加法计算器

cacul.html

	
    //参数在地址栏不显示
		+
		
	

Add.java

package servlet;
import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class Add extends HttpServlet {
	@Override
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		response.setContentType("text/html");
		PrintWriter out=response.getWriter();		
		out.print("");
		out.print("");
		out.print("");
		out.print("");		
		String p1=request.getParameter("param1");//自定义的servlet，父类必须是httpservlet;
		String p2=request.getParameter("param2");//取得文本框的值，文本框的name
		
		String sum;
		try {
			int pp1 = Integer.parseInt(p1);
			int pp2 = Integer.parseInt(p2);	
//string转int方法，String-->Double:Double.parseDouble（字符串参数）
//固定用法：String--XXX类型：XXX.parseXXX(要转换的字符串）
//八种类型-->String类型：在后面加上""（空字符串）
//唯一不一样的用法：String--char：String.charAt（第几个字符）
			sum = pp1+pp2+"";
		} catch (NumberFormatException e) {
			// TODO Auto-generated catch block
//			e.printStackTrace();
			sum="error,Your number is incorrect, please re-enter it";				
		}		
		out.print(p1+"+"+p2+"="+sum+"
");		
		//out.print(pp1+"+"+pp2+"="+sum);		
		out.print("");
		out.print("");		
	}

	@Override
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		this.doGet(request, response);		
	}	
}

web.xml

  demo0927
  
    index.html
    index.htm
    index.jsp
    default.html
    default.htm
    default.jsp
  
  
    DisplayServlet
    servlet.DisplayServlet
  
  
    DisplayServlet
    /display
  
  
    Add
    servlet.Add
  
  
    Add
    /Add
  

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