jdbc - java.sql.SQLException：拒绝访问用户＆root;＆＃39; @＆＃39; localhost＆＃39; （使用密码：是）

Question

我知道有很多主题，有类似的问题，但是没有一个建议的解决方案适合我。

我正在使用MAMP，并尝试使用以下代码连接到已有的现有数据库：

        String url = "jdbc:mysql://localhost:3306/db_name";
        String user = "root";
        String pass = "root";

        try {
            Class.forName("com.mysql.jdbc.Driver").newInstance();
        } catch (ClassNotFoundException ex) {
            System.err.println("Class not found");
            ex.printStackTrace();
        } catch (InstantiationException ex) {
            System.out.println("Instantiation exception");
            ex.printStackTrace();
        } catch (IllegalAccessException ex) {
            System.out.println("Illegal access exception");
            ex.printStackTrace();
        } // catch

        try {
            System.out.println("Connecting to the database..");
            Connection conn = DriverManager.getConnection(url, user, pass); 
            System.out.println("Successfully connected to the database");
        } catch (SQLException ex) {
            System.err.println("Unable to connect to the database");
            ex.printStackTrace();
        } // catch

执行代码时，我得到以下异常：

Unable to connect to the database
java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: YES)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1073)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3609)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3541)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:943)
    at com.mysql.jdbc.MysqlIO.secureAuth411(MysqlIO.java:4113)
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1308)
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2336)
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2369)
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2153)
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:792)
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
    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:422)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:381)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:305)
    at java.sql.DriverManager.getConnection(DriverManager.java:664)
    at java.sql.DriverManager.getConnection(DriverManager.java:247)
    at registrationsystem.SignUpForm.submitJButtonActionPerformed(SignUpForm.java:293)
    at registrationsystem.SignUpForm.access$000(SignUpForm.java:19)
    at registrationsystem.SignUpForm$1.actionPerformed(SignUpForm.java:94)
    at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
    at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
    at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
    at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
    at java.awt.Component.processMouseEvent(Component.java:6535)
    at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
    at java.awt.Component.processEvent(Component.java:6300)
    at java.awt.Container.processEvent(Container.java:2236)
    at java.awt.Component.dispatchEventImpl(Component.java:4891)
    at java.awt.Container.dispatchEventImpl(Container.java:2294)
    at java.awt.Component.dispatchEvent(Component.java:4713)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4888)
    at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4525)
    at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4466)
    at java.awt.Container.dispatchEventImpl(Container.java:2280)
    at java.awt.Window.dispatchEventImpl(Window.java:2750)
    at java.awt.Component.dispatchEvent(Component.java:4713)
    at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
    at java.awt.EventQueue.access$500(EventQueue.java:97)
    at java.awt.EventQueue$3.run(EventQueue.java:709)
    at java.awt.EventQueue$3.run(EventQueue.java:703)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
    at java.awt.EventQueue$4.run(EventQueue.java:731)
    at java.awt.EventQueue$4.run(EventQueue.java:729)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
    at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
    at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
    at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
    at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
    at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
    at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)

到目前为止我为解决问题所做的尝试：

1）执行GRANT ALL PRIVILEGES ON *.* TO 'root'@'localhost' IDENTIFIED BY 'root' WITH GRANT OPTION;

2）尝试创建另一个用户（而不是使用root），但没有任何运气

3）当我运行MAMP时，指定端口3306，用户root和密码root，因此我认为我没有使用错误的密码或端口。

4）我尝试使用

进行连接

conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/db_name?user=root&password=root");