Java 数据表映射

一对多映射

class Province {    //每一个类就相当于数据库中的一个表；
    private int pid ; 
    private String name ; 
    private City cities [] ;  //一对多

    //setter getter 无参构造 略~

    public Province(int pid , String name) {
        this.pid = pid ; 
        this.name = name ; 
    }

    public void setCities(City cities[]) {
        this.cities = cities ; 
    }

    public City[] getCities() {
        return this.cities ; 
    }

    public String getInfo() {
        return "省份编号：" + this.pid + ", 名称：" + this.name ;
    }
}

class City {
    private int cid ; 
    private String name ; 
    private Province province ; //省份对象元素

    public City(int cid , String name) {
        this.cid = cid ; 
        this.name = name ; 
    }

    public void setProvince(Province province) {
        this.province = province ; 
    }

    public Province getProvince() {
        return this.province; 
    }

    public String getInfo() {
        return "城市编号：" + this.cid + ", 名称：" + this.name ; 
    }
}
/*
    每一个实例化的对象都是单独的个体的存在，占用的是独立的内存空间
    所以每一个实例对象的操作不影响其它实例对象或者类的数据
*/

public class TestPC {
    public static void main(String args[]) {
        // 设置关系数据
        Province pro = new Province(1,"江苏省") ; // 声明Province类对象
        City c1 = new City(1001,"南京市") ; 
        City c2 = new City(1002,"苏州市") ; 
        City c3 = new City(1003,"宿迁市") ; // 什么多个City类对象

        //设置关系
        c1.setProvince(pro) ;    // 利用City实例对象c1调用setProvince()方法并将pro对象传递
        c2.setProvince(pro) ;    // 这就是所谓的 "引用传递"
        c3.setProvince(pro) ; 
        pro.setCities(new City[] {c1,c2,c3}) ; // 调用setCities方法，传入的是数组

        //
        System.out.println(c2.getProvince().getInfo()) ;
        for ( int x = 0 ; x < pro.getCities().length ; x++ ) {
            System.out.println("	" + pro.getCities()[x].getInfo()) ;
        }

    }
}

一对多对多映射

class Item {    // 父栏目
    private int iid ; 
    private String name ; 
    private String note ; 
    //设置简单的表和表（类-类）的关联
    private Subitem subitems [] ;  // 一对多
    private Product products [] ;  // 一对多
    //构建简答Java类-构造
    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 Subitem [] getSubitems() {
        return this.subitems ;
    }

    public void setProducts(Product products[]) {
        this.products = products ; 
    }

    public Product [] getProducts() {
        return this.products ; 
    }

    public String getInfo() {
        return "栏目名称：" + 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 ; 
    private Product products [] ;  //存放的是Product类的实例对象元素
        
    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 void setProducts(Product products []) {
        this.products = products ; 
    }

    public Item getItem() {
        return this.item ; 
    }

    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 subitems ;
    
    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 item ; 
    }

    public void setSubitems(Subitem Subitems) {
        this.subitems = subitems ; 
    }

    public Subitem getSubitems(Subitem subitems) {
        return this.subitems ; 
    }
    
    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[]) {
        // 第一步；设置数据
            // 设置单独的类实例对象
        Item item = new Item (1,"图书","---") ; //  总类

        Subitem suba = new Subitem(1001,"科技类","--") ;// 二分类
        Subitem subb = new Subitem(1002,"文学类","--") ;
        Subitem subc = new Subitem(1003,"图画类","--") ;

        Product proa = new Product(1001001,"物种起源",98.9) ;    //商品
        Product prob = new Product(1001002,"宇宙探索",120.0) ;
        Product proc = new Product(1001003,"魔法奥秘",29.9) ;
        Product prod = new Product(1002001,"知识",19.9) ;
        Product proe = new Product(1002002,"道德经",89.8) ;
        Product prof = new Product(1003001,"365夜故事",9.9) ;
        Product prog = new Product(1003002,"童话公主",9.9) ;
        //设置引用关系
        suba.setItem(item) ;    // 设置Subitem类的多对一的属性
        subb.setItem(item) ;
        subc.setItem(item) ;

        proa.setItem(item) ;
        prob.setItem(item) ;
        proc.setItem(item) ;
        prod.setItem(item) ;
        proe.setItem(item) ;
        prof.setItem(item) ;
        prog.setItem(item) ;

        proa.setSubitems(suba) ;
        prob.setSubitems(suba) ;
        proc.setSubitems(suba) ;
        prod.setSubitems(subb) ;
        proe.setSubitems(subb) ;
        prof.setSubitems(subc) ;
        prog.setSubitems(subc) ;

        suba.setProducts(new Product[] {proa,prob,proc} ) ; // 一个分类对应多个商品
        subb.setProducts(new Product[] {prod,proe}) ; 
        subc.setProducts(new Product[] {prof,prog}) ;

        item.setSubitems(new Subitem[] {suba,subb,subc}) ; //一个总类对应多个分类
        item.setProducts(new Product[] {proa,prob,proc,prod,proe,prof,prog}) ; //一个总类对应多个商品

        //取出数据

        //通过一个类型，找到对应的全部子类型
        System.out.println(item.getInfo()) ; //显示总类
        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.getSubitems().length ; x++ ) { //根据总类 显示子类型
            System.out.println("	-->" + item.getSubitems()[x] .getInfo()) ; //子类型
            for ( int y = 0 ; y < item.getSubitems()[x].getProducts().length ; y++ ) { //根据子类型，查看子类型下的商品
                System.out.println("		-->" + item.getSubitems()[x].getProducts()[y].getInfo()) ;    //商品
            }
        }
    }
}

/*
    程序中，定义的类属性成员的目的是，再调用成员时候，进行的是对象的引用传递    



*/

多对多映射

class Admin {
    private String aid ; 
    private String password ; 
    private Role roles ; 

    public Admin(String aid , String password ) {
        this.aid = aid ; 
        this.password = password ; 
    }

    public void setRoles(Role roles) {
        this.roles = roles ; 
    }

    public Role getRoles() {
        return roles ; 
    }

    public String getInfo() {
        return "管理员ID：" + this.aid + "	 密码：" + this.password ; 
    }
}

class Role {
    private int rid ; 
    private String title ; 
    private Admin admins [] ; 
    private Group groups [] ;

    public Role (int rid , String title ) {
        this.rid = rid ; 
        this.title = title ; 
    }

    public void setAdmins(Admin [] admins) {
        this.admins = admins ; 
    }

    public Admin [] getAdmins() { 
        return admins ; 
    }

    public void setGroups (Group [] groups) {
        this.groups = groups ;
    }

    public Group [] getGroups () {
        return groups ; 
    }

    
    public String getInfo() {
        return "角色ID：" + this.rid + "，角色名称：" + this.title ; 
    }
    
}

class Group {
    private int gid ; 
    private String title ; 
    private Role roles [] ; //一个Group对应多个Role
    private Action actions [] ; //一个Group对应多个Action


    public Group(int gid , String title ) {
        this.gid = gid ; 
        this.title = title ; 
    }

    public void setRoles(Role [] roles) {
        this.roles = roles ; 
    }

    public Role [] getRoles() {
        return roles ; 
    }

    public void setActions (Action [] actions) {
        this.actions = actions ; 
    }

    public Action [] getActions () {
        return actions ; 
    }
    
    public String getInfo() {
        return "权限组ID：" + this.gid + "，权限组名称：" + this.title ; 
    }
}

class Action {
    private int aid ; 
    private String title ; 
    private String url ; 
    private Group groups ; //一个权限对应一个权限组

    public Action (int aid , String title , String url) {
        this.aid = aid ; 
        this.title = title ; 
        this.url = url ; 
    }

    public void setGroups(Group groups) {
        this.groups = groups ; 
    }

    public Group getGroups () {
        return groups ; 
    }
    
    public String getInfo() {
        return "权限ID：" + this.aid + "，权限名称：" + this.title + "，路径：" + this.url ; 
    }

}

//测试
public class TestAdmin {
    public static void main(String args[]) {
        //1 设置完整的映射关系
        // 实例化类对象
        Admin a1 = new Admin("admin" , "hello") ;
        Admin a2 = new Admin("mldn" , "hello") ;
        Admin a3 = new Admin("ayou" , "hello") ;

        Role r1 = new Role(1,"系统管理员") ;
        Role r2 = new Role(2,"信息管理员") ;
        
        Group g1 = new Group(10,"信息管理");
        Group g2 = new Group(11,"用户管理");
        Group g3 = new Group(12,"数据管理");
        Group g4 = new Group(13,"接口管理");
        Group g5 = new Group(14,"备份管理");

        Action ac1 = new Action(1001,"新闻发布","--") ;
        Action ac2 = new Action(1002,"新闻列表","--") ;
        Action ac3 = new Action(1003,"新闻审核","--") ;
        Action ac4 = new Action(1004,"增加用户","--") ;
        Action ac5 = new Action(1005,"用户列表","--") ;
        Action ac6 = new Action(1006,"登录日志","--") ;
        Action ac7 = new Action(1007,"雇员数据","--") ;
        Action ac8 = new Action(1008,"部门数据","--") ;
        Action ac9 = new Action(1009,"公司数据","--") ;
        Action ac10 = new Action(1010,"服务传输","--") ;
        Action ac11 = new Action(1011,"短信平台","--") ;
        Action ac12 = new Action(1012,"全部备份","--") ;
        Action ac13 = new Action(10013,"局部备份","--") ;

        //设置管理员和角色的关系（Admin <> Role）
        a1.setRoles(r1) ;
        a2.setRoles(r2) ;
        a3.setRoles(r2) ; 
        r1.setAdmins(new Admin[] {a1}) ;
        r2.setAdmins(new Admin[] {a2,a3}) ;

        //设置角色和权限组
        r1.setGroups(new Group[] {g1,g2,g3,g4,g5}) ;
        r2.setGroups(new Group[] {g1,g2}) ;
        g1.setRoles(new Role[] {r1,r2});
        g2.setRoles(new Role[] {r1,r2});
        g3.setRoles(new Role[] {r1}) ; 
        g4.setRoles(new Role[] {r1}) ; 
        g5.setRoles(new Role[] {r1}) ; 

        //设置权限组和权限的关系
        g1.setActions(new Action[] {ac1,ac2,ac3});
        g2.setActions(new Action[] {ac4,ac5,ac6});
        g3.setActions(new Action[] {ac7,ac8,ac9});
        g4.setActions(new Action[] {ac10,ac11});
        g5.setActions(new Action[] {ac12,ac13});
        ac1.setGroups(g1) ; 
        ac2.setGroups(g1) ; 
        ac3.setGroups(g1) ; 
        ac4.setGroups(g2) ; 
        ac5.setGroups(g2) ; 
        ac6.setGroups(g2) ; 
        ac7.setGroups(g3) ; 
        ac8.setGroups(g3) ; 
        ac9.setGroups(g3) ; 
        ac10.setGroups(g4) ; 
        ac11.setGroups(g4) ; 
        ac12.setGroups(g5) ; 
        ac13.setGroups(g5) ; 

        //数据读取
        System.out.println("------------------------------------") ;

        System.out.println(a1.getInfo());    //找到一个管理员
        System.out.println("	" + a1.getRoles().getInfo());    //根据挂管理员找到一个角色
        for ( int x = 0 ; x < a1.getRoles().getGroups().length ; x++ ) {//根据角色找到权限组
            System.out.println("	 	" + a1.getRoles().getGroups()[x].getInfo()) ; 
            for ( int y = 0 ; y < a1.getRoles().getGroups()[x].getActions().length ; y++ ) {//根据权限组找权限
                System.out.println("	 	 	" + a1.getRoles().getGroups()[x].getActions()[y].getInfo()) ; 
            }
        }

        System.out.println("------------------------------------") ;

        System.out.println(g2.getInfo()) ; 
        for ( int x = 0 ; x < g2.getRoles().length ; x++ ) {
            System.out.println("	" + g2.getRoles()[x].getInfo()) ; 
            for ( int y = 0 ; y < g2.getRoles()[x].getAdmins().length ; y++ ) {
                System.out.println("		" + g1.getRoles()[x].getAdmins()[y].getInfo()) ; 
            }
        }
    }
}