mysql用户认证协议更换（mysql使用问题)

安装好mysql后，在使用mysq时，出现了如下问题.
java.sql.SQLException: Communication failure during handshake. Is there a server running on localhost:3306?
at org.gjt.mm.mysql.MysqlIO.init(MysqlIO.java:327)
at org.gjt.mm.mysql.Connection.connectionInit(Connection.java:261)
at org.gjt.mm.mysql.jdbc2.Connection.connectionInit(Connection.java:89)
at org.gjt.mm.mysql.Driver.connect(Driver.java:167)
at java.sql.DriverManager.getConnection(DriverManager.java:523)
MYSQL 4.1以后, 采用了一种新的用户认证协议, 对于老的客户端会出现不支持认证协议的错误, 以下是官方网站的解决方法﹔
1When connecting to the server with a pre-4.1 client program, use an account that still has a pre-4.1-style password.
使用以前建立的账号连接，对于在新的认证协议下建立的账户就不行了
３Reset the password to pre-4.1 style for each user that needs to use a pre-4.1 client program. This can be done using the SET PASSWORD statement and the OLD_PASSWORD() function: mysql> SET PASSWORD FOR 
-> 'some_user'@'some_host' = OLD_PASSWORD('newpwd');
Alternatively, use UPDATE and FLUSH PRIVILEGES: mysql> UPDATE mysql.user SET Password = OLD_PASSWORD('newpwd') -> WHERE Host = 'some_host' AND User = 'some_user'; 
mysql> FLUSH PRIVILEGES;
Substitute the password you want to use for ``newpwd'' in the preceding examples. MySQL cannot tell you what the original password was, so you'll need to pick a new one.
这是一个不错的办法，新建立的账号采用老式的加密协议
４Tell the server to use the older password hashing algorithm: 
Start mysqld with the --old-passwords option.
这样新认证协议的优点就没法使用了
５Assign an old-format password to each account that has had its password updated to the longer 4.1 format. You can identify these accounts with the following query: mysql> SELECT Host, User, Password from mysql.user 
-> WHERE LENGTH(Password) > 16;
For each account record displayed by the query, use the Host and User values and assign a password using th