1.创建名为ComputeBill的servlet文件
2.重写init()和service()
package myservlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class ComputeBill
*/
@WebServlet("/ComputeBill")
public class ComputeBill extends HttpServlet {
private static final long serialVersionUID = 1L;
public ComputeBill() {
super();
// TODO Auto-generated constructor stub
}
public void init(ServletConfig config) throws ServletException {
super.init(config);
}
protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1.设置编码格式
request.setCharacterEncoding("UTF-8");
response.setContentType("text/html;charset=UTF-8");
//2.用printWriter类输出流声明out对象，通过response对象调用getWriter()方法获取一个输出流，利用out对象调用println()方法输出html标记，将背景色设为蓝色
PrintWriter out = response.getWriter();
out.println("<html><body bgcolor=lightblue>");
//3.通过request对象获取表单中名字叫billMess的文本区中的内容并送给字符串str
String str = request.getParameter("billMess");
//4.如果str为空，则service方法结束，否则利用split()方法，其参数为正则表达式，将数字分解后送到字符串数组price中
if(str == null||str.length() == 0)
return;
String []price = str.split("[^0123456789.]+");
//5.求和要定义变量sum初值为0，利用循环遍历数组，求出数组中存储的数字的和
double sum = 0;
try {
for(int i=0;i<price.length;i++) {
if(price[i].length()>=1) {
sum+=Double.parseDouble(price[i]);
}
}
}
catch(NumberFormatException e){
out.print(""+e);
}
//6.利用out对象的方法输出消费总额，及HTML标记
out.print("\""+ str +"\"<br>的消费额："+sum+"元");
out.println("</body></html>");
}
}
3.配置web.xml
4.创建sevletdemo2.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>使用表单给servlet送数据</title>
</head>
<body>
<form action="computeBill" method="post" >
输入账单：<br>
<textarea rows="5" cols="30" name="billMess">
洗衣粉：12.8元
可乐：12元
泡菜：2.8元
</textarea>
<br>
<input type="submit" name="提交" />
</form>
</body>
</html>5.运行
点击提交按钮
