UseServlet.java

@WebServlet("/user.do")
public class UseServlet extends HttpServlet{
    
    private static final long serialVersionUID = 1L;
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
            double laborage=Double.parseDouble(req.getParameter("laborage"));
            double startPoint = Double.parseDouble(req.getParameter("startpoint"));
            double myTax = this.getTax(laborage-startPoint);//调用计算个人所得税的方法
            req.setAttribute("Tax", myTax);//将值保存在请求中
            req.getRequestDispatcher("success.jsp").forward(req, resp);
        
    }
    
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        doPost(req, resp);
    }
    /*计算个人所得税*/
    public double getTax(double charge){
        double tax=0;
        if(charge<=0){
            tax=0;
        }else if (charge>0&&charge<=500) {
            tax=charge*0.05;
        } else if(charge>500&&charge<=2000){
            tax=charge*0.1-25;
        }
        else if(charge>2000&&charge<=5000){
            tax=charge*0.15-125;
        }
        else if(charge>5000&&charge<=20000){
            tax=charge*0.2-375;
        }
        else if(charge>20000&&charge<=40000){
            tax=charge*0.25-1375;
        }
        else if(charge>40000&&charge<=60000){
            tax=charge*0.30-3375;
        }
        else if(charge>60000&&charge<=80000){
            tax=charge*0.35-6375;
        }
        else if(charge>80000&&charge<=100000){
            tax=charge*0.4-10375;
        }else if (charge>100000) {
            tax=charge*0.45-15375;
        }
        return tax;
    }
}

index.jsp

<form action="user.do" method="post">
        <table align="center">
            <tr>
                <td>收入金额：</td>
                <td><input type="text" name="laborage"/></td>
            </tr>
            <tr>
                <td>起征金额：</td>
                <td><input type="text" name="startpoint" value="2000"/>元</td>
            </tr>
            <tr>
                <td colspan="2" align="center">
                <input type="submit" value="计算"/>
                <input type="reset" value="重置"/>
                </td>
            </tr>
        </table>
    </form>

success.jsp

            <tr>
                <td>您应缴纳的个人所得税为：</td>
                <td><%=request.getAttribute("Tax").toString() %></td>
            <tr>
                <td><a href="index.jsp">【回到主页】</a>
                </td>
            </tr>
    </table>

捕获.PNG