java.sql.SQLException：拒绝用户“用户名”@“本地主机”的访问（使用密码：是）

java.sql.SQLException: Access denied for user 'username'@'localhost' (using pass word: YES)

提问by user3116798

I'm so grateful for the guys who have assisted me with advice on my previous post of the program below. This is my first sql-java (database) program, though I have some basic college knowledge of the two languages. I set my CLASSPATH via environment variable as per advice and YES the FirstExample.java / FirstExample.class is successfully compiled by Java Compiler and recognized at run time of the the JVM in the command line unlike before.
But then while trying to connect to the database I receive a long error message that I can't understand.
I'm a bit suspicious this could bit arising from 'username' issue, though I'm not really sure as I'm a newbie with database programing.
I'm wondering neither in the MySQL configuration wizard nor SQL -database design does 'username' appear though it's part of my tutorial FirstExample.java.

我非常感谢那些在我之前发布的程序中为我提供建议的人。这是我的第一个 sql-java（数据库）程序，尽管我对这两种语言有一些基本的大学知识。我根据建议通过环境变量设置了我的 CLASSPATH，是的，Java 编译器成功编译了 FirstExample.java / FirstExample.class，并在命令行中的 JVM 运行时识别，与以前不同。
但是在尝试连接到数据库时，我收到了一条我无法理解的长错误消息。
我有点怀疑这可能是由“用户名”问题引起的，尽管我不太确定，因为我是数据库编程的新手。
我不知道在 MySQL 配置向导和 SQL 数据库设计中都没有出现“用户名”，尽管它是我的教程 FirstExample.java 的一部分。

Please assist with solving this problem giving me head ache the whole day, thanks in advance.

请协助解决这个让我头疼一整天的问题，提前致谢。

Below is the command line error message:

下面是命令行错误信息：

 Connecting to database...
java.sql.SQLException: Access denied for user 'username'@'localhost' (using pass
word: YES)
    at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1078)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4237)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4169)
    at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:928)
    at com.mysql.jdbc.MysqlIO.secureAuth411(MysqlIO.java:4736)
    at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1342)
    at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2493)
    at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2
526)
    at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2311)
    at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:834)
    at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstruct
orAccessorImpl.java:39)  
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingC
onstructorAccessorImpl.java:27)  
    at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
    at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
    at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:416)
    at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java
:347)    
    at java.sql.DriverManager.getConnection(DriverManager.java:582)
    at java.sql.DriverManager.getConnection(DriverManager.java:185)
    at FirstExample.main(FirstExample.java:22)  
Goodbye!  

Below is the basic information:
I saved the file as:C:\glassfish3\jdk\jre\lib\FirstExample.javathen compiled to FirstExample.class

以下是基本信息：
我将文件另存为：C:\glassfish3\jdk\jre\lib\FirstExample.java然后编译为FirstExample.class

CLASSPATH:C:\glassfish3\jdk\jre\lib;C:\Program Files (x86)\MySQL\MySQL Connector J\mysql-connector-java-5.1.27-bin.jar

类路径：C:\glassfish3\jdk\jre\lib;C:\Program Files (x86)\MySQL\MySQL Connector J\mysql-connector-java-5.1.27-bin.jar

CATALINA:C:\Program Files\Apache Software Foundation\Tomcat 7.0\lib\jsp-api.jar

卡特琳娜：C:\Program Files\Apache Software Foundation\Tomcat 7.0\lib\jsp-api.jar

JAVA_HOME:C:\glassfish3\jdk

JAVA_主页：C:\glassfish3\jdk

path:C:\glassfish3\jdk\bin;C:\Program Files (x86)\MySQL\MySQL Server 5.0\bin

小路：C:\glassfish3\jdk\bin;C:\Program Files (x86)\MySQL\MySQL Server 5.0\bin

MySQL directory:C:\Program Files (x86)\MySQL\MySQL Server 5.

MySQL目录：C:\Program Files (x86)\MySQL\MySQL Server 5.

Here is the database info:

这是数据库信息：

database - 'EMP'.  
table -  'Employees'.     
password - 'password'   
Columns; id; age; first; last.  
data;   100; 28; Zaid; Khann.   

Java program:

Java程序：

//STEP 1. Import required packages    
import java.sql.*; // for standard JDBC programs    

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

// Database credentials
static final String USER = "username";
static final String PASS = "password";

public static void main(String[] args) {
    Connection conn = null;
    Statement stmt = null;
    try{
        //STEP 2: Register JDBC driver
        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 Statement...");
        stmt = conn.createStatement();
        String sql;
        sql = "SELECT id, first, last, age FROM Employees";
        ResultSet rs = stmt.executeQuery(sql);

        //STEP 5: Extract from result set
        while(rs.next()){
            //Retrieve by column name
            int id = rs.getInt("id");
            int age = rs.getInt("age");
            String first = rs.getString("first");
            String last = rs.getString("last");

            //Display values
            System.out.print("ID: " + id);
            System.out.print(", Age: " + age);
            System.out.print(", First: " + first);
            System.out.print(", Last: " + last);

        }
        //STEP 6: Clean-up enviroment
        rs.close();
        stmt.close();
        conn.close();
    } 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 FirstExample  

This is line 22 of the Java program in code editor:

这是代码编辑器中 Java 程序的第 22 行：

conn = DriverManager.getConnection(DB_URL,USER,PASS); 

回答by Sibbo

You are using usernameas username, passwordas password and you are logging in from localhost. You have to have an entry in the mysql.usertable that corresponds to this.

您正在使用username用户名 password和密码，并且您正在从localhost. 您必须在mysql.user表中具有与此相对应的条目。

Use CREATE USER 'username'@'localhost' IDENTIFIED BY 'password'to create the user you are logging in with.

使用CREATE USER 'username'@'localhost' IDENTIFIED BY 'password'以创建与正在登录用户。

回答by alexiegriffin

Check your username and password, you are using usernameas username and passwordas password, I think that your password is correct (because your database info said so), so you can try to change username to root:

检查您的用户名和密码，您使用用户名作为用户名和密码作为密码，我认为您的密码是正确的（因为您的数据库信息是这样），因此您可以尝试将用户名更改为root：

static final String USER = "root";

静态最终字符串 USER = "root";