JAVA反射机制web中的应用实例

   首先 我们建立一个用户输入的页面，有两个字段：UserName和PassWord

<form action="./UserServlet">
userName:<input type="text" name="userName"/><br>
passWord:<input type="text" name="passWord"/><br>
<input type="submit" value="login">
</form>

   然后，我们建立字段的Bean类 进行封装  UserBean：

public class UserBean {
    private String userName;
    private String passWord;
    public String getPassWord() {
        return passWord;
    }
    public void setPassWord(String passWord) {
        this.passWord = passWord;
    }
    public String getUserName() {
        return userName;
    }
    public void setUserName(String userName) {
        this.userName = userName;
    }
    
}

 

  再次建立一个工具类 就是应用到的反射的核心代码 Tools.java

import java.lang.reflect.Field;
import java.lang.reflect.Method;

import javax.servlet.http.HttpServletRequest;

public class Tools {
    public static Object initBean(HttpServletRequest request,Class cls)
    {
        Object obj = null;
        try {
            obj = cls.newInstance();
            
            Field[] fields = cls.getDeclaredFields();
            
            for (Field field : fields) {
                String fieldName = field.getName();
                
                Method method = cls.getDeclaredMethod("set"+fieldName.substring(0,1).toUpperCase()+fieldName.substring(1), new Class[]{String.class});
                String value = request.getParameter(fieldName);    
                method.invoke(obj, new Object[]{value});
            }
            
        } catch (Exception e) {
            // TODO Auto-generated catch block

            e.printStackTrace();
        }
        return obj;
    }
    
    public static void main(String[] args) throws Exception {
        Class cls = Class.forName("com.accp.UserBean");//根据类名来得到一个Class对象

        Class c = UserBean.class;//根据类来得到一个Class对象

        Object o = cls.newInstance();//通过类得到一个实例对象 UserBean bean = new UserBean();

    }
}

最后 建立页面提交到的Servlet UserServlet：

 

public void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        UserBean bean = (UserBean)Tools.initBean(request, UserBean.class);
        System.out.println(bean.getUserName()+" "+bean.getPassWord());
    }

 

这样就实现了 运用反射 动态获取数据的效果