tring userName){
        this.userName = userName;
    }

    public SimpleUser getFriend(){
        return friend;
    }

    public void setFriend(SimpleUser friend){
        this.friend = friend;
    }

}
</pre>



<pre class="prettyprint lang-java">
public class BookVO implements Serializable{

    private long bookId; //图书id
    private String bookName; //图书名称
    private BookPrice price; //

    public long getBookId(){
        return bookId;
    }

    public void setBookId(long bookId){
