Error 1045 mysql new installation on OSX 10.9.3

after new mysql-5.7.4-m14-osx10.7-x86_64 installation,

I typed "/usr/local/mysql/bin/mysql" I got "ERROR 1045 (28000): Access denied for user 'username'@'localhost' (using password: NO)"

I type "ps auxww | grep mysql", I got"

_mysql 224 0.0 6.6 3188416 552216 ?? S 7:58pm 0:01.50 /usr/local/mysql/bin/mysqld --basedir=/usr/local/mysql --datadir=/usr/local/mysql/data --plugin-dir=/usr/local/mysql/lib/plugin --user=mysql --log-error=/usr/local/mysql/data/Dongs-MacBook-Pro.local.err --pid-file=/usr/local/mysql/data/Dongs-MacBook-Pro.local.pid --socket=/var/mysql/mysql.sock --port=8888

root 65 0.0 0.0 2461016 1064 ?? Ss 7:58pm 0:00.04 /bin/sh /usr/local/mysql/bin/mysqld_safe --user=mysql

dongzhong 594 0.0 0.0 2432784 604 s000 S+ 8:56pm 0:00.00 grep mysql"

I type "sudo nano /Library/LaunchDaemons/com.mysql.mysql.plist", I got

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-$

<plist version="1.0">

<dict>

<key>KeepAlive</key>

<true/>

<key>Label</key>

<string>com.mysql.mysqld</string>

<key>ProgramArguments</key>

<array>

<string>/usr/local/mysql/bin/mysqld_safe</string>

<string>--user=mysql</string>

</array>

</dict>

</plist>

I also have turned on my internet sharing but still access denial. Please help me