REST:Representational State Transfer,表现层资源状态转移
资源:资源是一种看待服务器的方式
资源的表述:资源的表述是资源在某个特定时刻的状态的描述。可以在客户端-服务器端之间转移、交换。
状态转移:在客户端和服务器端之间转移(transfer)代表资源状态的描述,通过转移和操作资源的表述,来间接实现操作资源的目的。
说人话就是统一资源相同但操作不同的请求的请求路径,如getUserById和DeleteUserByName都设置资源路径为User
即:相同的请求路径、不同的请求方式表示不同的操作
在Http协议中四个表示操作方式的动词:GET、Post、Put、Delete
传统方式
RESTFul方式
查询
findAllUser
/user
get
id查询
getUserById?id=1
/user/1
get
添加
saveUser
/user
post
修改
updateUser
/user
put
删除
deleteUser
/user
delete
@RequestMapping(value = "/user", method = RequestMethod.GET)
public String getAllUser() {
System.out.println("查询所有用户信息");
return "success";
}
@RequestMapping(value = "/user/{id}", method = RequestMethod.GET)
public String getUserById(@PathVariable("id") Integer id) {
System.out.println("根据id" + String.valueOf(id) +"查询所有用户信息");
return "success";
}
@RequestMapping(value = "/user", method = RequestMethod.POST)
public String addUser(@RequestParam("username") String username,
@RequestParam("password") String password) {
System.out.println("添加用户信息:" + username + "," + password);
return "success";
}
<a th:href="@{/user}">查询所有用户信息</a><br>
<a th:href="@{/user/1}">查询id为1的用户信息</a><br>
<form th:action="@{/user}" method="post">
UserName:<input type="text"name="username" value="宇多田光"><br>
Password:<input type="password"name="password" value="admin123"><br>
<input type="submit"><br>
</form>
form表单中的method方法设置为Post或者Delete是不起作用的,可以通过过滤器替换request请求的方法实现Put和Delete
<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>
根据源码,实现请求方式转换需要有两个条件:
①请求方式为post
②必须传输一个name为_method值为put或者delete的请求参数
<form th:action="@{/user}" method="post">
<input type="hidden" name="_method" value="put">
UserName:<input type="text"name="username" value="宇多田光"><br>
Password:<input type="password"name="password" value="admin123"><br>
<input type="submit"><br>
console:
修改用户信息:宇多田光,admin123
CharacterEncodingFilter过滤器设置编码的前提条件是在此之前不能获取任何的请求参数,而HiddenHttpMethodFilter获取了name为_method的请求参数,因此CharacterEncodingFilter的< Filter-mapping > 要放在HiddenMethodFilter之前
通过请求方式实现Employee的增删改查
RESTFul方式
查询
/employee
get
id查询
/employee/1
get
添加
/employee
post
修改
/employee
put
删除
/employee/1
delete
<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<table id="dataTable" border="1" cellspacing="0" cellpadding="0" style="text-align: center">
<tr>
<th colspan="5">Employee Information</th>
</tr>
<tr>
<td>Id</td>
<td>LastName</td>
<td>Email</td>
<td>Gender</td>
<td>Option</td>
</tr>
<tr th:each="employee : ${employeelist}">
<td th:text="${employee.id}"></td>
<td th:text="${employee.lastName}"></td>
<td th:text="${employee.email}"></td>
<td th:text="${employee.gender}"></td>
<td>
<a @click="deleteEmployee" th:href="@{/employee/} + ${employee.id}">delete</a>
<a th:href="@{/employee/} + ${employee.id}">update</a>
</td>
</tr>
</table>
<form method="post" id="deleteForm">
<input name="_method" type="hidden" value="delete">
</form>
<a th:href="@{/add}">添加</a>
<script type="text/javascript" th:src="@{/static/js/vue.js}"></script>
<script type="text/javascript">
var vue = new Vue({
el: "#dataTable",
methods:{
deleteEmployee:function (event) {
console.log("HELLO")
var deleteFrom = document.getElementById("deleteForm");
//将触发点事件的href属性赋值给deleteform表单的action
deleteFrom.action = event.target.href;
//表单提交
deleteFrom.submit();
//取消超链接的默认行为
event.preventDefault();
}
}
});
</script>
</body>
</html>
/employee(请求) (GET) --> getAllEmploye(控制器方法) --> employee_list(前端页面)
@RequestMapping(value = "/employee", method = RequestMethod.GET)
public String getAllEmployee(Model model) {
Collection<Employee> employeelist = employeeDao.getAll();
model.addAttribute("employeelist", employeelist);
return "employee_list";
}
①首先通过在SpringMVC.xml配置文件设置视图控制器实现/employee请求和getAllEmploye控制器方法的映射
②通过DAO获取employeelist并将其添加到request域中
③通过ThymeLeaf视图转发到前端页面employee_list.html
④在前端页面通过ThymeLeaf获取request域中的employeelist并渲染显示
/employee/{id} (DELETE) --> DeleteEmployeeById --> "redirect:/employee"
@RequestMapping(value = "/employee/{id}", method = RequestMethod.DELETE)
public String DeleteEmployeeById(@PathVariable("id") Integer id) {
employeeDao.delete(id);
return "redirect:/employee";
}
①这里前端页面的删除是一个超链接,其内容经过Thymeleaf渲染后为 /employyee/1的形式而超链接默认只能通过get发送请求,因此直接点击会被当成“根据ID进行查询”的操作
<a @click="deleteEmployee" th:href="@{/employee/} + ${employee.id}">delete</a>
解决办法是使用Vue,通过给超链接添加一个点击事件,当用户点击时将点击事件的请求地址(/employyee/1)赋值给一个带有隐藏域的form表单的action,提交表单并且禁用点击事件的默认行为,最终服务器的过滤器组件HiddenHttpMethodFilter会将表单的post请求更改为delete请求。
转换请求方式用的deleteForm表单
<form method="post" id="deleteForm">
<input name="_method" type="hidden" value="delete">
</form>
Vue实现转移事件
<script type="text/javascript" th:src="@{/static/js/vue.js}"></script>
<script type="text/javascript">
var vue = new Vue({
el: "#dataTable",
methods:{
deleteEmployee:function (event) {
console.log("HELLO")
var deleteFrom = document.getElementById("deleteForm");
//将触发点事件的href属性赋值给deleteform表单的action
deleteFrom.action = event.target.href;
//表单提交
deleteFrom.submit();
//取消超链接的默认行为
event.preventDefault();
}
}
});
</script>
如此一来就得到了一个请求路径为"/employee/1",请求方式为"Delete"的request
③通过DAO实现根据id删除
④重定向到/employee请求,这里使用转发"employee_list"到前端页面的话,request是没有页面需要的内容的,因此需要重定向到请求/employee,经控制器方法向请求域添加employeelist才能使前端获取到数据
/employee/{id} (GET) --> toUpdateEmployee --> "employee_update"
/employee (POST-->PUT) --> UpdateEmployee --> "redirect:/employee"
①通过前端超链接点击的GET方式的请求,经ThymeLeaf渲染的请求路径为 /employee/id,然后经控制器方法toUpdateEmployee通过DAO根据id获取到Employee对象,然后向request域中添加此对象转发至前端页面employee_update
<a th:href="@{/employee/} + ${employee.id}">update</a>
@RequestMapping(value = "/employee/{id}", method = RequestMethod.GET)
public String toUpdateEmployee(Model model,
@PathVariable("id") Integer id) {
Employee employee = employeeDao.get(id);
model.addAttribute("employee", employee);
return "employee_update";
}
②前端页面employee_update根据request域中的内容通过ThymeLeaf进行渲染回显
<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<div style="border: cornflowerblue 1px solid">
<form th:action="@{/employee}" method="post">
<input type="hidden" name="_method" value="put">
编号:<input type="text" name="id" th:value="${employee.id}"><br>
姓名:<input type="text" name="lastName" th:value="${employee.lastName}"><br>
邮箱:<input type="text" name="email" th:value="${employee.email}"><br>
性别:<input type="text" name="gender" th:value="${employee.gender}"><br>
<input type="submit" value="修改">
</form>
</div>
</body>
</html>
③employee_update表单提交请求地址为 /employee请求方式为POST的request请求,因表单含有"_mothod"隐藏域,因此会服务器过滤器修改请求方式为PUT
④该请求会被被控制器方法UpdateEmployee匹配,经DAO修改后重定向到/employee请求
@RequestMapping(value = "/employee", method = RequestMethod.PUT)
public String UpdateEmployee(Employee employee) {
employeeDao.save(employee);
return "redirect:/employee";
}
employee_list.html
<a th:href="@{/add}">添加</a>
springMVC.xml
<mvc:view-controller path="/add" view-name="employee_add"></mvc:view-controller>
employee_add.html
<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<div style="border: cornflowerblue 1px solid">
<form th:action="@{/employee}" method="post">
编号:<input type="text" name="id"><br>
姓名:<input type="text" name="lastName" value="宇多田光"><br>
邮箱:<input type="text" name="email" value="hikaru@163.com"><br>
性别:<input type="text" name="gender" value="1"><br>
<input type="submit" value="添加">
</form>
</div>
</body>
</html>
AddEmployee()
@RequestMapping(value = "/employee", method = RequestMethod.POST)
public String AddEmployee(Employee employee) {
employeeDao.save(employee);
return "redirect:/employee";
}
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