KeyStore.getDefaultType());
ks.load(in, passphrase);
in.close();
SSLContext context = SSLContext.getInstance("TLS");
TrustManagerFactory tmf = TrustManagerFactory
.getInstance(TrustManagerFactory.getDefaultAlgorithm());
tmf.init(ks);
X509TrustManager defaultTrustManager = (X509TrustManager) tmf
.getTrustManagers()[0];
SavingTrustManager tm = new SavingTrustManager(defaultTrustManager);
context.init(null, new TrustManager[] { tm }, null);
SSLSocketFactory factory = context.getSocketFactory();
System.out
.println("Opening connection to " + host + ":" + port + "...");
SSLSocket socket = (SSLSocket) factory.createSocket(host, port);
socket.setSoTimeout(10000);
try {
System.out.println("Starting SSL handshake...");
socket.startHandshake();
socket.close();
System.out.println();
System.out.println("No errors, certificate is already trusted");
} catch (SSLException e) {
System.out.println();
e.printStackTrace(System.out);
}
X509Certificate[] chain = tm.chain;
if (chain == null) {
System.out.println("Could not obtain server certificate chain");
return;
}
BufferedReader reader = new BufferedReader(new InputStreamReader(
System.in));
System.out.println();
System.out.println("Server sent " + chain.length + " certificate(s):");
System.out.println();
MessageDigest sha1 = MessageDigest.getInstance("SHA1");
MessageDigest md5 = MessageDigest.getInstance("MD5");
for (int i = 0; i < chain.length; i++) {
X509Certificate cert = chain[i];
System.out.println(" " + (i + 1) + " Subject "
+ cert.getSubjectDN());
System.out.println(" Issuer " + cert.getIssuerDN());
sha1.update(cert.getEncoded());
System.out.println(" sha1 " + toHexString(sha1.digest()));
md5.update(cert.getEncoded());
System.out.println(" md5 " + toHexString(md5.digest()));
System.out.println();
}
System.out
.println("Enter certificate to add to trusted keystore or 'q' to quit: [1]");
String line = reader.readLine().trim();
int k;
try {
k = (line.length() == 0) ? 0 : Integer.parseInt(line) - 1;
} catch (NumberFormatException e) {
System.out.println("KeyStore not changed");
return;
}
X509Certificate cert = chain[k];
String alias = host + "-" + (k + 1);
ks.setCertificateEntry(alias, cert);
OutputStream out = new FileOutputStream("jssecacerts");
ks.store(out, passphrase);
out.close();
System.out.println();
System.out.println(cert);
System.out.println();
System.out
.println("Added certificate to keystore 'jssecacerts' using alias '"
+ alias + "'");
}
private static final char[] HEXDIGITS = "0123456789abcdef".toCharArray();
private static String toHexString(byte[] bytes) {
StringBuilder sb = new StringBuilder(bytes.length * 3);
for (int b : bytes) {
b &= 0xff;
sb.append(HEXDIGITS[b >> 4]);
sb.append(HEXDIGITS[b & 15]);
sb.append(' ');
}
return sb.toString();
}
private static class SavingTrustManager implements X509TrustManager {
private final X509TrustManager tm;
private X509Certificate[] chain;
SavingTrustManager(X509TrustManager tm) {
this.tm = tm;
}
public X509Certificate[] getAcceptedIssuers() {
throw new UnsupportedOperationException();
}
public void checkClientTrusted(X509Certificate[] chain, String authType)
throws CertificateException {
throw new UnsupportedOperationException();
}
public void checkServerTrusted(X509Certificate[] chain, String authType)
throws CertificateException {
this.chain = chain;
tm.checkServerTrusted(chain, authType);
}
}
}
在 run configurations 对话框中添加如下配置
直接回车即可
将证书拷贝到$JAVA_HOME/jre/lib/security目录下，重新编译即可
解决方案3
换一个 workspace，新建项目
问题2
Failure to transfer org.springframework.boot:spring-boot-maven-plugin:pom:2.1.6.RELEASE from https://repo.maven.apache.org/maven2 was cached in the
local repository, resolution will not be reattempted until the update interval of central has elapsed or updates are forced. Original error: Could not transfer
artifact org.springframework.boot:spring-boot-maven-plugin:pom:2.1.6.RELEASE from/to central (https://repo.maven.apache.org/maven2):
repo.maven.apache.org
解决方案
上面说明使用的是本地仓库缓存下来的包，但缓存的包有问题，因此只能删除 repository 目录下的所有的包，然后 clean 项目，让其重新构建了。
补充
如果不是公司装的代理服务器把证书换了导致不能访问。可能是当前版本的JDK太旧了，已不再支持，可以卸载，然后装一个新版的，装完之后重启电脑试试。
jre11 开始，安装 jdk 之后，虽然jdk自带 jre，但目录下却没有原本的 jre 文件夹，这导致很多依赖于 jre 的软件都无法正常运行。可以使用命令 bin\jlink.exe --module-path jmods --add-modules java.desktop --output jre 在 jdk 目录下生成 jre 文件夹