BaseServlet扩展了的HttpServlet，来实现减少Servlet数量

来源：互联网发布：三线表格及数据分析编辑：程序博客网时间：2024/04/30 10:32

调用顺序：

1.BaseServlet类

package czb.utils;
 
import java.io.IOException;
import java.lang.reflect.Method;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
 
// 扩展Httpservlet用户请求某个servlet的url为：/PersonServlet?metd=save
public abstract classBaseServlet extends HttpServlet {
    private static final longserialVersionUID= 1L;
 
    @Override
    public void service(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException,IOException {
        req.setCharacterEncoding("UTF-8");
        // 获取参数
        String metd = req.getParameter("metd");
        if (metd == null || metd.trim().equals("")) {
            metd= "execute";
        }
        try {
            // 通过反射去调子类的方法，获取实现类的方法反射save(req,reps)
            Method method = this.getClass().getMethod(metd, //this是指实现类的实例对象
                   HttpServletRequest.class, HttpServletResponse.class);
            // 调用的实现类的方法
            method.invoke(this, req, resp);
        }catch(Exception e) {
            thrownew RuntimeException(e);
        }
    }
 
    public void execute(HttpServletRequest req, HttpServletResponse resp)
            throws Exception {
        resp.sendError(406,"至少重写一个默认的方法、、、、、");
    }
}

2.BaseServlet的实现类

package czb.servlet;
 
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import czb.utils.BaseServlet;
 
public class PersonServlet extends BaseServlet {
    private static final longserialVersionUID= 1L;
 
    public void save(HttpServletRequestreq, HttpServletResponse resp)
            throws Exception {
        String name = req.getParameter("name");
        System.err.println("你的姓名是：" + name + ",你在操作保存。。");
    }
 
    public void del(HttpServletRequestreq, HttpServletResponse resp)
            throws Exception {
        System.err.println("你在操作删除。。");
    }
 
    public voidupdate(HttpServletRequest req, HttpServletResponse resp)
            throws Exception {
        String name = req.getParameter("name");
        System.err.println("你的姓名是：" + name + ",你在操作更新。。");
    }
 
}

3.测试

<body>
   <form action="<c:url value='/PersonServlet?metd=save'/>"method="post">
       <input type="text"name="name"><br/>
       <input type="submit"><br/>
   </form>
   <a href="<c:url value='/PersonServlet?metd=del'/>">查询</a>
   <hr/>
    <form action="PersonServlet" method="post">
     Name:<input type="text" name="name"id="nm">
     <input type="submit" value="删除">
  </form>
  <br/>
  <a href="javascript:_go();">GO</a>
</body>
<script type="text/javascript">
 function_go(){
      var nm=document.getElementById("nm").value;
      var rul = "StudServlet?metd="+nm;
      //对url进行编码
      url=encodeURI(url);
      window.location=url;
 }
 
</script>