Java简单类——双向一对多映射
1 class Item { // 父栏目 2 private int iid ; 3 private String name ; 4 private String note ; 5 private Subitem subitems [] ; //一个父栏目下有多个子栏目 6 private Product products [] ; //一个栏目下包含多个商品 7 public Item(int iid,String name,String note) { 8 this.iid = iid ; 9 this.name = name ; 10 this.note = note ; 11 } 12 public void setSubitems(Subitem subitems[]) { 13 this.subitems = subitems ; 14 } 15 public void setProducts(Product[] products) { 16 this.products = products ; 17 } 18 public Product[] getProducts() { 19 return this.products ; 20 } 21 public Subitem [] getSubitems() { 22 return this.subitems ; 23 } 24 public String getInfo() { 25 return "栏目编号：" + this.iid + "，名称：" + this.name + "，描述：" + this.note ; 26 } 27 } 28 class Subitem { // 子栏目 29 private int sid ; 30 private String name ; 31 private String note ; 32 private Item item ; // 一个子栏目对应一个父栏目 33 private Product products [] ; //一个子栏目下包含多个商品 34 public Subitem(int sid,String name,String note) { 35 this.sid = sid ; 36 this.name = name ; 37 this.note = note ; 38 } 39 public void setItem(Item item) { 40 this.item = item ; 41 } 42 public Item getItem() { 43 return this.item ; 44 } 45 public void setProducts(Product products[]) { 46 this.products = products ; 47 } 48 public Product[] getProducts() { 49 return this.products ; 50 } 51 public String getInfo() { 52 return "子栏目编号：" + this.sid + "，名称：" + this.name + "，描述：" + this.note ; 53 } 54 } 55 class Product { // 商品 56 private int pid ; 57 private String name ; 58 private double price ; 59 private Item item ; 60 private Subitem subitem ; 61 public Product(int pid,String name,double price) { 62 this.pid = pid ; 63 this.name = name ; 64 this.price = price ; 65 } 66 public void setItem(Item item) { 67 this.item = item ; 68 } 69 public Item getItem() { 70 return this.item ; 71 } 72 public void setSubitem(Subitem subitem) { 73 this.subitem = subitem ; 74 } 75 public Subitem getSubitem() { 76 return this.subitem ; 77 } 78 public String getInfo() { 79 return "商品编号：" + this.pid + "，名称：" + this.name + "，价格：" + this.price ; 80 } 81 } 82 public class TestISP { 83 public static void main(String args[]){ 84 //准备出单独的类对象 85 Item item = new Item(1,"文具","-") ; 86 Subitem suba = new Subitem(1001,"笔","-") ; 87 Subitem subb = new Subitem(1002,"尺","-") ; 88 Subitem subc = new Subitem(1003,"刀","-") ; 89 Product proa = new Product(90001,"中性笔",2.0) ; 90 Product prob = new Product(90002,"钢笔",10.0) ; 91 Product proc = new Product(90003,"毛笔",8.0) ; 92 Product prod = new Product(90004,"直尺",2.0) ; 93 Product proe = new Product(90005,"三角尺",1.5) ; 94 Product prof = new Product(90006,"美工刀",5.0) ; 95 Product prog = new Product(90007,"剪刀",6.0) ; 96 //设置类之间的引用关系 97 suba.setItem(item) ; 98 subb.setItem(item) ; 99 subc.setItem(item) ; 100 item.setSubitems(new Subitem[]{suba,subb,subc}) ; 101 proa.setSubitem(suba) ; 102 proa.setItem(item) ; 103 prob.setSubitem(suba) ; 104 prob.setItem(item) ; 105 proc.setSubitem(suba) ; 106 proc.setItem(item) ; 107 prod.setSubitem(subb) ; 108 prod.setItem(item) ; 109 proe.setSubitem(subb) ; 110 proe.setItem(item) ; 111 prof.setSubitem(subc) ; 112 prof.setItem(item) ; 113 prog.setSubitem(subc) ; 114 prog.setItem(item) ; 115 suba.setProducts(new Product[] {proa,prob,proc}) ; 116 subb.setProducts(new Product[] {prod,proe}) ; 117 subc.setProducts(new Product[] {prof,prog}) ; 118 item.setProducts(new Product[] {proa,prob,proc,prod,proe,prof,prog}) ; 119 //取出数据 120 //1、通过一个类型找到全部的子类型 121 System.out.println(item.getInfo()) ; 122 for (int x = 0;x <item.getSubitems().length ;x ++ ){ 123 System.out.println("\t|-" + item.getSubitems()[x].getInfo()) ; 124 } 125 System.out.println("--------------------------------------------------------------") ; 126 System.out.println(item.getInfo()) ; 127 for (int x = 0;x <item.getProducts().length ;x ++ ){ 128 System.out.println("\t|-" + item.getProducts()[x].getInfo()) ; 129 System.out.println("\t|-" + item.getProducts()[x].getSubitem().getInfo()) ; 130 } 131 System.out.println("--------------------------------------------------------------") ; 132 System.out.println(subb.getInfo()) ; 133 for (int x = 0;x <subb.getProducts().length ;x ++ ){ 134 System.out.println("\t|-" + subb.getProducts()[x].getInfo()) ; 135 } 136 } 137 }
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
