Question

使用mac Yosemite上的java连接到mysql数据库，并在CLASS PATH中连接到jdbcdriver jar文件的完整url。 netbeans控制台提供了＆＃34; java.sql.SQLException：拒绝访问用户＆root;＆＃39; @＆＃39; localhost＆＃39; （使用密码：是）。＆＃34;我作为论坛尝试了很多方法，但它仍然不起作用。

这是我的代码

//STEP 1. Import required packages
import java.sql.*;

public class JDBCExample {
   // JDBC driver name and database URL
   static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";  
   static final String DB_URL = "jdbc:mysql://localhost:3307/library";

   //  Database credentials
   static final String USER = "root";
   static final String PASS = "default$";

   public static void main(String[] args) {
   Connection conn = null;
   Statement stmt = null;
   ResultSet rs = null;
   try{
      //STEP 2: Register JDBC driver (automatically done since JDBC 4.0)
      Class.forName("com.mysql.jdbc.Driver");

      //STEP 3: Open a connection
      System.out.println("Connecting to database...");
      conn = DriverManager.getConnection(DB_URL, USER, PASS);

      //STEP 4: Execute a query
      System.out.println("Creating database...");
      stmt = conn.createStatement();
      rs = stmt.executeQuery("select uid uname from User");

      //STEP 5: Process the results
      while(rs.next()){
          System.out.println("User ID="+rs.getInt("uid")+", Name="+rs.getString("uname"));
      }

   }catch(SQLException se){
      //Handle errors for JDBC
      se.printStackTrace();
   }catch(Exception e){
      //Handle errors for Class.forName
      e.printStackTrace();
   }finally{
      //finally block used to close resources
      try{
         if(stmt!=null)
            stmt.close();
      }catch(SQLException se2){
      }// nothing we can do
      try{
         if(conn!=null)
            conn.close();
      }catch(SQLException se){
         se.printStackTrace();
      }//end finally try
   }//end try
   System.out.println("Goodbye!");
}//end main
}//end JDBCExample

以下是结果：

Connection Failed! Check output console
java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: YES)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:959)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3870)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3806)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:871)
    at com.mysql.jdbc.MysqlIO.proceedHandshakeWithPluggableAuthentication(MysqlIO.java:1686)
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1207)
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2254)
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2285)
    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 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:408)
    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 com.mysql.jdbc.jdbc2.optional.MysqlDataSource.getConnection(MysqlDataSource.java:422)
    at com.mysql.jdbc.jdbc2.optional.MysqlDataSource.getConnection(MysqlDataSource.java:134)
    at com.mysql.jdbc.jdbc2.optional.MysqlDataSource.getConnection(MysqlDataSource.java:105)
    at cs157a_test.DataSourceTester.main(DataSourceTester.java:54)

Answer 1

您获得的例外情况是告诉您已成功连接到服务器，但不允许/允许用户root从localhost进行连接。

您必须查看您的mysql用户权限表，并确保您有一行允许root使用正确的密码从localhost进行连接。

以下SQL将显示：

SELECT host, user FROM mysql.user;

如果root和localhost或root和%有一行，则必须使用此SQL重置密码：

set password for 'root'@'localhost' = password('your_password');

如果没有行，则必须创建它，然后在要与该用户访问的数据库上设置权限。

您可以使用以下SQL实现此目的：

CREATE USER 'root'@'localhost' IDENTIFIED BY 'your_password';
GRANT ALL ON YOU_DATABASES.* TO 'root'@'localhost';

最后你必须刷新权限或重启mysql。再试一次，确保你会得到连接。

Answer 2

你想看看吗？它对我有用。

    import java.*;
    import java.sql.*;
    import java.util.*;
    //STEP 1. Import required packages
    import java.sql.*;

    public class Memory {
     // JDBC driver name and database URL
     static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";  
     static final String DB_URL = "jdbc:mysql://localhost:3306/library";

     //  Database credentials
     static final String USER = "root";
     static final String PASS = "root";

     public static void main(String[] args) {
     Connection conn = null;
     Statement stmt = null;
     ResultSet rs = null;

     try{
        //STEP 2: Register JDBC driver (automatically done since JDBC 4.0)
        Class.forName("com.mysql.jdbc.Driver");

        //STEP 3: Open a connection
        System.out.println("Connecting to database...");
        conn = DriverManager.getConnection(DB_URL, USER, PASS);

        //STEP 4: Execute a query
        System.out.println("Creating database...");
        stmt = conn.createStatement();
        rs = stmt.executeQuery("select uid, uname from uisend");

        //STEP 5: Process the results
        while(rs.next()){
            System.out.println("User ID="+rs.getInt("uid")+", Name="+rs.getString("uname"));
        }

     }catch(SQLException se){
        //Handle errors for JDBC
        se.printStackTrace();
     }catch(Exception e){
        //Handle errors for Class.forName
        e.printStackTrace();
     }finally{
        //finally block used to close resources
        try{
           if(stmt!=null)
              stmt.close();
        }catch(SQLException se2){
        }// nothing we can do
        try{
           if(conn!=null)
              conn.close();
        }catch(SQLException se){
           se.printStackTrace();
        }//end finally try
     }//end try
     System.out.println("Goodbye!");
    }//end main
    }//end JDBCExample

Answer 3

我不知道为什么它可以作为我的代码而且不需要改变。

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连接失败！检查输出控制台

3 个答案: