SpringMvc-Restful

一、RESTFUL

redtful是一种软件架构的风格，当传输值时不再用？传参，而是用/进行传参。

使用REDTFUL模拟用户资源（增、删、改、查）

先写查询和增加操作

testController中：

@Controller
public class UserController {// /user Get 查询用户所有信息// /user/1  Get 根据id查询用户所有信息//  /user  Post  添加用户信息//  /user/1  Delete 删除用户信息//  /user  Put  修改用户信息//查询用户@RequestMapping(value = "/user",method = RequestMethod.GET)public String GetAllUser(){System.out.println("获取所有用户信息");return "hi";}//根据id查询用户@RequestMapping(value = "/user/{id}",method = RequestMethod.GET)public String GetUserById(){System.out.println("根据id获取用户信息");return "hi";}//添加用户信息@RequestMapping(value = "/user",method = RequestMethod.POST)public String InsertUser((String username,String password){System.out.println("添加用户信息");return "hi";}
}

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head><meta charset="UTF-8"><title>Title</title>
</head>
<body>
<h1>首页</h1>
<a th:href="@{/user}">获取用户所有信息</a>
<a th:href="@{/user/1}">根据用户id获取信息</a>
<form th:action="@{/user}" method="post">用户名：<input type="text" name="username"><br>密码：<input type="password" name="password"><br><input type="submit" value="提交">
</form>
</body>
</html>

注：Put和Delete请求，要配置HiddenHttpMethodFilter过滤器才能使用

在web.xml中添加HiddenHttpMethodFilter过滤器：

 <!--配置HiddenHttpMethodFilter--><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>

修改用户信息

@Controller
public class UserController {// /user Get 查询用户所有信息// /user/1  Get 根据id查询用户所有信息//  /user  Post  添加用户信息//  /user/1  Delete 删除用户信息//  /user  Put  修改用户信息
//修改用户信息@RequestMapping(value = "/user",method = RequestMethod.PUT)public String updateUser(String username,String password){System.out.println("username:"+username+",password:"+password);System.out.println("修改用户信息");return "hi";}
}

<form th:action="@{/user}" method="post"><input type="hidden" name="_method" value="PUT">用户名：<input type="text" name="username"><br>密码：<input type="password" name="password"><br><input type="submit" value="修改">
</form>

案例

要满足删除操作，需要有表单提交，Post请求方式，还有HiddenHttpMethodFilter过滤器,还有配合使用前端的vue.js，要引入vue.js，编写<script></script>，进行删除操作的具体描述。

引入vue之后，在spring.xml中还需配置开放对静态资源的访问。

静态资源：先对DispatcherServlet进行处理，如果在匹配请求时，没有找到请求映射，那当前的请求就会被defaultservlet处理。

因为删除操作设计vue.js所以只在上面作为说明，下面为增删改。

框架：

先创建bean和dao对象：

package com.pon.bean;
public class Employee {private Integer id;private String lastName;private String email;private Integer gender;public Employee() {}public Employee(Integer id, String lastName, String email, Integer gender) {this.id = id;this.lastName = lastName;this.email = email;this.gender = gender;}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 Integer getGender() {return gender;}public void setGender(Integer gender) {this.gender = gender;}@Overridepublic String toString() {return "Employee{" +"id=" + id +", lastName='" + lastName + '\'' +", email='" + email + '\'' +", gender=" + gender +'}';}
}

package com.pon.dao;
import com.pon.bean.Employee;
import org.springframework.stereotype.Repository;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
@Repository
public class EmployeeDao {private static Map<Integer, Employee> employeees=null;static {employeees=new HashMap<Integer,Employee>();employeees.put(1001,new Employee(1001,"E-AA","AA@163.com",1));employeees.put(1002,new Employee(1002,"E-BB","BB@163.com",1));employeees.put(1003,new Employee(1003,"E-CC","CC@163.com",0));employeees.put(1004,new Employee(1004,"E-DD","DD@163.com",0));employeees.put(1005,new Employee(1005,"E-EE","EE@163.com",1));}private static Integer initId=1006;public void save(Employee employee){if(employee.getId()==null){employee.setId(initId++);}employeees.put(employee.getId(),employee);}public Collection<Employee> getAll(){return employeees.values();}public Employee get(Integer id){return employeees.get(id);}public void delete(Integer id){employeees.remove(id);}
}

创建EemployeeController:

package com.pon.controller;
import com.pon.bean.Employee;
import com.pon.dao.EmployeeDao;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import java.util.Collection;@Controller
public class EmployeeController {@Autowiredprivate EmployeeDao employeeDao;@RequestMapping("/")public String First(){return "index";}@GetMapping("/employee")public String GetAllInfo(Model model){//用域对象来获取对象Collection<Employee> employeeList= employeeDao.getAll();model.addAttribute("employeeList",employeeList);return "employee_list";}@RequestMapping("/toAdd")public String Toadd(){return "toadd";}@RequestMapping(value = "/employee",method = RequestMethod.POST)public String AddUser(Employee employee){employeeDao.save(employee);return "redirect:/employee";}//要想实现更新功能，先要查询到此id下并让他回显@RequestMapping(value = "/employee/{id}",method = RequestMethod.GET)public String SelectUser(@PathVariable Integer id, Model model){Employee employee= employeeDao.get(id);model.addAttribute("employee",employee);return "select";}//更新@RequestMapping(value = "/employee",method = RequestMethod.PUT)public String UpdateUser(Employee employee){employeeDao.save(employee);return "redirect:/employee";}}

首页index.html:

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head><meta charset="UTF-8"><title>Title</title>
</head>
<body>
<h1>首页</h1>
<a th:href="@{/employee}">查询全部信息</a>
</body>
</html>

用表格来展示写的信息employee_list.html:

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head><meta charset="UTF-8"><title>Employee</title>
</head>
<body>
<!--用表格来表示数据-->
<table><tr><th>id</th><th>lastName</th><th>email</th><th>gender</th><th>options <a th:href="@{/toAdd}">(添加)</a> </th></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="${employee.gender}"></td><td><a th:href="@{'/employee/'+${employee.id}}">delete</a><a th:href="@{'/employee/'+${employee.id}}">update</a></td></tr>
</table>
</body>
</html>

添加页面toadd.html：

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head><meta charset="UTF-8"><title>Title</title>
</head>
<body>
<form th:action="@{/employee}" method="post">lastName:<input type="text" name="lastName"><br>email:<input type="text" name="email"><br>gender:<input type="radio" name="gender" value="1">男<input type="radio" name="gender" value="0">女<br><input type="submit" value="添加">
</form>
</body>
</html>

修改页面select.html:

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head><meta charset="UTF-8"><title>Title</title>
</head>
<body>
<form th:action="@{/employee}" method="post"><input type="hidden" name="_method" value="put"><input type="hidden" name="id" th:value="${employee.id}" >lastName:<input type="text" name="lastName" th:value="${employee.lastName}"><br>email:<input type="text" name="email" th:value="${employee.email}"><br>gender:<input type="radio" name="gender" value="1" th:field="${employee.gender}">男<input type="radio" name="gender" value="0" th:field="${employee.gender}">女<br><input type="submit" value="修改">
</form>
</body>
</html>

运行界面

首页

查看所有信息

‘

添加页面

修改界面

二、HttpMessageConverter

请求报文：浏览器到服务器。

响应报文：服务器到浏览器。

1.@RequestBody

将请求报文的请求体转换成java对象。要用post方法。

HttpController中：

package com.pon.controller;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;@Controller
public class HttpController {@RequestMapping("/")public String first(){return "index";}@RequestMapping("/testRequestBody")public String test(@RequestBody String requestBody){System.out.println("requestBoody"+requestBody);return "success";}
}

首页index.html：

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head><meta charset="UTF-8"><title>Title</title>
</head>
<body>
<h1>首页</h1>
<form th:action="@{/testRequestBody}" method="post"><input type="text" name="username"><br><input type="password" name="password"><br><input type="submit" value="测试@RequestBody">
</form>
</body>
</html>

成功后的页面success.html：

<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>Title</title>
</head>
<body>
成功
</body>
</html>

运行界面

2.RequestEntity

HttpController中：

@Controller
public class HttpController {@RequestMapping("/testRequestEntity")public String test1(RequestEntity<String> requestEntity){//requestEntity请求报文的整个信息System.out.println("请求头："+requestEntity.getHeaders());System.out.println("请求体"+requestEntity.getBody());return "success";}
}

首页index.html:

<form th:action="@{/testRequestEntity}" method="post"><input type="text" name="username"><br><input type="password" name="password"><br><input type="submit" value="测试RequestEntity">
</form>

3.@ResponseBody

方法返回值return ".."（双引号里），是什么浏览器界面显示什么。例如 retrun "你好" 浏览器界面显示你好。

4.@ResponseBody处理json对象

创建一个User实体类对象：

package com.pon.bean;public class User {private String username;private Integer age;private String sex;public User() {}public User(String username, Integer age, String sex) {this.username = username;this.age = age;this.sex = sex;}public String getUsername() {return username;}public void setUsername(String username) {this.username = username;}public Integer getAge() {return age;}public void setAge(Integer age) {this.age = age;}public String getSex() {return sex;}public void setSex(String sex) {this.sex = sex;}
}

HttpController:

@Controller
public class HttpController {
@RequestMapping("/testResponseUser")
@ResponseBodypublic User test2(){return new User("adimin",21,"男");
}
}

首页index.html：

<a th:href="@{/testResponseUser}">测试ResponseUser</a>

5.@RestController

6.ResponseEntity

1）文件下载

用ResponseEntity实现文件的下载功能。

在webapp创建static目录，在static目录下创建img，里面复制一张图片

在controller包下，FileDown类：

package com.pon.controller;import jakarta.servlet.ServletContext;
import jakarta.servlet.http.HttpSession;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.util.MultiValueMap;
import org.springframework.web.bind.annotation.RequestMapping;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;@Controller
public class FileDown {@RequestMapping("/file")public String testfile(){return "file";}@RequestMapping("/testDown")public ResponseEntity<byte[]> test(HttpSession httpSession) throws IOException {//获取serveletcontext对象ServletContext servletContext=httpSession.getServletContext();//获取服务器中文件的真实路径String realPath=servletContext.getRealPath("/static/img/001.png");//创建输入流InputStream is=new FileInputStream(realPath);//创建字节流byte[] bytes=new byte[is.available()];is.read(bytes);//创建HttpHeaders对象设置响应头信息MultiValueMap<String,String> headers=new HttpHeaders();//设置下载方式及下载文件的名字headers.add("Content-Disposition","attachment;filename=001.png");//设置响应状态码HttpStatus status=HttpStatus.OK;//创建responseEntity对象ResponseEntity<byte []> responseEntity=new ResponseEntity<>(bytes,headers,status);is.close();return responseEntity;}
}

file.html：

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head><meta charset="UTF-8"><title>Title</title>
</head>
<body>
<a th:href="@{/testDown}">图片下载</a>
</body>
</html>

2)文件上传

文件上传用的是post。

先在pom.xml中添加所需要的依赖：

要将spring-webmvc的版本配置为5.3.19,如果使用6.0.X的话,在spring.xml中配置文件上传解析器配置不了。

 <dependency><groupId>commons-fileupload</groupId><artifactId>commons-fileupload</artifactId><version>1.3.1</version></dependency>

在spring.xml中配置文件上传解析器

<bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"></bean>

在fileUp类中：

package com.pon.controller;import jakarta.servlet.ServletContext;
import jakarta.servlet.http.HttpSession;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.multipart.MultipartFile;
import java.io.File;
import java.io.IOException;@Controller
public class FileUp {@RequestMapping("/testUp")public String testup(MultipartFile photo, HttpSession session) throws IOException {String fileName=photo.getOriginalFilename();ServletContext context=session.getServletContext();String photoPath=context.getRealPath("photo");File file=new File(photoPath);//判断phoroPath路径是否存在if(!file.exists()){//不存在创建file.mkdir();}String finalPath=photoPath+File.separator+fileName;photo.transferTo(new File(finalPath));return "success";}
}

testUp.html中：

<!DOCTYPE html>
<html lang="en" xmlns:th="http://www.thymeleaf.org">
<head><meta charset="UTF-8"><title>Title</title>
</head>
<body>
<a th:href="@{/testDown}">图片下载</a>
<form th:action="@{/testUp}" method="post" enctype="multipart/form-data">头像：<input type="file" name="photo"><br><input type="submit" value="上传">
</form>
</body>
</html>

在target中：

三、拦截器

拦截器作用于controller前后，过滤器作用于请求到DispatcherServlet之间。

拦截器类FirstInterceptor :

package com.pon.interceptor;import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;public class FirstInterceptor implements HandlerInterceptor {//控制器方法执行前执行@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {System.out.println("拦截器preHandle方法执行");return true;}//控制器方法执行后执行@Overridepublic void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {System.out.println("拦截器postHandle方法执行");}//渲染视图完毕后执行@Overridepublic void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {System.out.println("拦截器afterCompletion方法执行");}
}

配置拦截器：在spring.xml中进行配置

第一种方法：

对所有请求都进行拦截

 <!--配置拦截器--><mvc:interceptors><bean class="com.pon.interceptor.FirstInterceptor"/></mvc:interceptors>

第二种方法：

要在拦截器类上配置@Component注解

也是对所有请求都进行拦截。

 <mvc:interceptors><ref bean="firstInterceptor"></ref></mvc:interceptors>

第三种方法：

可设置当前的拦截路径

 <!--配置拦截器--><mvc:interceptors><mvc:interceptor><mvc:mapping path="/*"/><mvc:exclude-mapping path="/"/><ref bean="firstInterceptor"></ref></mvc:interceptor></mvc:interceptors>