jdbcからmysqlへの例外

Question

jdbc.Thisタイプのmysqlを使用して接続しようとしたときに例外が発生しました。すでに質問されていますが、私の問題の解決方法は得られませんでした。ここに私のコードです...

run: 
Now connecting to databse... 

com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server. Attempted reconnect 3 times. Giving up. 
com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server. Attempted reconnect 3 times. Giving up. 
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) 
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) 
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) 
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423) 
    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:917) 
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:896) 
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:885) 
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:860) 
    at com.mysql.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:2165) 
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2090) 
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:795) 
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:44) 
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) 
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) 
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) 
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423) 
    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.DriverManager.getConnection(DriverManager.java:664) 
    at java.sql.DriverManager.getConnection(DriverManager.java:247) 
    at dbms_basic.Dbms_Basic.main(Dbms_Basic.java:28) 
Caused by: java.lang.NullPointerException 
    at com.mysql.jdbc.ConnectionImpl.getServerCharset(ConnectionImpl.java:3005) 
    at com.mysql.jdbc.MysqlIO.sendConnectionAttributes(MysqlIO.java:1916) 
    at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1845) 
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1215) 
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2255) 
    at com.mysql.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:2106) 
    ... 13 more 
BUILD SUCCESSFUL (total time: 4 seconds) 

誰かが私はこのエラーを解決するのに役立ち

public static void main(String[] args) { 
    String url="jdbc:mysql://localhost:3306/student? 
    autoReconnect=true&useSSL=false"; 
    String user="root"; 
    String pass="system"; 
    try { 
     Class.forName("com.mysql.jdbc.Driver"); 

     System.out.println("Now connecting to databse...\n"); 
     Connection con=DriverManager.getConnection(url,user,pass); 
     System.out.println("Connected !!!\n"); 
     con.close(); 
     System.out.println("connection close !!!\n"); 

    } catch (ClassNotFoundException | SQLException e) {System.out.println(e); 
    e.printStackTrace(); 
    } 
} 

}

これらは私が得た例外では... ..

Answer 1

私は、例えば、あなたが慎重にスタックトレースを読む次のURL

String url="jdbc:mysql://localhost:3306/student?autoReconnect=true&useSSL=false&characterEncoding=utf8&useUnicode=true";