SpringMVC 使用 RESTful 架构实现 CRUD 操作

软件152 余建强

源码下载：http://download.csdn.net/detail/qq_35318576/9826210

1 使用框架

　　SpringMVC、Maven、Ajax、JSTL、JSR303数据校验

2 什么是 RESTful 架构

　　（1）简而言之，我们总结一下什么是RESTful架构：

　　　　1）每一个URI代表一种资源；

　　　　2）客户端和服务器之间，传递这种资源的某种表现层；

　　　　3）客户端通过四个HTTP动词，对服务器端资源进行操作，实现"表现层状态转化"。

　　（2）四个表示操作方式的动词：GET、POST、PUT、DELETE。

　　　　它们分别对应四种基本操作：GET用来获取资源，POST用来新建资源（也可以用于更新资源），PUT用来更新资源，DELETE用来删除资源。

3 实现步骤

　　（1）Maven 需要导入的 jar 包，pom.xml 部分配置

<dependencies>
    <!-- Servlet API -->
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>3.1.0</version>
        <scope>provided</scope> <!-- 编译时用到servlet-api和jsp-api，但在打包的时候不用这两个依赖 -->
    </dependency>

    <!-- JSP API -->
    <dependency>
        <groupId>javax.servlet.jsp</groupId>
        <artifactId>jsp-api</artifactId>
        <version>2.2</version>
        <scope>provided</scope> <!-- 编译时用到servlet-api和jsp-api，但在打包的时候不用这两个依赖 -->
    </dependency>
    
    <!-- JUnit -->
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.11</version>
        <scope>test</scope>
    </dependency>
    
    <!-- jstl -->
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>jstl</artifactId>
        <version>1.2</version>
    </dependency>
    
    <!-- standard -->
    <dependency>
        <groupId>taglibs</groupId>
        <artifactId>standard</artifactId>
        <version>1.1.2</version>
    </dependency>
    
    <!-- spring-context -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>4.1.6.RELEASE</version>
    </dependency>
    
    <!-- spring-web -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-web</artifactId>
        <version>4.1.6.RELEASE</version>
    </dependency>
    
    <!-- spring-webmvc -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>4.1.6.RELEASE</version>
    </dependency>
    
    <!-- hibernate-validator-annotation-processor -->
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-validator-annotation-processor</artifactId>
        <version>5.0.3.Final</version>
    </dependency>
    
    <!-- hibernate-validator -->
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-validator</artifactId>
        <version>5.0.3.Final</version>
    </dependency>
  </dependencies>

　　（2）web.xml 文件配置

<?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_170422_I18N_JSTLView</display-name>
  
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  
  <!-- Spring 解决中文乱码问题 -->
  <filter>
      <filter-name>encodingFilter</filter-name>
      <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
      <init-param>
          <param-name>encoding</param-name>
          <param-value>UTF-8</param-value>
      </init-param>
  </filter>
  <filter-mapping>
      <filter-name>encodingFilter</filter-name>
      <url-pattern>/*</url-pattern>
  </filter-mapping>
  
  <!--
           配置 org.springframework.web.filter.HiddenHttpMethodFilter：
           可以把 POST 请求转换为 DELETE 或 POST 请求   
  -->
   <filter>
          <filter-name>HiddenHttpMethodFilter</filter-name>
          <filter-class>org.springframework.web.filter.HiddenHttpMethodFilter</filter-class>
   </filter>
   <filter-mapping>
          <filter-name>HiddenHttpMethodFilter</filter-name>
          <url-pattern>/*</url-pattern>
   </filter-mapping>
  
  <!-- The front controller of this Spring Web application, responsible for handling all application requests -->
    <servlet>
        <servlet-name>springDispatcherServlet</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!-- 配置 DispatcherServlet 的一个初始化参数：配置 SpringMVC 配置文件的位置和名称 -->
        <!-- 默认的配置文件格式：/WEB-INF/<servlet-name>-servlet.xml -->
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:spring-mvc.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <!-- Map all requests to the DispatcherServlet for handling -->
    <servlet-mapping>
        <servlet-name>springDispatcherServlet</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
  
</web-app>

　　（3）spring-mvc.xml 文件内容如下

<?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:aop="http://www.springframework.org/schema/aop"
     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/aop http://www.springframework.org/schema/aop/spring-aop.xsd
         http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd">
     
     <!-- 配置自定义扫描包 -->
     <context:component-scan base-package="com.cqvie" />
     
     <!-- 配置视图解析器：如何把 handler 方法返回值解析为实际的物理视图 -->
     <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">
         <property name="prefix" value="/WEB-INF/views/"></property>
         <property name="suffix" value=".jsp"></property>
     </bean>
     
     <!-- 加载静态资源 -->
     <!--  
        default-servlet-handler 将在 SpringMVC 上下文中定义一个 DefaultServletHttpRequestHandler,
        它会对进入 DispatcherServlet 的请求进行筛查, 如果发现是没有经过映射的请求, 就将该请求交由 WEB 应用服务器默认的 
        Servlet 处理. 如果不是静态资源的请求，才由 DispatcherServlet 继续处理

        一般 WEB 应用服务器默认的 Servlet 的名称都是 default.
        若所使用的 WEB 服务器的默认 Servlet 名称不是 default，则需要通过 default-servlet-name 属性显式指定
      -->
     <mvc:default-servlet-handler />
     
     <!-- 避免不能正常访问@RequestMapping链接，通常配置 mvc:annotation-driven 标签 -->
     <mvc:annotation-driven></mvc:annotation-driven>    
     
     <!-- 配置国际化资源文件 -->
     <bean id="messageSource" class="org.springframework.context.support.ResourceBundleMessageSource">
         <property name="basename" value="i18n"></property>
     </bean>
     
</beans>

　　（4）实体类 Department.java 和 Employee.java

package com.cqvie.model;

public class Department {

    private Integer id;
    private String departmentName;
    
    public Department() {}    //不能省略此无参构造方法
    
    public Department(Integer id, String departmentName) {
        this.id = id;
        this.departmentName = departmentName;
    }
    
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getDepartmentName() {
        return departmentName;
    }
    public void setDepartmentName(String departmentName) {
        this.departmentName = departmentName;
    }
}

package com.cqvie.model;

import java.util.Date;

import javax.validation.constraints.Past;

import org.hibernate.validator.constraints.Email;
import org.hibernate.validator.constraints.NotEmpty;
import org.springframework.format.annotation.DateTimeFormat;
import org.springframework.format.annotation.NumberFormat;

public class Employee {

    private Integer id;
    @NotEmpty    //不为空
    private String lastName;
    @Email    //必须为邮件格式
    private String email;
    private int gender;
    @Past    //日期必须小于当前日期
    @DateTimeFormat(pattern = "yyyy-MM-dd")    //日期格式
    private Date birthday;
    @NumberFormat(pattern = "#,###,##.#")//eg:8,456,89.2  输入数字格式
    private Float num;
    private Department department;
    
    public Employee(Integer id, String lastName, String email, int gender, Department department) {
        this.id = id;
        this.lastName = lastName;
        this.email = email;
        this.gender = gender;
        this.department = department;
    }
    
    public Employee() {
    }

    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getLastName() {
        return lastName;
    }
    public void setLastName(String lastName) {
        this.lastName = lastName;
    }
    public String getEmail() {
        return email;
    }
    public void setEmail(String email) {
        this.email = email;
    }
    public int getGender() {
        return gender;
    }
    public void setGender(int gender) {
        this.gender = gender;
    }
    public Department getDepartment() {
        return department;
    }
    public void setDepartment(Department department) {
        this.department = department;
    }
    public Date getBirthday() {
        return birthday;
    }
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
    public Float getNum() {
        return num;
    }
    public void setNum(Float num) {
        this.num = num;
    }

    @Override
    public String toString() {
        return "Employee [id=" + id + ", lastName=" + lastName + ", email=" + email + ", gender=" + gender
                + ", birthday=" + birthday + ", num=" + num + ", department=" + department + "]";
    }

}

　　（5）Dao 类，本实例属于简单模拟数据库操作，并非实际数据库操作

package com.cqvie.dao;

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;

import org.springframework.stereotype.Repository;

import com.cqvie.model.Department;

@Repository
public class DepartmentDao {

    private static Map<Integer, Department> departments = null;
    
    /**
     * 静态资源，模拟数据库操作
     */
    static {
        departments = new HashMap<Integer, Department>();
        departments.put(101, new Department(101, "D-AA"));
        departments.put(102, new Department(102, "D-BB"));
        departments.put(103, new Department(103, "D-CC"));
        departments.put(104, new Department(104, "D-DD"));
        departments.put(105, new Department(105, "D-EE"));
    }
    
    /**
     * 获得全部部门信息
     * @return
     */
    public Collection<Department> getDepartments() {
        return departments.values();
    }
    
    /**
     * 根据ID获取部门
     * @param id
     * @return
     */
    public Department getDepartment(Integer id) {
        return departments.get(id);
    }
}

package com.cqvie.dao;

import java.util.Collection;
import java.util.HashMap;
import java.util.Map;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Repository;

import com.cqvie.model.Department;
import com.cqvie.model.Employee;

@Repository
public class EmployeeDao {

    private static Map<Integer, Employee> employees = null;
    
    @Autowired
    private DepartmentDao departmentDao;
    
    /**
     * 静态资源，模拟数据库数据
     */
    static {
        employees = new HashMap<Integer, Employee>();
        employees.put(1001, new Employee(1001, "E-AA", "[e-mail]", 1, new Department(101, "D-AA")));
        employees.put(1002, new Employee(1002, "E-BB", "[e-mail]", 1, new Department(102, "D-BB")));
        employees.put(1003, new Employee(1003, "E-CC", "[e-mail]", 0, new Department(103, "D-CC")));
        employees.put(1004, new Employee(1004, "E-DD", "[e-mail]", 0, new Department(104, "D-DD")));
        employees.put(1005, new Employee(1005, "E-EE", "[e-mail]", 1, new Department(105, "D-EE")));
    }
    
    private static Integer initId = 1006;
    
    /**
     * 保存信息
     * @param employee
     */
    public void save(Employee employee) {
        if(employee.getId() == null) {
            employee.setId(initId ++); 
        }
        employee.setDepartment(departmentDao.getDepartment(employee.getDepartment().getId()));
        employees.put(employee.getId(), employee);
    }
    
    /**
     * 获得全部信息
     * @return
     */
    public Collection<Employee> getAll() {
        return employees.values();
    }
    
    /**
     * 根据ID获取信息
     */
    public Employee get(Integer id) {
        return employees.get(id);
    }
    
    /**
     * 根据ID删除该信息
     * @param id
     */
    public void delete(Integer id) {
        employees.remove(id);
    }
}

　　（6）Handler 及控制层代码 EmployeeHandler.java

package com.cqvie.handler;

import java.util.Map;

import javax.validation.Valid;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.validation.Errors;
import org.springframework.validation.FieldError;
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 org.springframework.web.bind.annotation.RequestParam;

import com.cqvie.dao.DepartmentDao;
import com.cqvie.dao.EmployeeDao;
import com.cqvie.model.Employee;

@Controller
public class EmployeeHandler {

    @Autowired
    private EmployeeDao employeeDao;
    @Autowired
    private DepartmentDao departmentDao;
    
    /**
     * 显示所有用户
     * @param map
     * @return
     */
    @RequestMapping("/emps")
    public String list(Map<String, Object> map) {
        map.put("employees", employeeDao.getAll());
        System.out.println("****list*****");
        return "list";
    }
    
    /**
     * 输入信息页面
     * @param map
     * @return
     */
    @RequestMapping(value = "/emp")
    public String input(Map<String, Object> map) {
        map.put("dapartments", departmentDao.getDepartments());
        map.put("employee", new Employee());// employee 和 input.jsp 页面的 modelAttribute="employee" 值一致
        System.out.println("****input*****");
        return "input";
    }
    
    /**
     * 保存用户
     * @param employee
     * @param result
     * @param map
     * @return
     */
    @RequestMapping(value = "/emp-save", method = {RequestMethod.POST})
    public String save(@Valid Employee employee, Errors result, Map<String, Object> map) {
        
        if(result.getErrorCount() > 0) {
            System.err.println("*********************出错了！*********************");
            for(FieldError error: result.getFieldErrors()) {
                System.err.println(error.getField() + "：" + error.getDefaultMessage());
            }
            map.put("dapartments", departmentDao.getDepartments());
            return "input";
        }
        
        employeeDao.save(employee);
        System.out.println("****save*****");
        System.out.println(employee);
        return "redirect:/emps";
    }
    
    /**
     * 删除用户
     * @param id
     * @return
     */
    @RequestMapping(value = "/emp-del/{id}", method = RequestMethod.DELETE)
    public String delete(@PathVariable("id") Integer id) {
        employeeDao.delete(id);
        System.out.println("*****delete******");
        return "redirect:/emps";
    }
    
    /**
     * 修改用户页面
     * @param id
     * @param map
     * @return
     */
    @RequestMapping(value = "/emp-update-input/{id}", method = RequestMethod.GET)
    public String inputUpdate(@PathVariable("id") Integer id, Map<String, Object> map) {
        map.put("employee", employeeDao.get(id));// employee 和 input.jsp 页面的 modelAttribute="employee" 值一致    
        map.put("dapartments", departmentDao.getDepartments());
        return "input";
    }
    /**
     * 修改用户
     * @param employee
     * @return
     */
    @RequestMapping(value = "emp-save", method = RequestMethod.PUT)
    public String update(Employee employee) {
        employeeDao.save(employee);
        System.out.println("*****update******");
        return "redirect:/emps";
    }
    @ModelAttribute
    public void getEmployee(@RequestParam(value = "id", required = false) Integer id,
            Map<String, Object> map) {
        if(id != null) {
            map.put("employee", employeeDao.get(id));
        }
    }
}

　　（7）显示界面 list.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>
<!--  
    SpringMVC 处理静态资源:
    1. 为什么会有这样的问题:
    优雅的 REST 风格的资源URL 不希望带 .html 或 .do 等后缀
    若将 DispatcherServlet 请求映射配置为 /, 
    则 Spring MVC 将捕获 WEB 容器的所有请求, 包括静态资源的请求, SpringMVC 会将他们当成一个普通请求处理, 
    因找不到对应处理器将导致错误。
    2. 解决: 在 SpringMVC 的配置文件中配置 <mvc:default-servlet-handler/>
-->
<head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>首页</title>
    <script type="text/javascript" src="js/jquery.js"></script>
    <script type="text/javascript">
        $(function() {
            $(".delete").click(function() {
                var name = $(this).next(":input").val();
                var result = confirm("确认要删除 " + name + " 的信息吗？");
                if(result == true) {
                    var href = $(this).attr("href");
                    $("form").attr("action", href).submit();
                } 
                return false;
            });
        });
    </script>
</head>
<body>
    <c:if test="${empty requestScope.employees}">
        没有任何员工信息。
    </c:if>
    <c:if test="${!empty requestScope.employees}">
        <table border="1" cellpadding="10" cellspacing="0">
            <tr>
                <th>ID</th>
                <th>LastName</th>
                <th>E-mail</th>
                <th>Gender</th>
                <th>Department</th>
                <th>Edit</th>
                <th>Delete</th>
            </tr>
            <c:forEach items="${requestScope.employees }" var="emp">
                <tr>
                    <td>${emp.id }</td>
                    <td>${emp.lastName }</td>
                    <td>${emp.email }</td>
                    <td>${emp.gender == 0 ? 'Female' : 'Male'}</td>
                    <td>${emp.department.departmentName }</td>
                    <td>
                        <a href="emp-update-input/${emp.id}">Edit</a>
                    </td>
                    <td>
                        <a class="delete" href="emp-del/${emp.id}">Delete</a>
                        <input type="hidden" value="${emp.lastName}" />
                    </td>
                </tr>
            </c:forEach>
        </table>
    </c:if>
    <hr>
    <a href="emp">Add New Employee</a>
    <form action="" method="post">
        <input type="hidden" name="_method" value="DELETE">
    </form>
</body>
</html>

　　（8）增加用户和修改用户界面 input.jsp

<%@page import="java.util.HashMap"%>
<%@page import="java.util.Map"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%
    Map<String, Object> genders = new HashMap<String, Object>();
    genders.put("1", "Male");
    genders.put("0", "Female");
    request.setAttribute("genders", genders);
%>
<!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>
    <!-- 
        可以通过 modelAttribute 属性指定绑定的模型属性，
        若没有指定该属性，则默认从 request 域对象中读取 command 的表单 bean，
        如果该属性值也不存在，则会发生错误
     -->
    <form:form action="${pageContext.request.contextPath}/emp-save" method="post" modelAttribute="employee">
        <form:errors path="*"></form:errors><br>
        <c:if test="${employee.id == null}">
            <!-- path 属性对应 HTML 表单标签的 name 属性 -->
            LastName：<form:input path="lastName"/>
            <form:errors path="lastName"></form:errors>
        </c:if>
        <c:if test="${employee.id != null}">
            <form:hidden path="id"/>
            <input type="hidden" name="_method" value="PUT">
        </c:if>
        <br>
        Email：<form:input path="email"/>
        <form:errors path="email"></form:errors> <br>
        Gender：<form:radiobuttons path="gender" items="${genders}"/> <br>
        Birthday：<form:input path="birthday"/>
        <form:errors path="birthday"></form:errors>   <br>
        Number：<form:input path="num"/> <br>
        Department：<form:select path="department.id" items="${dapartments}" itemLabel="departmentName" itemValue="id"></form:select><br>
        <input type="submit" value="Submit">
    </form:form>
    
</body>
</html>

　　（9）国际化资源文件 i18n.properties 配置，本例用户 JSR303 数据校验自定义提示错误语言

NotEmpty.employee.lastName = LastName \u4E0D\u80FD\u4E3A\u7A7A
Email.employee.email = Email \u4E0D\u662F\u5408\u6CD5\u90AE\u7BB1
Past.employee.birthday = Birthday \u4E0D\u80FD\u662F\u4E00\u4E2A\u5C06\u6765\u7684\u65F6\u95F4
typeMismatch.employee.birthday = Birthday \u4E0D\u662F\u4E00\u4E2A\u5408\u6CD5\u7684\u65E5\u671F

使用SpringMVC RESTful 架构实现简单的 CRUD 操作到此就结束了，欢迎大家提问纠错。