javaWeb项目解耦之工厂模式使用

javaWeb项目使用经典三层架构

config.properties 文件配置如图所示

factory代码

import java.io.FileReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.Reader;
import java.util.Properties;

public class BaseFactory {
    private static BaseFactory factory = new BaseFactory();
    private static Properties prop = null;
    private BaseFactory() {
    }
    public static BaseFactory getFactory(){
        return factory;
    }
    
    static{
        try {
            prop = new Properties();
            prop.load(new FileReader(BaseFactory.class.getClassLoader().getResource("config.properties").getPath()));
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        }
    }
    public <T> T getInstance(Class<T> clazz){
        try {
            String cName = clazz.getSimpleName();
            String cImplName = prop.getProperty(cName);
            return (T)Class.forName(cImplName).newInstance();
        } catch (Exception e) {
            e.printStackTrace();
            throw new RuntimeException(e);
        }
        
    }
    
}

service调用dao层 示例代码

 UserDao userDao = BaseFactory.getFactory().getInstance(UserDao.class);