package org.example;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
public class Main {
public static void main(String[] args) throws Exception {
Class.forName("com.mysql.cj.jdbc.Driver");
//String url="jdbc:mysql://localhost:3306/jdbcstudy?useUnicode=true&characterEncoding=utf8&useSSL=false";
String url="jdbc:mysql://127.0.0.1:3306/db1";
//String url=" jdbc:mysql://192.168.56.10:3306/gulimall_admin?useUnicode=true&useSSL=false&characterEncoding=UTF-8&serverTimezone=Asia/Shanghai";
String username="root";
String password="321116";
Connection conn= DriverManager.getConnection(url,username,password);
String sql="update tb_user set password=465728 where id=1";
Statement stmt=conn.createStatement();
int count=stmt.executeUpdate(sql);
System.out.println(count);
stmt.close();
conn.close();
}
}
报错提示：
Exception in thread "main" com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
at com.mysql.cj.jdbc.exceptions.SQLError.createCommunicationsException(SQLError.java:174)
at com.mysql.cj.jdbc.exceptions.SQLExceptionsMapping.translateException(SQLExceptionsMapping.java:64)
at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:835)
at com.mysql.cj.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:455)
at com.mysql.cj.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:240)
at com.mysql.cj.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:207)
at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:683)
at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:230)
at org.example.Main.main(Main.java:17)
Caused by: com.mysql.cj.exceptions.CJCommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
at java.base/jdk.internal.reflect.DirectConstructorHandleAccessor.newInstance(DirectConstructorHandleAccessor.java:67)
at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:500)
at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:484)
at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:61)
at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:105)
at com.mysql.cj.exceptions.ExceptionFactory.createException(ExceptionFactory.java:151)
at com.mysql.cj.exceptions.ExceptionFactory.createCommunicationsException(ExceptionFactory.java:167)
at com.mysql.cj.protocol.a.NativeProtocol.negotiateSSLConnection(NativeProtocol.java:351)
at com.mysql.cj.protocol.a.NativeAuthenticationProvider.negotiateSSLConnection(NativeAuthenticationProvider.java:777)
at com.mysql.cj.protocol.a.NativeAuthenticationProvider.proceedHandshakeWithPluggableAuthentication(NativeAuthenticationProvider.java:486)
at com.mysql.cj.protocol.a.NativeAuthenticationProvider.connect(NativeAuthenticationProvider.java:202)
at com.mysql.cj.protocol.a.NativeProtocol.connect(NativeProtocol.java:1442)
at com.mysql.cj.NativeSession.connect(NativeSession.java:165)
at com.mysql.cj.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:955)
at com.mysql.cj.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:825)
... 6 more
Caused by: javax.net.ssl.SSLHandshakeException: No appropriate protocol (protocol is disabled or cipher suites are inappropriate)
at java.base/sun.security.ssl.HandshakeContext.<init>(HandshakeContext.java:172)
at java.base/sun.security.ssl.ClientHandshakeContext.<init>(ClientHandshakeContext.java:103)
at java.base/sun.security.ssl.TransportContext.kickstart(TransportContext.java:240)
at java.base/sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:448)
at java.base/sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:426)
at com.mysql.cj.protocol.ExportControlled.performTlsHandshake(ExportControlled.java:315)
at com.mysql.cj.protocol.StandardSocketFactory.performTlsHandshake(StandardSocketFactory.java:188)
at com.mysql.cj.protocol.a.NativeSocketConnection.performTlsHandshake(NativeSocketConnection.java:99)
at com.mysql.cj.protocol.a.NativeProtocol.negotiateSSLConnection(NativeProtocol.java:347)
... 13 more
指定时区serverTimezone=UTC
String url="jdbc:mysql://127.0.0.1:3306/db1";
->
String url="jdbc:mysql://127.0.0.1:3306/db1?useSSL=false"
该回答引用ChatGPT4与博主@晓码自在合作编写：
根据报错信息,这是一个连接 MySQL 数据库失败的错误。错误信息显示是 SSL 连接失败导致的。
解决方法如下:
String url="jdbc:<mysql://127.0.0.1:3306/db1?useSSL=false";