代理模式

public interface AbstractPermission
{
    //修改个人信息
    public void modifyUserInfo();
 
    //查看他人信息
    public void lookOthersInfo();
 
    //设置年龄
    public void setAge(int age);
}
 
public class PermissionProxy implements AbstractPermission
{
    private RealPermission permission = new RealPermission();
    private int age = 18;
 
    //修改个人信息
    @Override
    public void modifyUserInfo()
    {
        if (age < 18)
        {
            System.out.println("对不起，不能早恋");
        } else if (age >= 18)
        {
            permission.modifyUserInfo();
        }
    }
 
    //查看他人信息
    @Override
    public void lookOthersInfo()
    {
        if (age < 18)
        {
            System.out.println("对不起，不能早恋");
        } else if (age >= 18)
        {
            permission.lookOthersInfo();
        }
    }
 
    //设置年龄
    @Override
    public void setAge(int age)
    {
        this.age = age;
    }
}
 
public class RealPermission implements AbstractPermission
{
    @Override
    public void modifyUserInfo()
    {
        System.out.println("修改用户信息");
    }
 
    @Override
    public void lookOthersInfo()
    {
        System.out.println("查看他人信息");
    }
 
    @Override
    public void setAge(int age)
    {
 
    }
}
 
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
 
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import java.io.File;
 
public class XMLUtil
{
    public static Object getBean()
    {
        try
        {
            //创建DOM文档对象
            DocumentBuilderFactory dFactory = DocumentBuilderFactory.newInstance();
            DocumentBuilder builder = dFactory.newDocumentBuilder();
            Document doc = builder.parse(new File("src/main/resources/config14.xml"));
 
            //获取包含类名的文本节点
            NodeList nl = doc.getElementsByTagName("className");
            Node classNode = nl.item(0).getFirstChild();
            String cName = classNode.getNodeValue();
 
            //通过类名生成实例对象并将其返回
            Class c = Class.forName(cName);
            Object obj = c.newInstance();
            return obj;
        }
        catch (Exception e)
        {
            e.printStackTrace();
            return null;
        }
    }
}
 
public class Client
{
    public static void main(String[] args)
    {
        AbstractPermission permission = (AbstractPermission) XMLUtil.getBean();
 
        permission.modifyUserInfo();
        permission.lookOthersInfo();
        System.out.println("--------------");
        permission.setAge(15);
        permission.modifyUserInfo();
        permission.lookOthersInfo();
    }
}