java – 用户’root’@’localhost’拒绝访问
作者：互联网
我试图从数据库中获取记录.但我面临这个访问被拒绝的问题.我尝试了Stack Overflow上提到的其他解决方案,例如向用户授予权限..但没有一个工作.
访问数据库的代码：
public void service(HttpServletRequest request,HttpServletResponse response) throws IOException, ServletException{
response.setContentType("text/html");
PrintWriter out = response.getWriter();
out.println("<html>");
out.println("<head><title>Servlet JDBC</title></head>");
out.println("<body>");
out.println("<h1>Servlet JDBC</h1>");
out.println("</body></html>");
// connecting to database
Connection con = null;
Statement stmt = null;
ResultSet rs = null;
try {
Class.forName("com.mysql.jdbc.Driver");
con = DriverManager.getConnection("jdbc:mysql://localhost:3306/employees","root","root");
stmt = con.createStatement();
rs = stmt.executeQuery("SELECT * FROM employee");
// displaying records
while(rs.next()){
out.print(rs.getObject(1).toString());
out.print("\t\t\t");
out.print(rs.getObject(2).toString());
out.print("<br>");
}
} catch (SQLException e) {
throw new ServletException("Servlet Could not display records.", e);
} catch (ClassNotFoundException e) {
throw new ServletException("JDBC Driver not found.", e);
} finally {
try {
if(rs != null) {
rs.close();
rs = null;
}
if(stmt != null) {
stmt.close();
stmt = null;
}
if(con != null) {
con.close();
con = null;
}
} catch (SQLException e) {}
}
out.close();
}
堆栈跟踪错误：
java.sql.SQLException: Access denied for user 'root'@'localhost' (using password: YES)
com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1078)
com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4187)
com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4119)
com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:927)
com.mysql.jdbc.MysqlIO.secureAuth411(MysqlIO.java:4686)
com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1304)
com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2483)
com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2516)
com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2301)
com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:834)
com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:47)
sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
java.lang.reflect.Constructor.newInstance(Unknown Source)
com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:416)
com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:346)
java.sql.DriverManager.getConnection(Unknown Source)
java.sql.DriverManager.getConnection(Unknown Source)
WebAppAss.DatabaseAccess.service(DatabaseAccess.java:36)
javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
在这种情况下可能会出现什么问题.我尝试创建一个新数据库,但这也不起作用.
解决方法:
在控制台中启动mysql客户端并执行此查询：从mysql.user;中选择Host,User.你必须有这样一行：
+----------------+------------------+ | Host | User | +----------------+------------------+ | localhost | root | +----------------+------------------+
在Host中使用“localhost”并在User中使用“root”的行.如果你没有这就是问题的原因(如果你在User中有其他行“root”并不重要)
如果您没有这样的行,请添加一个新用户：
CREATE USER 'appUser'@'localhost' IDENTIFIED BY 'appPassword';
如果需要,可以通过“root”更改“appUser”,但我强烈建议您使用其他用户.然后通过在mysql客户端中执行此操作为新用户添加权限：
GRANT ALL PRIVILEGES ON employees.* TO 'appUser'@'localhost';
(再次,如果你愿意,可以通过’root’更改’appUser’)
标签：access-denied,java,mysql,jdbc 来源： https://codeday.me/bug/20190923/1814345.html