• SpringMVC----RESTFUL_CRUD_修改操作


    1.注意:

    <!--    对于_method不能使用form:hidden标签,因为modelAttribute对应的bean中没有_method这个属性,应该使用input标签 -->
     <!-- <form:hidden path="_method" value="PUT"/>     -->

    2.代码:

    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>
    <head>
    <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
    <title>Insert title here</title>
    <!-- SpringMVC处理静态资源
        1.为什么会有这种问题?
            优雅的REST风格的资源URL不希望带.html或.do等后缀;
            若将DispatcherServlet请求映射为/,则springMVC将捕获WEB容器的所有请求,包括静态资源(图片、css、js)的请求,springMVC会将
            他们当成一个普通请求处理,因此找不到对应的处理器将导致错误
        2.如何解决:
            在springMVC的配置文件中配置:<mvc:default-servlet-handler/>的方式解决静态资源的问题
     -->
    <script type="text/javascript" src="scripts/jquery-1.9.1.min.js"></script>
    <script type="text/javascript">
        $(function() {
            $(".delete").click(function() {
                var href = $(this).attr("href");
                $("form").attr("action", href).submit();
                return false;
            });
        })
    </script>
    </head>
    <body>
    
        <form action="" method="POST">
            <input type="hidden" name="_method" value="DELETE" />
        </form>
    
    
        <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>Email</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/${emp.id}">Edit</a></td>
                        <!-- 默认超链接是一个GET请求,但是使用HiddenHttpMethodFilter后POST请求才能转换成DELETE请求(借助js实现) -->
                        <td><a class="delete" href="emp/${emp.id}">Delete</a></td>
                    </tr>
                </c:forEach>
            </table>
        </c:if>
        <br>
        <br>
    
        <a href="emp">Add New Employee</a>
    </body>
    </html>
    
    
    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"%>
    <!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>
        <!-- why使用form标签
                1.可以更快速的开发出表单页面,而且可以更加方便的进行表单值的回显;
         -->
    
        <form:form action="${pageContext.request.contextPath}/emp"
            method="POST" modelAttribute="employee">
    
            <c:if test="${employee.id == null}">
                <!-- path属性对应html表单标签的name属性值 -->
                LastName:<form:input path="lastName" />
            </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" />
            <br>
            <%
                Map<String, String> genders = new HashMap();
                    genders.put("1", "male");
                    genders.put("0", "Female");
    
                    request.setAttribute("genders", genders);
            %>
            <!-- delimiter="<br>" 按照br分割 -->
            gender:<form:radiobuttons path="gender" items="${genders}" />
            <br>
            Department:<form:select path="department.id" items="${departments}"
                itemLabel="departmentName" itemValue="id"></form:select>
            <br>
            <input type="submit" value="submit" />
        </form:form>
    </body>
    </html>
    
    
    java代码:
    
    package com.yikuan.springmvc.crud.handlers;
    
    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.yikuan.springmvc.crud.dao.DepartmentDao;
    import com.yikuan.springmvc.crud.dao.EmployeeDao;
    import com.yikuan.springmvc.crud.entities.Employee;
    
    @Controller
    public class EmployeeHandler {
        
        @Autowired
        private EmployeeDao employeeDao;
        
        @Autowired
        private DepartmentDao departmentDao;
        
        @ModelAttribute
        public void getEmployee(@RequestParam(value="id",required=false)Integer id,
                Map<String,Object> map){
            if(id != null){
                map.put("employee", employeeDao.get(id));
            }
        }
        
        @RequestMapping(value="/emp",method=RequestMethod.PUT)
        public String update(Employee employee){
            employeeDao.save(employee);    //此时修改完后,lastName为null@ModelAttribute;
            return "redirect:/emps";
        }
        
        @RequestMapping(value="/emp/{id}",method=RequestMethod.GET)
        public String input(@PathVariable("id") Integer id,Map<String,Object> map){
            map.put("employee", employeeDao.get(id));
            /*employee必须和input.jsp中表单页面的modelAttribute="employee"值一样*/
            map.put("departments", departmentDao.getDepartments());
            return "input";
        }
        
        
        @RequestMapping(value="/emp/{id}",method=RequestMethod.DELETE)
        public String delete(@PathVariable("id") Integer id){
            employeeDao.delete(id);
            return "redirect:/emps";
        }
        
        
        @RequestMapping(value="/emp",method=RequestMethod.POST)
        public String save(Employee employee){
            employeeDao.save(employee);
            return "redirect:/emps";
        }
        
        
        @RequestMapping(value="emp",method=RequestMethod.GET)
        public String input(Map<String,Object> map){
            map.put("departments", departmentDao.getDepartments());
            map.put("employee", new Employee());
            return "input";
        }
        
        @RequestMapping("/emps")
        public String list(Map<String, Object> map){
            map.put("employees", employeeDao.getAll());
            return "list";
        }
    }
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  • 原文地址:https://www.cnblogs.com/yikuan-919/p/9741153.html
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