1.创建Book封装图书信息：Book

public class Book {
    private String id;
    private String name;

    public Book(String id, String name) {
        this.id = id;
        this.name = name;
    }

    public Book() {
    }

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

2.创建BookDB,模拟数据库，里面保存图书

public class BookDB {
    private static Map<String ,Book> map = new LinkedHashMap<String, Book>();
    static {
        map.put("1",new Book("1","java web"));
        map.put("2",new Book("2","jdbc"));
        map.put("3",new Book("3","java 基础"));
        map.put("4",new Book("4","struts框架"));
        map.put("5",new Book("5