这篇文档介绍了如何使用Spring MVC和JdbcTemplate开发一个简单的CRUD（创建、读取、更新和删除）应用程序。下面是每个部分的概述和内容翻译：

创建数据表

这里使用了MySQL数据库中的emp99表。它有4个字段：id、name、salary和designation。其中，id是自增的，由序列生成。

spring-mvc-crud-example-table.png

Spring MVC CRUD示例

1. 在pom.xml文件中添加依赖项。

这里展示了pom.xml文件中的依赖项，涵盖了Spring Web MVC、Apache Tomcat Jasper、Servlet API、JSTL和MySQL Connector等。

<!-- https://mvnrepository.com/artifact/org.springframework/spring-webmvc -->  
<dependency>  
    <groupId>org.springframework</groupId>  
    <artifactId>spring-webmvc</artifactId>  
    <version>5.1.1.RELEASE</version>  
</dependency>  
  
<!-- https://mvnrepository.com/artifact/org.apache.tomcat/tomcat-jasper -->  
<dependency>  
    <groupId>org.apache.tomcat</groupId>  
    <artifactId>tomcat-jasper</artifactId>  
    <version>9.0.12</version>  
</dependency>  
    <!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->  
<dependency>    
    <groupId>javax.servlet</groupId>    
    <artifactId>servlet-api</artifactId>    
    <version>3.0-alpha-1</version>    
</dependency>  
<!-- https://mvnrepository.com/artifact/javax.servlet/jstl -->  
<dependency>  
    <groupId>javax.servlet</groupId>  
    <artifactId>jstl</artifactId>  
    <version>1.2</version>  
</dependency>  
    <!-- https://mvnrepository.com/artifact/mysql/mysql-connector-java -->  
<dependency>  
    <groupId>mysql</groupId>  
    <artifactId>mysql-connector-java</artifactId>  
    <version>8.0.11</version>  
</dependency>  
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-jdbc -->  
<dependency>  
    <groupId>org.springframework</groupId>  
    <artifactId>spring-jdbc</artifactId>  
    <version>5.1.1.RELEASE</version>  
</dependency>

2. 创建Bean类

这是一个包含与数据库字段相对应的变量（以及setter和getter方法）的Bean类。它表示数据库中的实体。

package cn.javatiku.beans;    
    
public class Emp {    
private int id;    
private String name;    
private float salary;    
private String designation;    
    
public int getId() {    
    return id;    
}    
public void setId(int id) {    
    this.id = id;    
}    
public String getName() {    
    return name;    
}    
public void setName(String name) {    
    this.name = name;    
}    
public float getSalary() {    
    return salary;    
}    
public void setSalary(float salary) {    
    this.salary = salary;    
}    
public String getDesignation() {    
    return designation;    
}    
public void setDesignation(String designation) {    
    this.designation = designation;    
}    
    
}

3. 创建Controller类

这个Controller类处理与前端交互的逻辑。它包含了添加、保存、编辑、更新和删除等操作的方法。

package cn.javatiku.controllers;     
import java.util.List;    
import org.springframework.beans.factory.annotation.Autowired;    
import org.springframework.stereotype.Controller;  
import org.springframework.ui.Model;  
import org.springframework.web.bind.annotation.ModelAttribute;    
import org.springframework.web.bind.annotation.PathVariable;    
import org.springframework.web.bind.annotation.RequestMapping;    
import org.springframework.web.bind.annotation.RequestMethod;     
import cn.javatiku.beans.Emp;    
import cn.javatiku.dao.EmpDao;    
@Controller    
public class EmpController {    
    @Autowired    
    EmpDao dao;//will inject dao from XML file    
        
    /*It displays a form to input data, here "command" is a reserved request attribute  
     *which is used to display object data into form  
     */    
    @RequestMapping("/empform")    
    public String showform(Model m){    
        m.addAttribute("command", new Emp());  
        return "empform";   
    }    
    /*It saves object into database. The @ModelAttribute puts request data  
     *  into model object. You need to mention RequestMethod.POST method   
     *  because default request is GET*/    
    @RequestMapping(value="/save",method = RequestMethod.POST)    
    public String save(@ModelAttribute("emp") Emp emp){    
        dao.save(emp);    
        return "redirect:/viewemp";//will redirect to viewemp request mapping    
    }    
    /* It provides list of employees in model object */    
    @RequestMapping("/viewemp")    
    public String viewemp(Model m){    
        List<Emp> list=dao.getEmployees();    
        m.addAttribute("list",list);  
        return "viewemp";    
    }    
    /* It displays object data into form for the given id.   
     * The @PathVariable puts URL data into variable.*/    
    @RequestMapping(value="/editemp/{id}")    
    public String edit(@PathVariable int id, Model m){    
        Emp emp=dao.getEmpById(id);    
        m.addAttribute("command",emp);  
        return "empeditform";    
    }    
    /* It updates model object. */    
    @RequestMapping(value="/editsave",method = RequestMethod.POST)    
    public String editsave(@ModelAttribute("emp") Emp emp){    
        dao.update(emp);    
        return "redirect:/viewemp";    
    }    
    /* It deletes record for the given id in URL and redirects to /viewemp */    
    @RequestMapping(value="/deleteemp/{id}",method = RequestMethod.GET)    
    public String delete(@PathVariable int id){    
        dao.delete(id);    
        return "redirect:/viewemp";    
    }     
}

4. 创建DAO类

DAO（数据访问对象）类用于访问数据库并执行数据操作。它包含了保存、更新、删除和查询数据的方法。

package cn.javatiku.dao;    
import java.sql.ResultSet;    
import java.sql.SQLException;    
import java.util.List;    
import org.springframework.jdbc.core.BeanPropertyRowMapper;    
import org.springframework.jdbc.core.JdbcTemplate;    
import org.springframework.jdbc.core.RowMapper;    
import cn.javatiku.beans.Emp;    
    
public class EmpDao {    
JdbcTemplate template;    
    
public void setTemplate(JdbcTemplate template) {    
    this.template = template;    
}    
public int save(Emp p){    
    String sql="insert into Emp99(name,salary,designation) values('"+p.getName()+"',"+p.getSalary()+",'"+p.getDesignation()+"')";    
    return template.update(sql);    
}    
public int update(Emp p){    
    String sql="update Emp99 set name='"+p.getName()+"', salary="+p.getSalary()+",designation='"+p.getDesignation()+"' where id="+p.getId()+"";    
    return template.update(sql);    
}    
public int delete(int id){    
    String sql="delete from Emp99 where id="+id+"";    
    return template.update(sql);    
}    
public Emp getEmpById(int id){    
    String sql="select * from Emp99 where id=?";    
    return template.queryForObject(sql, new Object[]{id},new BeanPropertyRowMapper<Emp>(Emp.class));    
}    
public List<Emp> getEmployees(){    
    return template.query("select * from Emp99",new RowMapper<Emp>(){    
        public Emp mapRow(ResultSet rs, int row) throws SQLException {    
            Emp e=new Emp();    
            e.setId(rs.getInt(1));    
            e.setName(rs.getString(2));    
            e.setSalary(rs.getFloat(3));    
            e.setDesignation(rs.getString(4));    
            return e;    
        }    
    });    
}    
}

5. 在web.xml文件中配置Controller的入口

在web.xml文件中，配置了DispatcherServlet，以便将请求路由到相应的Controller。

<?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>SpringMVC</display-name>  
   <servlet>    
    <servlet-name>spring</servlet-name>    
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>    
    <load-on-startup>1</load-on-startup>      
</servlet>    
<servlet-mapping>    
    <servlet-name>spring</servlet-name>    
    <url-pattern>/</url-pattern>    
</servlet-mapping>    
</web-app>

6. 在XML文件中定义Bean

在spring-servlet.xml文件中，配置了Spring的bean，包括视图解析器、数据源和JdbcTemplate等。

<?xml version="1.0" encoding="UTF-8"?>  
<beans xmlns="http://www.springframework.org/schema/beans"  
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"   
    xmlns:context="http://www.springframework.org/schema/context"  
    xmlns:mvc="http://www.springframework.org/schema/mvc"  
    xsi:schemaLocation="  
        http://www.springframework.org/schema/beans  
        http://www.springframework.org/schema/beans/spring-beans.xsd  
        http://www.springframework.org/schema/context  
        http://www.springframework.org/schema/context/spring-context.xsd  
        http://www.springframework.org/schema/mvc  
        http://www.springframework.org/schema/mvc/spring-mvc.xsd">  
<context:component-scan base-package="cn.javatiku.controllers"></context:component-scan>    
    
<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">    
<property name="prefix" value="/WEB-INF/jsp/"></property>    
<property name="suffix" value=".jsp"></property>    
</bean>    
    
<bean id="ds" class="org.springframework.jdbc.datasource.DriverManagerDataSource">    
<property name="driverClassName" value="com.mysql.jdbc.Driver"></property>    
<property name="url" value="jdbc:mysql://localhost:3306/test"></property>    
<property name="username" value=""></property>    
<property name="password" value=""></property>    
</bean>    
    
<bean id="jt" class="org.springframework.jdbc.core.JdbcTemplate">    
<property name="dataSource" ref="ds"></property>    
</bean>    
    
<bean id="dao" class="cn.javatiku.dao.EmpDao">    
<property name="template" ref="jt"></property>    
</bean>       
</beans>

7. 创建请求页面

这里展示了一个简单的index.jsp页面

<a href="empform">Add Employee</a>  
<a href="viewemp">View Employees</a>

8. 创建其他视图组件

这里展示了empform.jsp、empeditform.jsp和viewemp.jsp页面的内容，分别用于添加、编辑和查看员工的操作。

empform.jsp

<%@ taglib uri="http://www.springframework.org/tags/form" prefix="form"%>    
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>    
  
        <h1>Add New Employee</h1>  
       <form:form method="post" action="save">    
        <table >    
         <tr>    
          <td>Name : </td>   
          <td><form:input path="name"  /></td>  
         </tr>    
         <tr>    
          <td>Salary :</td>    
          <td><form:input path="salary" /></td>  
         </tr>   
         <tr>    
          <td>Designation :</td>    
          <td><form:input path="designation" /></td>  
         </tr>   
         <tr>    
          <td> </td>    
          <td><input type="submit" value="Save" /></td>    
         </tr>    
        </table>    
       </form:form>

empeditform.jsp

<%@ taglib uri="http://www.springframework.org/tags/form" prefix="form"%>    
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>    
  
        <h1>Edit Employee</h1>  
       <form:form method="POST" action="/SpringMVCCRUDSimple/editsave">    
        <table >    
        <tr>  
        <td></td>    
         <td><form:hidden  path="id" /></td>  
         </tr>   
         <tr>    
          <td>Name : </td>   
          <td><form:input path="name"  /></td>  
         </tr>    
         <tr>    
          <td>Salary :</td>    
          <td><form:input path="salary" /></td>  
         </tr>   
         <tr>    
          <td>Designation :</td>    
          <td><form:input path="designation" /></td>  
         </tr>   
           
         <tr>    
          <td> </td>    
          <td><input type="submit" value="Edit Save" /></td>    
         </tr>    
        </table>    
       </form:form>

viewemp.jsp

   <%@ taglib uri="http://www.springframework.org/tags/form" prefix="form"%>    
   <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>    
  
<h1>Employees List</h1>  
<table border="2" width="70%" cellpadding="2">  
<tr><th>Id</th><th>Name</th><th>Salary</th><th>Designation</th><th>Edit</th><th>Delete</th></tr>  
   <c:forEach var="emp" items="${list}">   
   <tr>  
   <td>${emp.id}</td>  
   <td>${emp.name}</td>  
   <td>${emp.salary}</td>  
   <td>${emp.designation}</td>  
   <td><a href="editemp/${emp.id}">Edit</a></td>  
   <td><a href="deleteemp/${emp.id}">Delete</a></td>  
   </tr>  
   </c:forEach>  
   </table>  
   <br/>  
   <a href="empform">Add New Employee</a>

这个示例通过Spring MVC和JdbcTemplate演示了如何开发一个基本的CRUD应用程序。

点击“添加员工”后，您将看到以下表单。

spring-mvc-crud-example-output1.png

填写表单并点击“保存”将条目添加到数据库中。

spring-mvc-crud-example-output2.png

现在，点击“编辑”以对提供的数据进行一些更改。

spring-mvc-crud-example-output3.png

现在，点击“编辑保存”以将带有更改的条目添加到数据库中。

spring-mvc-crud-example-output4.png

现在，点击“删除”以从数据库中删除该条目。

spring-mvc-crud-example-output5.png

下载此示例（使用Eclipse开发）

spring-mvc-crud-example-output6.png

你可以按照这个示例来实践和理解Spring MVC的基本概念和用法。

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