(六)简单验证和复杂验证

BookServlet.java

package com.aff.bookstore.servlet;

import java.io.IOException;
import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.Map;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.aff.bookstore.domain.Account;
import com.aff.bookstore.domain.Book;
import com.aff.bookstore.domain.ShoppingCart;
import com.aff.bookstore.domain.ShoppingCartItem;
import com.aff.bookstore.domain.User;
import com.aff.bookstore.service.AccountService;
import com.aff.bookstore.service.BookService;
import com.aff.bookstore.service.UserService;
import com.aff.bookstore.web.BookStoreWebUtils;
import com.aff.bookstore.web.CriteriaBook;
import com.aff.bookstore.web.Page;
import com.google.gson.Gson;

@WebServlet("/bookServlet")
public class BookServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        doPost(request, response);
    }

    private BookService bookService = new BookService();

    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String methodName = request.getParameter("method");
        try {
            Method method = getClass().getDeclaredMethod(methodName, HttpServletRequest.class,
                    HttpServletResponse.class);
            method.setAccessible(true);
            method.invoke(this, request, response);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    private UserService userService = new UserService();

    protected void cash(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // 1.简单验证：验证表单域的值是否符合基本的规范：是否为空，是否可以转为int类型，是否是一个email
        // 数据库或调用任何的业务方法

        String username = request.getParameter("username");
        String accountId = request.getParameter("accountId");

        // 表单验证通过
        StringBuffer errors = validateFormField(username, accountId);
        if (errors.toString().equals("")) {// 第一个验证过后验证第二个
            errors = validateUser(username, accountId);

            // 用户名验证通过
            if (errors.toString().equals("")) {// 第二个验证过了再验证第三个
                errors = validateBookStoreNumber(request);

                // 库存验证通过
                if (errors.toString().equals("")) {// 验证第三个

                    // 验证余额是否充足
                    errors = vailidateBalance(request, accountId);

                }
            }
        }

        // error不等于空说明得打印错误信息，则验证没通过
        if (!errors.toString().equals("")) {
            request.setAttribute("errors", errors);
            request.getRequestDispatcher("/WEB-INF/pages/cash.jsp").forward(request, response);
            return;
        }

    }

    private AccountService accountService = new AccountService();

    // 验证余额是否充足
    private StringBuffer vailidateBalance(HttpServletRequest request, String accountId) {
        StringBuffer errors = new StringBuffer("");
        ShoppingCart cart = BookStoreWebUtils.getShoppingCart(request);

        Account account = accountService.getAccount(Integer.parseInt(accountId));
        if (cart.getTotalMoney() > account.getBalance()) {
            errors.append("余额不足");

        }
        return errors;
    }

    // 验证库存是否充足
    private StringBuffer validateBookStoreNumber(HttpServletRequest request) {
        StringBuffer errors = new StringBuffer("");
        ShoppingCart cart = BookStoreWebUtils.getShoppingCart(request);
        for (ShoppingCartItem sci : cart.getItems()) {
            int quantity = sci.getQuantity();

            // 书的库存，获取一个最新的书的库存
            int storeNumber = bookService.getBook(sci.getBook().getId()).getStoreNumber();

            if (quantity > storeNumber) {
                errors.append(sci.getBook().getTitle() + "库存不足<br>");
            }
        }
        return errors;
    }

    // 抽出的验证用户名和账户是否匹配
    private StringBuffer validateUser(String username, String accountId) {
        boolean flag = false;
        User user = userService.getUserByUserName(username);
        if (user != null) {
            int accountId2 = user.getAccountId();
            if (accountId.trim().equals("" + accountId2)) {
                flag = true;

            }
        }
        StringBuffer errors2 = new StringBuffer("");
        if (!flag) {
            errors2.append("用户名和账户不匹配");
        }
        return errors2;
    }

    // 抽出的简单验证,,表单是否符合基本的规则，是否为空
    private StringBuffer validateFormField(String username, String accountId) {
        StringBuffer errors = new StringBuffer();

        if (username == null || username.trim().equals("")) {
            errors.append("用户名不能为空<br>");

        }
        if (accountId == null || accountId.trim().equals("")) {
            errors.append("账户不能为空");
        }
        return errors;
    }

    protected void updateItemQuantity(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        //4. 在 updateItemQuantity 方法中, 获取 quanity, id, 再获取购物车对象, 调用 service 的方法做修改
        System.out.println("============================");
        String idStr = request.getParameter("id");
        String quantityStr = request.getParameter("quantity");
        
        ShoppingCart sc = BookStoreWebUtils.getShoppingCart(request);
        
        int id = -1;
        int quantity = -1;
        
        try {
            id = Integer.parseInt(idStr);
            quantity = Integer.parseInt(quantityStr);
        } catch (Exception e) {}
        
        if(id > 0 && quantity > 0)
            bookService.updateItemQuantity(sc, id, quantity);
        
        //5. 传回 JSON 数据: bookNumber:xx, totalMoney
        Map<String, Object> result = new HashMap<String, Object>();
        result.put("bookNumber", sc.getBookNumber());
        result.put("totalMoney", sc.getTotalMoney());
        
        Gson gson = new Gson();
        String jsonStr = gson.toJson(result);
        response.setContentType("text/javascript");
        response.getWriter().print(jsonStr);
    }

    protected void clear(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        ShoppingCart sc = BookStoreWebUtils.getShoppingCart(request);
        bookService.clearShoppingCart(sc);
        request.getRequestDispatcher("/WEB-INF/pages/empty.jsp").forward(request, response);
    }

    // 删除商品
    protected void remove(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String idStr = request.getParameter("id");
        int id = -1;
        try {
            id = Integer.parseInt(idStr);
        } catch (Exception e) {
        }
        ShoppingCart sc = BookStoreWebUtils.getShoppingCart(request);
        bookService.removeItemFromShoppingCart(sc, id);
        if (sc.isEmpty()) {
            request.getRequestDispatcher("/WEB-INF/pages/empty.jsp").forward(request, response);
        }

        // 删除完再转发为回来
        request.getRequestDispatcher("/WEB-INF/pages/cart.jsp").forward(request, response);

    }

    protected void forwardPage(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String page = request.getParameter("page");
        request.getRequestDispatcher("/WEB-INF/pages/" + page + ".jsp").forward(request, response);
    }

    protected void addToCart(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        // 1.获取商品的id
        String idStr = request.getParameter("id");
        int id = -1;
        boolean flag = false;

        try {
            id = Integer.parseInt(idStr);
        } catch (Exception e) {
        }

        if (id > 0) {
            // 2.获取购物差对象
            ShoppingCart sc = BookStoreWebUtils.getShoppingCart(request);

            // 3.调用 BookService 的addToCart() 方法 把商品放到购物车中
            flag = bookService.addToCart(id, sc);
        }

        if (flag) {
            // 4.直接调用 getBooks()方法
            getBooks(request, response);
            return;
        }
        response.sendRedirect(request.getContextPath() + "/errror-1.jsp");
    }

    protected void getBook(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String idStr = request.getParameter("id");
        int id = -1;
        Book book = null;

        try {
            id = Integer.parseInt(idStr);
        } catch (NumberFormatException e) {
        }

        if (id > 0) {
            book = bookService.getBook(id);
            if (book == null) {
                response.sendRedirect(request.getContextPath() + "/errror-1.jsp");
                return;
            }
        }
        request.setAttribute("book", book);
        request.getRequestDispatcher("/WEB-INF/pages/book.jsp").forward(request, response);
    }

    protected void getBooks(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        String pageNoStr = request.getParameter("pageNo");
        String minPriceStr = request.getParameter("minPrice");
        String maxPriceStr = request.getParameter("maxPrice");

        int pageNo = 1;
        int minPrice = 0;
        int maxPrice = Integer.MAX_VALUE;
        try {
            pageNo = Integer.parseInt(pageNoStr);
        } catch (Exception e) {
        }
        try {
            minPrice = Integer.parseInt(minPriceStr);
        } catch (Exception e) {
        }
        try {
            maxPrice = Integer.parseInt(maxPriceStr);
        } catch (Exception e) {
        }
        CriteriaBook criteriaBook = new CriteriaBook(minPrice, maxPrice, pageNo);
        Page<Book> page = bookService.getPage(criteriaBook);

        request.setAttribute("bookpage", page);
        request.getRequestDispatcher("/WEB-INF/pages/books.jsp").forward(request, response);

    }

}

cash.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@taglib prefix="c"  uri="http://java.sun.com/jsp/jstl/core"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
            <center>
                    <br><br>
                    您一共买了 ${sessionScope.ShoppingCart.bookNumber} 本书
                    <br><br>
                    应付：￥${sessionScope.ShoppingCart.totalMoney}
                    <br><br>
                    
                    <c:if test="${requestScope.errors !=null }">
                    <font color="red">${requestScope.errors }</font>
                    
                    
                    </c:if>
                    
            
            <form action="bookServlet?method=cash" method="post">
            <table cellpadding="10">
                    <tr>
                            <td>信用卡姓名</td>
                            <td><input type="text" name="username"/></td>
                    </tr>
                    <tr>
                            <td>信用卡账号</td>
                            <td><input type="text" name="accountId"/></td>
                    </tr>
                    <tr>
                            <td colspan="2"><input type="submit" value="Submit"/></td>
                    </tr>
            </table>
            
            </form>
            </center>
            
</body>
</html>

效果如下