JavaWeb--MVC案例1-------（3）模糊查找
1.index.jsp
1.获取 request 中的 customers 属性
2.遍历显示
<%@ page import="MVCCases.Customer" %>
<%@ page import="java.util.List" %><%--
Created by IntelliJ IDEA.
User: Skye
Date: 2017/12/8
Time: 9:45
To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>$Title$</title>
</head>
<body>
<form action="query.do", method="post ">
<table>
<tr>
<td>Name:</td>
<td><input type="text", name="name"/></td>
</tr>
<tr>
<td>Address:</td>
<td><input type="text", name="address"/></td>
</tr>
<tr>
<td>Phone:</td>
<td><input type="text", name="phone"</td>
</tr>
<tr>
<td><input type="submit", value="Query"/></td>
<td><a href="">Create New Customer</a></td>
</tr>
</table>
</form>
<br><br>
<%
List<Customer> customers = (List<Customer>)request.getAttribute("customers");
if(customers != null && customers.size() != 0){
%>
<br><br>
<hr>
<table border="1" cellpadding="10" cellspacing="0">
<tr><%--tr表示行，td表示列，th表示表头--%>
<th>ID</th>
<th>NAME</th>
<th>Address</th>
<th>Phone</th>
<th>Delete/Update</th>
</tr>
<%
for(Customer customer: customers){
%>
<tr>
<td><%= customer.getId()%></td>
<td><%= customer.getName()%></td>
<td><%= customer.getAddress()%></td>
<td><%= customer.getPhone()%></td>
<td>
<a href="">UPDATE</a>
<a href="">DELETE</a>
</td>
</tr>
<%
}
%>
</table>
<%
}
%>
</body>
</html>
查询操作：
1.Servlet
//1. 调用 CustomerDAO 的 getAll() 得到 Customer 的集合
List<Customer> customers = customerDAO.getAll();
//2. 把 Customer 的集合放入 request 中
request.setAttribute("customers", customers);
//3. 转发页面到 index.jsp(不能使用重定向)
request.getRequestDispatcher("/index.jsp").forward(request, response);
2.JSP
获取 request 中的 customers 属性
遍历显示
模糊查询
根据传入的 name, address, phone 进行模糊查询
例子: name: a、address: b、phone: 3 则 SQL 语句的样子为: SELECT id, name, address, phone FROM customers WHERE name LIKE ‘%a%’ AND address LIKE ‘%b%’ AND phone LIKE ‘%3%’
需要在 CustomerDAO 接口中定义一个 getForListWithCriteriaCustomer(CriteriaCustomer cc)。 其中 CriteriaCustomer 用于封装查询条件：name, address, phone。因为查询条件很多时候和 domain 类并不相同，所以要做成一个单独的类
拼 SQL：
SQL: "SELECT id, name, address, phone FROM customers WHERE " +
"name LIKE ? AND address LIKE ? ANDphone LIKE ?";
为了正确的填充占位符时，重写了 CriteriaCustomer 的 getter：
修改 Servlet：获取请求参数；把请求参数封装为
CriteriaCustomer 对象，再调用 getForListWithCriteriaCustomer(CriteriaCustomer cc) 方法
CriteriaCustomer 中
package MVCCases;
public class CriteriaCustomer {
private String name;
private String address;
private String phone;
public String getName() {
if(name == null){
name = "%%";
}else{
name = "%" + name + "%";
}
return name;
}
public void setName(String name) {
this.name = name;
}
public String getAddress() {
if(address == null){
address = "%%";
}else{
address = "%" + address + "%";
}
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String getPhone() {
if(phone == null){
phone = "%%";
}else{
phone = "%" + phone + "%";
}
return phone;
}
public void setPhone(String phone) {
this.phone = phone;
}
public CriteriaCustomer(String name, String address, String phone) {
this.name = name;
this.address = address;
this.phone = phone;
}
}
CustomerDAO中
/**
* 返回满足查询条件的List
* @param cc：封装了查询条件
* @return
*/
public List<Customer> getForListWithCriteriaCustomer(CriteriaCustomer cc);
CustomerDAOImpl中
@Override
public List<Customer> getForListWithCriteriaCustomer(CriteriaCustomer cc) {
String sql = "SELECT id, name, address, phone FROM customer WHERE " +
"name LIKE ? AND address LIKE ? AND phone LIKE ?";
//修改了CriteriaCustomer的getter()方法，使其返回字符串中有%%（模糊查询）
//若返回值为null，则返回“%%”， 否则返回"%" + value + "%"
return getForList(sql, cc.getName(), cc.getAddress(), cc.getPhone());
}
CustomerServ中的转发与查询
package MVCCases;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.lang.reflect.Method;
import java.util.List;
public class CustomerServlet extends HttpServlet {
private CustomerDAO customerDAO = new CustomerDAOImpl();
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
//super.doGet(req, resp);
doPost(req, resp);
}
@Override
protected void doPost(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
//super.doPost(req, resp);
//1.获取servletPath：/add.do 或 /delete.do等
String servletPath = req.getServletPath();
//2.取出/和.do得到方法名
String methodName = servletPath.substring(1);
methodName = methodName.substring(0, methodName.length() - 3);
//3.利用反射获取methodName对应的方法
Method method = null;
try {
method = getClass().getDeclaredMethod(methodName,
HttpServletRequest.class, HttpServletResponse.class);
//4.利用发射调用对应的方法
method.invoke(this, req, resp);
} catch (Exception e) {
e.printStackTrace();
resp.sendRedirect("error.jsp");
}
}
private void add(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
System.out.println("add");
}
private void query(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
//获取模糊查询的请求参数
String name = req.getParameter("name");
String address = req.getParameter("address");
String phone = req.getParameter("phone");
//把请求参数封装为一个CriteriaCustomer对象
CriteriaCustomer cc = new CriteriaCustomer(name, address, phone);
//1.调用CustomerDAOImpl类的getForListWithCriteriaCustomer方法
List<Customer> customers = customerDAO.getForListWithCriteriaCustomer(cc);
//2.把customers放入req中
req.setAttribute("customers", customers);
//3.转发到index.jsp
req.getRequestDispatcher("/index.jsp").forward(req, resp);
}
private void delete(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
System.out.println("delete");
}
}
