java连接数据库操作Couldnotcreateconnectiontodatabas

更新时间2019-09-18 06:34:24

public class Demo1

{

public static void main(String[] args) throws Exception{

Class.forName("com.mysql.jdbc.Driver");

Connection conn =DriverManager.getConnection("jdbc:mysql://localhost:3306/jop","root","123");

String sql="update work set sex =500 where id=1";

Statement stmt= conn.createStatement();

int count=stmt.executeUpdate(sql);

System.out.println(count);

stmt.close();

conn.close();

}}

错误提示

Exception in thread "main" com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server.

at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)

at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)

at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)

at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)

at com.mysql.jdbc.Util.getInstance(Util.java:387)

at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:919)

at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:898)

at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:887)

at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:862)

at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2331)

at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2084)

at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:795)

at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:44)

at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)

at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)

at java.base/java.lang.reflect.Constructor.newInstance(Constructor.java:490)

at com.mysql.jdbc.Util.handleNewInstance(Util.java:404)

at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:400)

at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:327)

at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:677)

at java.sql/java.sql.DriverManager.getConnection(DriverManager.java:228)

at cn.jdbc.Jdbc.Demo1.main(Demo1.java:13)

这个应该是你mysql服务的问题，检查你本机mysql有没有启动，检查3306口是否有监听，连接数据库，不是直接一段程序就可以了。首先要用客户端测试下服务是否正常

错误的意思是不能创建对数据库的连接。