SpringMVC 学习笔记(五) 基于RESTful的CRUD
1.1. 概述
当提交的表单带有_method字段时,通过HiddenHttpMethodFilter 将 POST 请求转换成 DELETE、PUT请求,加上@PathVariable注解从而实现 RESTful 风格的CRUD
1.2. 配置信息
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" version="3.0" > <!-- 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> <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> <!--配置 HiddenHttpMethodFilter 能够将 POST 请求转为 DELETE、PUT 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> </web-app>
1.3. 效果
① 通过POST 请求添加员工信息
② 通过PUT 请求改动员工信息
③ 通过DELETE 请求删除员工信息
④ 通过GET 请求 获取全部的 员工信息
1.4. 代码
Employee.java
package com.ibigsea.springmvc.model; public class Employee { private Integer id; private String name; private String email; private int sex; private Department department; public Employee(Integer id, String name, String email, int sex, Department department) { super(); this.id = id; this.name = name; this.email = email; this.sex = sex; this.department = department; } public Employee() { super(); } public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } public int getSex() { return sex; } public void setSex(int sex) { this.sex = sex; } public Department getDepartment() { return department; } public void setDepartment(Department department) { this.department = department; } @Override public String toString() { return "Employee [id=" + id + ", name=" + name + ", email=" + email + ", sex=" + sex + ", department=" + department + "]"; } }
Department.java
package com.ibigsea.springmvc.model; import java.io.Serializable; public class Department implements Serializable { private static final long serialVersionUID = 6881984318733090395L; private Integer id; private String name; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } @Override public String toString() { return "Department [id=" + id + ", name=" + name + "]"; } }
RestfulController.java
package com.ibigsea.springmvc.rest; import java.util.Map; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Controller; 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.ibigsea.springmvc.dao.DepartmentDao; import com.ibigsea.springmvc.dao.EmployeeDao; import com.ibigsea.springmvc.model.Employee; /** * 基于Restful风格的增删改查 * @author bigsea */ @Controller @RequestMapping("/restful") public class RestfulController { @Autowired private EmployeeDao employeeDao; @Autowired private DepartmentDao departmentDao; /** * 由于改动的时候不能改动员工姓名, * 所以通过 @ModelAttribute 注解, * 表示在运行目标方法时,先获取该员工对象 * 将员工对象存入 implicitMode 中 * @param id 员工ID * @param map 实际传入的是implicitMode */ @ModelAttribute public void getEmployee(@RequestParam(value="id",required=false) Integer id,Map<String,Object> map){ if (id != null) { map.put("employee", employeeDao.getEmpById(id)); } } /** * 查看全部的员工信息 * @param map * @return */ @RequestMapping("/list") public String list(Map<String, Object> map){ map.put("emps", employeeDao.getAll()); return "list"; } /** * 跳转到员工加入页面 * @param map * @return */ @RequestMapping(value="/add",method=RequestMethod.GET) public String add(Map<String, Object> map){ map.put("depts", departmentDao.getAll()); map.put("action", "add"); return "emp"; } /** * 加入员工 * @param emp * @return */ @RequestMapping(value="/add",method=RequestMethod.POST) public String add(Employee emp){ if (emp == null) { return "emp"; } if (emp.getDepartment().getId() != null) { emp.setDepartment(departmentDao.getDepartmentById(emp.getDepartment().getId())); } employeeDao.save(emp); return "redirect:/restful/list"; } /** * 删除员工信息 * @param id * @return */ @RequestMapping(value="/delete/{id}",method=RequestMethod.DELETE) public String delete(@PathVariable("id") Integer id){ employeeDao.delEmpById(id); return "redirect:/restful/list"; } /** * 由于先运行了 @ModelAttribute 注解的方法, * 获取了该员工ID所相应的员工信息 * 然后在将前台获取的员工数据存入获取的员工信息中, * 这样就不用提交name属性也能够获取到值 * @param emp * @return */ @RequestMapping(value="/edit",method=RequestMethod.PUT) public String edit(Employee emp){ if (emp == null) { return "emp"; } if (emp.getDepartment().getId() != null) { emp.setDepartment(departmentDao.getDepartmentById(emp.getDepartment().getId())); } employeeDao.save(emp); return "redirect:/restful/list"; } /** * 跳转到员工改动页面 * @param id 员工ID * @param map implicitMode * @return */ @RequestMapping(value="/edit/{id}",method=RequestMethod.GET) public String edit(@PathVariable("id") Integer id,Map<String, Object> map){ map.put("emp", employeeDao.getEmpById(id)); map.put("depts", departmentDao.getAll()); map.put("action", "edit"); return "emp"; } }
EmployeeDao.java
package com.ibigsea.springmvc.dao; import java.util.Collection; import java.util.HashMap; import java.util.Map; import org.springframework.stereotype.Component; import com.ibigsea.springmvc.model.Department; import com.ibigsea.springmvc.model.Employee; @Component public class EmployeeDao { private static Map<Integer,Employee> emps = new HashMap<Integer, Employee>(); /** * 初始化员工信息 */ static { emps.put(1001, new Employee(1001,"AA","AA@ibigsea.com",0,new Department(101, "JAVA"))); emps.put(1002, new Employee(1002,"BB","BB@ibigsea.com",0,new Department(102, ".NET"))); emps.put(1003, new Employee(1003,"CC","CC@ibigsea.com",1,new Department(103, "PHP"))); emps.put(1004, new Employee(1004,"DD","DD@ibigsea.com",0,new Department(104, "C"))); } private static int employeeId = 1005; /** * 保存员工信息 * @param emp */ public void save(Employee emp){ if (emp.getId() == null) { emp.setId(employeeId++); } emps.put(emp.getId(), emp); } /** * 获取全部的员工信息 * @return */ public Collection<Employee> getAll(){ return emps.values(); } /** * 依据ID获取员工信息 * @param id * @return */ public Employee getEmpById(Integer id){ return emps.get(id); } /** * 依据ID删除员工信息 * @param id */ public void delEmpById(Integer id){ emps.remove(id); } }
DepartmentDao.java
package com.ibigsea.springmvc.dao; import java.util.Collection; import java.util.HashMap; import java.util.Map; import org.springframework.stereotype.Component; import com.ibigsea.springmvc.model.Department; @Component public class DepartmentDao { public static Map<Integer, Department> depts = new HashMap<Integer, Department>(); /** * 初始化部门信息 */ static { depts.put(101, new Department(101,"JAVA")); depts.put(102, new Department(102,".NET")); depts.put(103, new Department(103,"PHP")); depts.put(104, new Department(104,"C")); } /** * 获取全部的部门信息 * @return */ public Collection<Department> getAll(){ return depts.values(); } /** * 依据ID获取部门信息 * @param id * @return */ public Department getDepartmentById(Integer id){ return depts.get(id); } }
List.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %> <!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>员工信息</title> </head> <body> <c:if test="${ empty emps }"> 没有员工信息 </c:if> <c:if test="${ !empty emps }"> <table border="1" bordercolor="black" cellspacing="0"> <tr> <td width="40px">id</td> <td width="30px">name</td> <td width="80px">email</td> <td width="30px">sex</td> <td width="40px">编辑</td> <td width="40px">删除</td> </tr> <c:forEach items="${emps }" var="emp"> <tr> <td>${emp.id }</td> <td>${emp.name }</td> <td>${emp.email }</td> <td>${emp.sex == 0 ? '男' : '女'}</td> <td><a href="${pageContext.request.contextPath}/restful/edit/${emp.id }">Edit</a></td> <td><form action="${pageContext.request.contextPath}/restful/delete/${emp.id }" method="post"> <input type="hidden" name="_method" value="DELETE"> <input type="submit" value="Delete"> </form> </td> </tr> </c:forEach> </table> </c:if> <br><br> <a href="${pageContext.request.contextPath}/restful/add">加入员工</a> </body> </html>
Emp.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %> <!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>员工信息</title> </head> <body> <form action="${pageContext.request.contextPath}/restful/${action}" method="post"> <c:if test="${!empty emp}"> <input type="hidden" name="_method" value="PUT"> <input type="hidden" name="id" value="${emp.id }"><br/><br/> </c:if> <c:if test="${empty emp}">name : <input type="text" name="name" value="${emp.name }"><br/><br/></c:if> email : <input type="text" name="email" value="${emp.email }"><br/><br/> sex :<input type="radio" name="sex" value="0" <c:if test="${emp.sex == 0}">checked</c:if>>男 <input type="radio" name="sex" value="1" <c:if test="${emp.sex == 1}">checked</c:if>>女<br/><br/> department :<select name="department.id"> <c:forEach items="${depts }" var="dept"> <option value="${dept.id }" <c:if test="${emp.department.id == dept.id}">selected</c:if>>${dept.name }</option> </c:forEach> </select> <br><br/> <input type="submit" value="提交"> </form> </body> </html>
1.5. 静态资源问题
由于配置了DispatcherServlet而且拦截了全部的请求,所以在加入静态资源的时候会訪问不到静态资源,在springMVC.xml配置
mvc: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,假设发现是没有经过映射的请求,就将该请求交由 WEB应用server默认的 Servlet 处理。假设不是静态资源的请求。才由DispatcherServlet 继续处理
mvc:annotation-driven
会自己主动注冊
RequestMappingHandlerMapping
RequestMappingHandlerAdapter
ExceptionHandlerExceptionResolver 三个bean。
就能訪问到静态资源了
1.6. mvc:annotation-driven和mvc:default-servlet-handler
在配置SpringMVC配置文件时加入mvc:annotation-driven
<mvc:annotation-driven /> 会自己主动注冊三个Bean
² RequestMappingHandlerMapping
² RequestMappingHandlerAdapter
² ExceptionHandlerExceptionResolver
还将提供下面支持:
– 支持使用 ConversionService 实例对表单參数进行类型转换
– 支持使用 @NumberFormat 、@DateTimeFormat注解完毕数据类型的格式化
– 支持使用 @Valid 注解对 JavaBean 实例进行 JSR 303 验证
– 支持使用 @RequestBody 和 @ResponseBody 注解