简单MVC实现增删改查

反射工具类RelfectionUtils

 package Utils;

 import java.lang.reflect.Field;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.lang.reflect.Modifier;
 import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;

 /**
  * 反射的 Utils 函数集合
  * 提供访问私有变量, 获取泛型类型 Class, 提取集合中元素属性等 Utils 函数
  * @author Administrator
  *
  */
 public class ReflectionUtils {

     /**
      * 通过反射, 获得定义 Class 时声明的父类的泛型参数的类型
      * 如: public EmployeeDao extends BaseDao<Employee, String>
      * @param clazz
      * @param index
      * @return
      */
     @SuppressWarnings("unchecked")
     public static Class getSuperClassGenricType(Class clazz, int index){
         Type genType = clazz.getGenericSuperclass();

         if(!(genType instanceof ParameterizedType)){
             return Object.class;
         }

         Type [] params = ((ParameterizedType)genType).getActualTypeArguments();

         if(index >= params.length || index < 0){
             return Object.class;
         }

         if(!(params[index] instanceof Class)){
             return Object.class;
         }

         return (Class) params[index];
     }

     /**
      * 通过反射, 获得 Class 定义中声明的父类的泛型参数类型
      * 如: public EmployeeDao extends BaseDao<Employee, String>
      * @param <T>
      * @param clazz
      * @return
      */
     @SuppressWarnings("unchecked")
     public static<T> Class<T> getSuperGenericType(Class clazz){
         return getSuperClassGenricType(clazz, 0);
     }

     /**
      * 循环向上转型, 获取对象的 DeclaredMethod
      * @param object
      * @param methodName
      * @param parameterTypes
      * @return
      */
     public static Method getDeclaredMethod(Object object, String methodName, Class<?>[] parameterTypes){

         for(Class<?> superClass = object.getClass(); superClass != Object.class; superClass = superClass.getSuperclass()){
             try {
                 //superClass.getMethod(methodName, parameterTypes);
                 return superClass.getDeclaredMethod(methodName, parameterTypes);
             } catch (NoSuchMethodException e) {
                 //Method 不在当前类定义, 继续向上转型
             }
             //..
         }

         return null;
     }

     /**
      * 使 filed 变为可访问
      * @param field
      */
     public static void makeAccessible(Field field){
         if(!Modifier.isPublic(field.getModifiers())){
             field.setAccessible(true);
         }
     }

     /**
      * 循环向上转型, 获取对象的 DeclaredField
      * @param object
      * @param filedName
      * @return
      */
     public static Field getDeclaredField(Object object, String filedName){

         for(Class<?> superClass = object.getClass(); superClass != Object.class; superClass = superClass.getSuperclass()){
             try {
                 return superClass.getDeclaredField(filedName);
             } catch (NoSuchFieldException e) {
                 //Field 不在当前类定义, 继续向上转型
             }
         }
         return null;
     }

     /**
      * 直接调用对象方法, 而忽略修饰符(private, protected)
      * @param object
      * @param methodName
      * @param parameterTypes
      * @param parameters
      * @return
      * @throws InvocationTargetException
      * @throws IllegalArgumentException
      */
     public static Object invokeMethod(Object object, String methodName, Class<?> [] parameterTypes,
             Object [] parameters) throws InvocationTargetException{

         Method method = getDeclaredMethod(object, methodName, parameterTypes);

         if(method == null){
             throw new IllegalArgumentException("Could not find method [" + methodName + "] on target [" + object + "]");
         }

         method.setAccessible(true);

         try {
             return method.invoke(object, parameters);
         } catch(IllegalAccessException e) {
             System.out.println("不可能抛出的异常");
         } 

         return null;
     }

     /**
      * 直接设置对象属性值, 忽略 private/protected 修饰符, 也不经过 setter
      * @param object
      * @param fieldName
      * @param value
      */
     public static void setFieldValue(Object object, String fieldName, Object value){
         Field field = getDeclaredField(object, fieldName);

         if (field == null)
             throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + object + "]");

         makeAccessible(field);

         try {
             field.set(object, value);
         } catch (IllegalAccessException e) {
             System.out.println("不可能抛出的异常");
         }
     }

     /**
      * 直接读取对象的属性值, 忽略 private/protected 修饰符, 也不经过 getter
      * @param object
      * @param fieldName
      * @return
      */
     public static Object getFieldValue(Object object, String fieldName){
         Field field = getDeclaredField(object, fieldName);

         if (field == null)
             throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + object + "]");

         makeAccessible(field);

         Object result = null;

         try {
             result = field.get(object);
         } catch (IllegalAccessException e) {
             System.out.println("不可能抛出的异常");
         }

         return result;
     }
 }

jdbcutils

 package Utils;

 import java.sql.Connection;
 import java.sql.SQLException;

 import javax.sql.DataSource;

 import com.mchange.v2.c3p0.ComboPooledDataSource;

 public class JdbcUtil {

     public static void reaseConnection(Connection connection) {
         try {
             if(connection!=null){
                 connection.close();
             }
         } catch (SQLException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }
     }
     private static DataSource dataSource = null;
     static{
         dataSource = new ComboPooledDataSource("mvc");
     }

     public static DataSource getDataSource(){
         return dataSource;
     }

     public static Connection getConnection(){
         try {
             return dataSource.getConnection();
         } catch (SQLException e) {
             // TODO Auto-generated catch block
             //e.printStackTrace();
             System.out.println("连接失败");
         }
         return null;

     }
 }

DAO操作类 依靠c3p0，dbutil

 package com.mvc.dao;

 import java.lang.reflect.ParameterizedType;
 import java.lang.reflect.Type;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.List;

 import org.apache.commons.dbutils.QueryRunner;
 import org.apache.commons.dbutils.handlers.BeanHandler;
 import org.apache.commons.dbutils.handlers.BeanListHandler;
 import org.apache.commons.dbutils.handlers.ScalarHandler;
 import org.apache.el.util.ReflectionUtil;

 import com.sun.org.apache.bcel.internal.generic.NEW;

 import Utils.JdbcUtil;
 import Utils.ReflectionUtils;

 public class Dao<T> {
     private Class<T> clazz;
     private QueryRunner queryRunner= new QueryRunner(JdbcUtil.getDataSource());
     public Dao() {
         clazz = ReflectionUtils.getSuperGenericType(this.getClass());
     }
     public <E> E getForValue(String sql,Object ...arg){
         try {
             return (E) queryRunner.query(sql,new ScalarHandler(),arg);
         } catch (SQLException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
             System.out.println("getForValue error");
         }
         return null;

     }
     public List<T> getForList(String sql,Object ...args){
         try {
             return queryRunner.query(sql, new BeanListHandler<>(clazz),args);
         } catch (SQLException e) {
             System.out.println("getForList error");
         }
         return null;

     }
     public T get(String sql,Object ...args){
         try {
             return queryRunner.query(sql,new BeanHandler<>(clazz),args);
         } catch (SQLException e) {
             // TODO Auto-generated catch block
             //e.printStackTrace();
             System.out.println("get error");
         }
         return null;
     }

     public void updata(String sql,Object ...args){
         try {
             queryRunner.update(sql,args);
         } catch (SQLException e) {
             // TODO Auto-generated catch block
             //e.printStackTrace();
             System.out.println("updata error");
         }
     }
 }

Customer类

package com.mvc.domain;

public class Customer {
    private String id;
    private String name;
    private String address;
    private String phone;
    private int count;

    public Customer() {
        super();
    }
    public Customer(String id, String name, String address, String phone) {
        super();
        this.id = id;
        this.name = name;
        this.address = address;
        this.phone = phone;
        this.count = 0;
    }

    public int getCount() {
        return count;
    }
    public void setCount(int count) {
        this.count = count;
    }
    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getAddress() {
        return address;
    }
    public void setAddress(String address) {
        this.address = address;
    }
    public String getPhone() {
        return phone;
    }
    public void setPhone(String phone) {
        this.phone = phone;
    }
    @Override
    public String toString() {
        return "Customer [id=" + id + ", name=" + name + ", address=" + address + ", phone=" + phone + "]";
    }

}

CustomerDao接口

 package com.mvc.dao;

 import java.util.List;

 import com.mvc.domain.CriteriaCustomer;
 import com.mvc.domain.Customer;

 public interface CustomerDao {
     public List<Customer> getAll();
     public void save(Customer customer);
     public void upCount(Customer customer);
     public void upAll(Customer customer);
     public Customer getForIdName(String id,String name);
     public Customer getForId(String id);
     public void delete(String id);
     public long getCountWithName(String name);
     public long getCountWithId(String id);
     public List<Customer> getCriteriaCustomers(CriteriaCustomer cc);
 }

操作类

 package com.mvc.jdbc;

 import java.sql.SQLException;
 import java.util.List;

 import com.mvc.dao.CustomerDao;
 import com.mvc.dao.Dao;
 import com.mvc.domain.CriteriaCustomer;
 import com.mvc.domain.Customer;

 public class CustomerDaoJdbc extends Dao<Customer> implements CustomerDao{

     @Override
     public List<Customer> getAll(){
         // TODO Auto-generated method stub
         String sql = "SELECT * FROM customer";
         return getForList(sql);
     }

     @Override
     public void save(Customer customer) {
         // TODO Auto-generated method stub
         String sql = "insert into customer(id,name,address,phone,count) value(?,?,?,?,?)";
         updata(sql,customer.getId(),customer.getName(),customer.getAddress(),customer.getPhone(),customer.getCount());

     }

     @Override
     public void upAll(Customer customer) {
         // TODO Auto-generated method stub
         String sql = "UPDATE customer SET NAME=?,ADDRESS=?,PHONE=?  WHERE ID=?";
         updata(sql,customer.getName(),customer.getAddress(),customer.getPhone(),customer.getId());

     }

     @Override
     public void upCount(Customer customer) {
         // TODO Auto-generated method stub
         String sql = "UPDATE customer SET COUNT=? WHERE ID=?";
         updata(sql,customer.getCount(),customer.getId());
     }

     @Override
     public Customer getForIdName(String id,String name) {
         // TODO Auto-generated method stub
         String sql = "SELECT id,name,address,phone,count FROM customer where id = ? and name = ?";
         return get(sql,id,name);
     }
     @Override
     public Customer getForId(String id) {
         // TODO Auto-generated method stub
         String sql = "SELECT id,name,address,phone,count FROM customer where id = ?";
         return get(sql,id);
     }
     @Override
     public void delete(String id) {
         // TODO Auto-generated method stub
         String sql = "delete from customer where ID = ? ";
         updata(sql,id);

     }

     @Override
     public long getCountWithName(String name) {
         // TODO Auto-generated method stub
         String sql = "select count(id) from customer where name = ?";
         return (long)getForValue(sql, name);
     }

     @Override
     public List<Customer> getCriteriaCustomers(CriteriaCustomer cc) {
         // TODO Auto-generated method stub
         String sql = "SELECT * FROM customer WHERE NAME LIKE ? AND address LIKE ? AND phone LIKE ?";
         System.out.println(cc.getName()+cc.getAddress()+cc.getPhone());
         return getForList(sql,cc.getName(),cc.getAddress(),cc.getPhone());
     }

     @Override
     public long getCountWithId(String id) {
         // TODO Auto-generated method stub
                 String sql = "select count(id) from customer where id= ?";
                 return (long)getForValue(sql, id);
     }

 }

servlet

 package com.mvc.servlet;

 import java.io.IOException;
 import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.List;

 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.mvc.dao.CustomerDao;
 import com.mvc.domain.CriteriaCustomer;
 import com.mvc.domain.Customer;
 import com.mvc.jdbc.CustomerDaoJdbc;
 import com.sun.corba.se.impl.protocol.giopmsgheaders.Message;

 import jdk.nashorn.internal.ir.RuntimeNode.Request;

 /**
  * Servlet implementation class SqlServlet
  */
 @WebServlet("/SqlServlet")
 public class SqlServlet extends HttpServlet {
     private static final long serialVersionUID = 1L;

     /**
      * @see HttpServlet#HttpServlet()
      */
     CustomerDao customerDao = null;

     public SqlServlet() {
         super();
         // TODO Auto-generated constructor stub
         customerDao = new CustomerDaoJdbc();
     }

     /**
      * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
      *      response)
      */
     protected void doGet(HttpServletRequest request,
             HttpServletResponse response) throws ServletException, IOException {
         // TODO Auto-generated method stub
         doPost(request, response);
     }

     /**
      * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
      *      response)
      */
     protected void doPost(HttpServletRequest request,
             HttpServletResponse response) throws ServletException, IOException {
         // TODO Auto-generated method stub
         request.setCharacterEncoding("utf-8");
         String servletPath = request.getServletPath();
         // System.out.println(servletPath);
         servletPath = servletPath.substring(1, servletPath.length() - 3);
         try {
             Method method = getClass().getDeclaredMethod(servletPath,
                     HttpServletRequest.class, HttpServletResponse.class);
             method.invoke(this, request, response);
         } catch (Exception e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }

     }

     @SuppressWarnings("unused")
     private void edit(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException {
         System.out.println("edit");
         String id = request.getParameter("id");
         System.out.println(id);
         Customer customer = customerDao.getForId(id);
         System.out.println(customer);
         request.setAttribute("customer", customer);
         request.getRequestDispatcher("/updata.jsp").forward(request, response);
     }

     @SuppressWarnings("unused")
     private void updata(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException {
         System.out.println("updata");
         String id = request.getParameter("id");
         String name = request.getParameter("name");
         String address = request.getParameter("address");
         String phone = request.getParameter("phone");
         Customer customer = new Customer(id, name, address, phone);
         String massage;
         massage = "修改成功";
         customerDao.upAll(customer);
         request.setAttribute("massage", massage);
         request.setAttribute("customer", customer);
         request.getRequestDispatcher("/updata.jsp").forward(request, response);

     }

     @SuppressWarnings("unused")
     private void add(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException {
         System.out.println("add");
         String id = request.getParameter("id");
         String name = request.getParameter("name");
         String address = request.getParameter("address");
         String phone = request.getParameter("phone");
         Customer customer = new Customer(id, name, address, phone);
         System.out.println(customer);
         long count = customerDao.getCountWithName(name);
         long count1 = customerDao.getCountWithId(id);
         System.out.println("count:" + count);
         request.setAttribute("id", id);
         request.setAttribute("name", name);
         request.setAttribute("address", address);
         request.setAttribute("phone", phone);
         if (count1 > 0) {
             request.setAttribute("massage", "学号已存在，报名失败");
             request.getRequestDispatcher("/newcustomer.jsp").forward(request,
                     response);
         } else {
             request.setAttribute("massage", "报名成功");
             customerDao.save(customer);
             request.getRequestDispatcher("/newcustomer.jsp").forward(request,
                     response);
         }
     }

     @SuppressWarnings("unused")
     private void delete(HttpServletRequest request, HttpServletResponse response)
             throws IOException {
         System.out.println("delete");
         String id = request.getParameter("id");
         System.out.println(id);
         //customerDao.delete(id);

         //response.sendRedirect("query.do");
     }

     @SuppressWarnings("unused")
     private void query(HttpServletRequest request, HttpServletResponse response) {
         String name = request.getParameter("name");
         String address = request.getParameter("address");
         String phone = request.getParameter("phone");
         System.out.println(name + address + phone);
         System.out.println("query");
         CriteriaCustomer cc = new CriteriaCustomer(name, address, phone);
         List<Customer> customers = customerDao.getCriteriaCustomers(cc);
         request.setAttribute("customers", customers);
         try {
             request.getRequestDispatcher("/1.jsp").forward(request,
                     response);
         } catch (ServletException | IOException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }
     }

     @SuppressWarnings("unused")
     private void come(HttpServletRequest request, HttpServletResponse response) {
         String name = request.getParameter("name");
         String id = request.getParameter("id");
         Customer customer = customerDao.getForIdName(id, name);
         System.out.println(customer);
         if (customer != null) {
             request.setAttribute("massage", "");
             customer.setCount(customer.getCount() + 1);
             customerDao.upCount(customer);
                 //response.sendRedirect("NewFile_1.jsp");
                 try {
                     request.getRequestDispatcher("/NewFile_1.jsp").forward(request,
                             response);
                 } catch (ServletException | IOException e) {
                     // TODO Auto-generated catch block
                     e.printStackTrace();
                 }

         } else {
             try {
                 String massage = "名字或学号错误";
                 request.setAttribute("massage", massage);
                 request.setAttribute("id", id);
                 request.setAttribute("name", name);
                 request.getRequestDispatcher("/come.jsp").forward(request,
                         response);
             } catch (ServletException | IOException e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }
         }
     }
 }

以下jsp代码 css样式等为网上找的素材

1.增加用户的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">
 <!--[if IE]><meta http-equiv="x-ua-compatible" content="IE=9" /><![endif]-->
 <meta name="viewport" content="width=device-width, initial-scale=1">
  <meta name="description" content="Your Description Here">
  <meta name="keywords"
     content="bootstrap themes, portfolio, responsive theme">
 <meta name="author" content="ThemeForces.Com">

 <!-- Favicons
     ================================================== -->
   <!-- <link rel="shortcut-icon" href="img/favicon.ico" type="image/x-icon"> -->
  <!-- <link rel="apple-touch-icon" href="img/apple-touch-icon.png">  -->
    <link rel="apple-touch-icon" sizes="72x72"
     href="img/apple-touch-icon-72x72.png">
  <link rel="apple-touch-icon" sizes="114x114"
     href="img/apple-touch-icon-114x114.png">

 <!-- Bootstrap -->
   <link rel="stylesheet" type="text/css" href="css/bootstrap.css">
 <!-- <link rel="stylesheet" type="text/css"
     href="fonts/font-awesome/css/font-awesome.css"> -->

 <!-- Stylesheet
     ================================================== -->
   <link rel="stylesheet" type="text/css" href="css/style.css">
    <!--  <link rel="stylesheet" type="text/css" href="css/responsive.css"> --> 

 <!-- <script type="text/javascript" src="js/modernizr.custom.js"></script> -->

 <title></title>
 </head>
 <body>
     <h3 style="text-align: center;"><font color="red"><c:out value="${massage}"></c:out></font></h3>
     <div id="tf-contact">
         <div class="container">
             <div class="section-title">
                 <hr>
             </div>

             <div class="space"></div>

             <div class="row">
                 <div class="col-md-6 col-md-offset-3">
                     <form id="contact" action="add.do" method="post">
                         <div class="form-group">
                             <input class="form-control" id="exampleInputEmail1" type="text"
                                 name="id" value="${id}" placeholder="长学号" />
                         </div>

                         <div class="form-group">
                             <input class="form-control" type="text" name="name"
                                 value="${name}" placeholder="姓名" />
                         </div>

                         <div class="form-group">
                             <input class="form-control" type="text" name="address"
                                 value="${address}" placeholder="班级" />
                         </div>

                         <td><div class="form-group">
                                 <input class="form-control" type="text" name="phone"
                                     value="${phone}" placeholder="手机" />
                             </div>
                             <input class="btn btn-primary my-btn dark" type="submit"
                             value="--报名--" />
                     </form>
                 </div>
             </div>
         </div>
     </div>
     <!--  <script type="text/javascript" src="js/jquery.1.11.1.js"></script>-->
     <!-- Include all compiled plugins (below), or include individual files as needed -->
     <!--  <script type="text/javascript" src="js/bootstrap.js"></script> -->

     <!-- Javascripts
     ================================================== -->
      <!--  <script type="text/javascript" src="js/main.js"></script>-->
 </body>
 </html>

2.查询

 <%@ 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>
 <script type="text/javascript" src="scripts/jquery-1.7.2.js"></script>
 <script type="text/javascript">
 </script>
 </head>
 <body>

     <form action="query.do" method="post">
         <table>
             <tr>
                 <td>CustomerName:</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="newcustomer.jsp">Add New Customer</a></td>
             </tr>
         </table>
     </form>

     <br><br>

     <c:if test="${!empty requestScope.customers }">

         <hr>
         <br><br>

         <table border="1" cellpadding="10" cellspacing="0">
             <tr>
                 <th>^ID</th>
                 <th>CustomerName</th>
                 <th>Address</th>
                 <th>Phone</th>
                 <th>UPDATE\DELETE</th>
             </tr>

             <c:forEach items="${requestScope.customers }" var="cust">

                     <tr>
                         <td>${cust.id }</td>
                         <td>${cust.name }</td>
                         <td>${cust.address }</td>
                         <td>${cust.phone }</td>
                         <td>
                             <c:url value="/edit.do" var="editurl">
                                 <c:param name="id" value="${cust.id }"></c:param>
                             </c:url>
                             <a href="${editurl }">UPDATE</a>
                             <c:url value="/delete.do" var="deleteurl">
                                 <c:param name="id" value="${cust.id }"></c:param>
                             </c:url>
                             <a href="${deleteurl }" class="delete">DELETE</a>
                         </td>
                     </tr>

             </c:forEach>

         </table>
     </c:if>

 </body>
 </html>

3.删除

<%@ 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>
<script type="text/javascript" src="scripts/jquery-1.7.2.js"></script>

</head>
<body>

    <form action="query.do" method="post">
        <table>
            <tr>
                <td>CustomerName:</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="newcustomer.jsp">Add New Customer</a></td>
            </tr>
        </table>
    </form>

    <br><br>

    <c:if test="${!empty requestScope.customers }">

        <hr>
        <br><br>

        <table border="1" cellpadding="10" cellspacing="0">
            <tr>
                <th>^ID</th>
                <th>CustomerName</th>
                <th>Address</th>
                <th>Phone</th>
                <th>UPDATE\DELETE</th>
            </tr>

            <c:forEach items="${requestScope.customers }" var="cust">

                    <tr>
                        <td>${cust.id }</td>
                        <td>${cust.name }</td>
                        <td>${cust.address }</td>
                        <td>${cust.phone }</td>
                        <td>
                            <c:url value="/edit.do" var="editurl">
                                <c:param name="id" value="${cust.id }"></c:param>
                            </c:url>
                            <a href="${editurl }">UPDATE</a>
                            <c:url value="/delete.do" var="deleteurl">
                                <c:param name="id" value="${cust.id }"></c:param>
                            </c:url>
                            <a href="${deleteurl }" class="delete">DELETE</a>
                        </td>
                    </tr>

            </c:forEach>

        </table>
    </c:if>

</body>
</html>

4.修改

<%@ 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">
<!--[if IE]><meta http-equiv="x-ua-compatible" content="IE=9" /><![endif]-->
<meta name="viewport" content="width=device-width, initial-scale=1">
<meta name="description" content="Your Description Here">
<meta name="keywords"
    content="bootstrap themes, portfolio, responsive theme">
<meta name="author" content="ThemeForces.Com">

<!-- Favicons
    ================================================== -->
<link rel="shortcut icon" href="img/favicon.ico" type="image/x-icon">
<link rel="apple-touch-icon" href="img/apple-touch-icon.png">
<link rel="apple-touch-icon" sizes="72x72"
    href="img/apple-touch-icon-72x72.png">
<link rel="apple-touch-icon" sizes="114x114"
    href="img/apple-touch-icon-114x114.png">

<!-- Bootstrap -->
<link rel="stylesheet" type="text/css" href="css/bootstrap.css">
<link rel="stylesheet" type="text/css"
    href="fonts/font-awesome/css/font-awesome.css">

<!-- Stylesheet
    ================================================== -->
<link rel="stylesheet" type="text/css" href="css/style.css">
<link rel="stylesheet" type="text/css" href="css/responsive.css">

<script type="text/javascript" src="js/modernizr.custom.js"></script>

<title></title>
</head>
<body>

    <c:if test="${requestScope.massage != null }">
        <br>
        <h3 style="text-align: center;"><font color="red"><c:out value="${massage}"></c:out></font></h3>
        <br>
        <br>
    </c:if>

    <c:set var="id" value="${customer != null ? customer.id : param.id }"></c:set>

    <c:set var="name"
        value="${customer != null ? customer.name : param.name }"></c:set>
    <c:set var="address"
        value="${customer != null ? customer.address : param.address }"></c:set>
    <c:set var="phone"
        value="${customer != null ? customer.phone : param.phone }"></c:set>
    <div id="tf-contact">
        <div class="container">
            <div class="section-title">

                <hr>
            </div>

            <div class="space"></div>

            <div class="row">
                <div class="col-md-6 col-md-offset-3">
                    <form id="contact" action="updata.do" method="post">
                    <input type="hidden" name="id" value="${id }"></input>
                        <div class="form-group">
                            <h4>姓名:</h4>
                            <input class="form-control" type="text" name="name"
                                value="${name}" placeholder="姓名" />
                        </div>

                        <div class="form-group">
                            <h4>班级:</h4>
                            <input class="form-control" type="text" name="address"
                                value="${address}" placeholder="班级" />
                        </div>

                        <div class="form-group">
                                <h4>手机:</h4>
                                <input class="form-control" type="text" name="phone"
                                    value="${phone}" placeholder="手机" />
                            </div> <input class="btn btn-primary my-btn dark" type="submit"
                            value="修改" />
                    </form>
                </div>
            </div>
        </div>
    </div>
    <script type="text/javascript" src="js/jquery.1.11.1.js"></script>
    <!-- Include all compiled plugins (below), or include individual files as needed -->
    <script type="text/javascript" src="js/bootstrap.js"></script>

    <!-- Javascripts
    ================================================== -->
    <script type="text/javascript" src="js/main.js"></script>
</body>
</html>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://java.sun.com/xml/ns/javaee"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
    id="WebApp_ID" version="3.0">
    <display-name>MVC</display-name>

    <servlet>
        <description></description>
        <display-name>SqlServlet</display-name>
        <servlet-name>SqlServlet</servlet-name>
        <servlet-class>com.mvc.servlet.SqlServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>SqlServlet</servlet-name>
        <url-pattern>*.do</url-pattern>
    </servlet-mapping>

</web-app>

运行效果 增加信息

数据库内数据