在进行项目实际开发过程之中，对于用户的授权管理是一项重要的任务，下面给出了一个最为常见的用户权限管理的表结构设计，基本的关系如下：

• 一个用户可以拥有多个角色，一个角色可能有多个用户；

• 一个角色可以拥有多个权限；

    要求实现如下查询功能：

• 可以根据一个用户找到该用户对应的所有角色，以及每一个角色对应的所有权限信息；

• 可以根据一个角色找到该角色下的所有权限，以及拥有此角色的全部用户信息；

• 可以根据一个权限找到具备有此权限的所有用户信息。

class Member{
    private String mid;
    private String name;
    private Role roles []; //多个角色
    public Member(String mid,String name){
        this.mid = mid;
        this.name = name;
    }
    // setter、getter、无参构造略
    public void setRoles(Role roles[]){
        this.roles = roles;
    }
    public Role[] getRoles(){
        return this.roles;
    }
    public String getInfo(){
        return "【用户信息】mid = " + this.mid + "、name = " + this.name;
    }
}
class Role{
    private long rid;
    private String title;
    private Member members[];
    private Privilege privileges[];
    public Role(long rid,String title){
        this.rid = rid;
        this.title = title;
    }
    public void setMember(Member members[]){
        this.members = members;
    }
    public void setPrivilege(Privilege privileges[]){
        this.privileges = privileges;
    }
    public Member[] getMember(){
        return this.members;
    }
    public Privilege[] getPrivileges(){
        return this.privileges;
    }
    //  setter、getter、无参构造略
    public String getInfo(){
        return "【角色信息】rid = " + this.rid + "title = " + this.title;
    }
}
class Privilege{
    private long pid;
    private String title;
    private Role role;
    public Privilege(long pid,String title){
        this.pid = pid;
        this.title = title;
    }
    public void setRole(Role role){
        this.role = role;
    }
    public Role getRole(){
        return this.role;
    }
    public String getInfo(){
        return "【权限信息】pid = " + this.pid + "、title = " + this.title;
    }
}
public class JavaDemo{
    public static void main(String args[]){
        //第一步：根据结构设置对象数据
        Member memA = new Member("mldn-a","张三");
        Member memB = new Member("mldn-b","李四");
        Role roleA = new Role(1L,"系统配置");
        Role roleB = new Role(2L,"备份管理");
        Role roleC = new Role(3L,"人事管理");
        Privilege priA = new Privilege(1000L,"系统初始化");
        Privilege priB = new Privilege(1001L,"系统还原");
        Privilege priC = new Privilege(1002L,"系统环境修改");
        Privilege priD = new Privilege(2000L,"备份员工数据");
        Privilege priE = new Privilege(2001L,"备份部门数据");
        Privilege priF = new Privilege(2002L,"备份公文数据");
        Privilege priG = new Privilege(3000L,"增加员工");
        Privilege priH = new Privilege(3001L,"编辑员工");
        Privilege priI = new Privilege(3002L,"浏览员工");
        Privilege priJ = new Privilege(3003L,"员工离职");
        //增加角色与权限的对应关系
        roleA.setPrivilege(new Privilege[]{priA,priB,priC});
        roleB.setPrivilege(new Privilege[]{priD,priE,priF});
        roleC.setPrivilege(new Privilege[]{priG,priH,priI,priJ});
        // 增加权限与角色对应
        priA.setRole(roleA);
        priB.setRole(roleA);
        priC.setRole(roleA);
        priD.setRole(roleB);
        priE.setRole(roleB);
        priF.setRole(roleB);
        priG.setRole(roleC);
        priH.setRole(roleC);
        priI.setRole(roleC);
        priJ.setRole(roleC);
        // 增加用户与角色的对应关系
        memA.setRoles(new Role[] {roleA,roleB});
        memB.setRoles(new Role[] {roleA,roleB,roleC});
        roleA.setMember(new Member[]{memA,memB});
        roleB.setMember(new Member[]{memA,memB});
        roleC.setMember(new Member[]{memB});
        //第二步：根据要求获取数据
        System.out.println("------ 通过用户查找信息 ------");
        System.out.println(memB.getInfo());
        for(int x = 0; x < memB.getRoles().length; x++){
            System.out.println("\t|- " + memB.getRoles()[x].getInfo());
            for(int y = 0; y < memB.getRoles()[x].getPrivileges().length; y++){
                System.out.println("\t\t|- " + memB.getRoles()[x].getPrivileges()[y].getInfo());
            }
        }
        System.out.println("------ 通过角色查找信息 ------");
        System.out.println(roleB.getInfo());
        System.out.println("\t|- 浏览此角色下的所有权限信息:");
        for(int x = 0; x < roleB.getPrivileges().length; x++){
            System.out.println("\t\t|- " + roleB.getPrivileges()[x].getInfo());
        }
        System.out.println("\t|- 浏览此角色下的所有用户信息:");
        for(int x = 0 ; x < roleB.getMember().length;x++){
            System.out.println("\t\t|- " + roleB.getMember()[x].getInfo());
        }
        System.out.println("------ 通过权限查找信息 ------");
        System.out.println(priA.getInfo());
        for(int x = 0; x < priA.getRole().getMember().length; x++){
            System.out.println("\t|- " + priA.getRole().getMember()[x].getInfo());
        }
    }   
}