Java简单类——双向一对多映射

class Item {     // 父栏目
    private int iid ;
    private String name ;
    private String note ;
    private Subitem subitems [] ; //一个父栏目下有多个子栏目
    private Product products [] ; //一个栏目下包含多个商品
    public Item(int iid,String name,String note) {
        this.iid = iid ;
        this.name = name ;
        this.note = note ;
    }
    public void setSubitems(Subitem subitems[]) {
        this.subitems = subitems ;
    }
    public void setProducts(Product[] products) {
        this.products = products ;
    }
    public Product[] getProducts() {
        return this.products ;
    }
    public Subitem [] getSubitems() {
        return this.subitems ;
    }
    public String getInfo() {
        return "栏目编号：" + this.iid + "，名称：" + this.name + "，描述：" + this.note ;
    }
}
class Subitem {  // 子栏目
    private int sid ;
    private String name ;
    private String note ;
    private Item item ; // 一个子栏目对应一个父栏目
    private Product products [] ; //一个子栏目下包含多个商品
    public Subitem(int sid,String name,String note) {
        this.sid = sid ;
        this.name = name ;
        this.note = note ;
    }
    public void setItem(Item item) {
        this.item = item ;
    }
    public Item getItem() {
        return this.item ;
    }
    public void setProducts(Product products[]) {
        this.products = products ;
    }
    public Product[] getProducts() {
        return this.products ;
    }
    public String getInfo() {
        return "子栏目编号：" + this.sid + "，名称：" + this.name + "，描述：" + this.note ;
    }
}
class Product {  // 商品
    private int pid ;
    private String name ;
    private double price ;
    private Item item ;
    private Subitem subitem ;
    public Product(int pid,String name,double price) {
        this.pid = pid ;
        this.name = name ;
        this.price = price ;
    }
    public void setItem(Item item) {
        this.item = item ;
    }
    public Item getItem() {
        return this.item ;
    }
    public void setSubitem(Subitem subitem) {
        this.subitem = subitem ;
    }
    public Subitem getSubitem() {
        return this.subitem ;
    }
    public String getInfo() {
        return "商品编号：" + this.pid + "，名称：" + this.name + "，价格：" + this.price ;
    }
}
public class TestISP {
    public static void main(String args[]){
        //准备出单独的类对象
        Item item = new Item(1,"文具","-") ;
        Subitem suba = new Subitem(1001,"笔","-") ;
        Subitem subb = new Subitem(1002,"尺","-") ;
        Subitem subc = new Subitem(1003,"刀","-") ;
        Product proa = new Product(90001,"中性笔",2.0) ;
        Product prob = new Product(90002,"钢笔",10.0) ;
        Product proc = new Product(90003,"毛笔",8.0) ;
        Product prod = new Product(90004,"直尺",2.0) ;
        Product proe = new Product(90005,"三角尺",1.5) ;
        Product prof = new Product(90006,"美工刀",5.0) ;
        Product prog = new Product(90007,"剪刀",6.0) ;
        //设置类之间的引用关系
        suba.setItem(item) ;
        subb.setItem(item) ;
        subc.setItem(item) ;
        item.setSubitems(new Subitem[]{suba,subb,subc}) ;
        proa.setSubitem(suba) ;
        proa.setItem(item) ;
        prob.setSubitem(suba) ;
        prob.setItem(item) ;
        proc.setSubitem(suba) ;
        proc.setItem(item) ;
        prod.setSubitem(subb) ;
        prod.setItem(item) ;
        proe.setSubitem(subb) ;
        proe.setItem(item) ;
        prof.setSubitem(subc) ;
        prof.setItem(item) ;
        prog.setSubitem(subc) ;
        prog.setItem(item) ;
        suba.setProducts(new Product[] {proa,prob,proc}) ;
        subb.setProducts(new Product[] {prod,proe}) ;
        subc.setProducts(new Product[] {prof,prog}) ;
        item.setProducts(new Product[] {proa,prob,proc,prod,proe,prof,prog}) ;
        //取出数据
        //1、通过一个类型找到全部的子类型
        System.out.println(item.getInfo()) ;
        for (int x = 0;x <item.getSubitems().length ;x ++ ){
            System.out.println("	|-" + item.getSubitems()[x].getInfo()) ;
        }
        System.out.println("--------------------------------------------------------------") ;
        System.out.println(item.getInfo()) ;
        for (int x = 0;x <item.getProducts().length ;x ++ ){
            System.out.println("	|-" + item.getProducts()[x].getInfo()) ;
            System.out.println("	|-" + item.getProducts()[x].getSubitem().getInfo()) ;
        }            
        System.out.println("--------------------------------------------------------------") ;
        System.out.println(subb.getInfo()) ;
        for (int x = 0;x <subb.getProducts().length ;x ++ ){
            System.out.println("	|-" + subb.getProducts()[x].getInfo()) ;
        }
    }
}

第一次写上百行的代码啊QAQ，中间报错了几次折腾了好久才发现是尼玛设定set和get方法时竟然不知道怎么的把public写成了private，晕死，以后就知道了。错误如下图

最终完成时运行结果如下