spring 5.x 系列第1篇 —— springmvc基础 (xml配置方式)

时间:2023-03-10 04:42:51
spring 5.x 系列第1篇 —— springmvc基础 (xml配置方式)

源码Gitub地址:https://github.com/heibaiying/spring-samples-for-all

一、搭建hello spring工程

1.1 项目搭建

1.新建maven web工程,并引入相应的依赖

 <properties>
        <spring-base-version>5.1.3.RELEASE</spring-base-version>
 </properties>

<dependencies>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring-base-version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>${spring-base-version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring-base-version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-web</artifactId>
            <version>${spring-base-version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>${spring-base-version}</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>4.0.1</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>

2.配置web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee
		 http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
         version="3.1">

    <!--配置spring前端控制器-->
    <servlet>
        <servlet-name>springMvc</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath:springApplication.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>springMvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

</web-app>

3.在resources下新建springApplication.xml文件,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: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-4.1.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.1.xsd">

    <!-- 开启注解包扫描-->
    <context:component-scan base-package="com.heibaiying.*"/>

    <!--使用默认的Servlet来响应静态文件 详见 1.2 -->
    <mvc:default-servlet-handler/>

    <!-- 开启注解驱动 详见 1.2 -->
    <mvc:annotation-driven/>

    <!-- 配置视图解析器 -->
    <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"
          id="internalResourceViewResolver">
        <!-- 前缀 -->
        <property name="prefix" value="/WEB-INF/jsp/"/>
        <!-- 后缀 -->
        <property name="suffix" value=".jsp"/>
    </bean>

</beans>

4.在src 下新建controller用于测试

package com.heibaiying.controller;

import com.heibaiying.exception.NoAuthException;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;

/**
 * @author : heibaiying
 * @description : hello spring
 */

@Controller
@RequestMapping("mvc")
public class HelloController {

    @RequestMapping("hello")
    private String hello() {
        return "hello";
    }

}

5.在WEB-INF 下新建jsp文件夹,新建hello.jsp 文件

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
    Hello Spring MVC!
</body>
</html>

6.启动tomcat服务,访问localhost:8080/mvc/hello

1.2 相关配置讲解

1.<mvc:default-servlet-handler/>

在web.xml配置中,我们将DispatcherServlet的拦截路径设置为“\”,则spring会捕获所有web请求,包括对静态资源的请求,为了正确处理对静态资源的请求,spring提供了两种解决方案:

  • 配置<mvc:default-servlet-handler/> : 配置<mvc:default-servlet-handler />后,会在Spring MVC上下文中定义一个org.springframework.web.servlet.resource.DefaultServletHttpRequestHandler,它会对进入DispatcherServlet的URL进行筛查,如果发现是静态资源的请求,就将该请求转由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。

  • 配置<mvc:resources /> :指定静态资源的位置和路径映射:

    <mvc:resources location="/img/" mapping="/img/**"/>
    <mvc:resources location="/js/" mapping="/js/**"/>
    <mvc:resources location="/css/" mapping="/css/**"/>
    

2.<mvc:annotation-driven/>

<mvc:annotation-driven /> 会自动注册DefaultAnnotationHandlerMapping与AnnotationMethodHandlerAdapter
两个bean,用以支持@Controllers分发请求。并提供了数据绑定、参数转换、json转换等功能,所以必须加上这个配置。

二、配置自定义拦截器

1.创建自定义拦截器,实现接口HandlerInterceptor(这里我们创建两个拦截器,用于测试拦截器方法的执行顺序)

package com.heibaiying.interceptors;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * @author : heibaiying
 * @description : spring5 中 preHandle,postHandle,afterCompletion 在接口中被声明为默认方法
 */
public class MyFirstInterceptor implements HandlerInterceptor {

    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
        System.out.println("进入第一个拦截器preHandle");
        return true;
    }

    // 需要注意的是,如果对应的程序报错,不一定会进入这个方法 但一定会进入afterCompletion这个方法
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) {
        System.out.println("进入第一个拦截器postHandle");
    }

    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {
        System.out.println("进入第一个拦截器afterCompletion");
    }
}
package com.heibaiying.interceptors;

import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * @author : heibaiying
 * @description : spring5 中 preHandle,postHandle,afterCompletion 在接口中被声明为默认方法
 */
public class MySecondInterceptor implements HandlerInterceptor {

    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) {
        System.out.println("进入第二个拦截器preHandle");
        return true;
    }

    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) {
        System.out.println("进入第二个拦截器postHandle");
    }

    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {
        System.out.println("进入第二个拦截器afterCompletion");
    }
}

2.在springApplication.xml中注册自定义拦截器

    <!--配置拦截器-->
    <mvc:interceptors>
        <mvc:interceptor>
            <mvc:mapping path="/mvc/**"/>
            <mvc:exclude-mapping path="/mvc/login"/>
            <bean class="com.heibaiying.interceptors.MyFirstInterceptor"/>
        </mvc:interceptor>
        <mvc:interceptor>
            <mvc:mapping path="/mvc/**"/>
            <bean class="com.heibaiying.interceptors.MySecondInterceptor"/>
        </mvc:interceptor>
    </mvc:interceptors>

3.关于多个拦截器方法执行顺序的说明

拦截器的执行顺序是按声明的先后顺序执行的,先声明的拦截器中的preHandle方法会先执行,然而它的postHandle方法和afterCompletion方法却会后执行。

三、全局异常处理

1.定义自定义异常

package com.heibaiying.exception;

/**
 * @author : heibaiying
 * @description : 自定义无权限异常
 */
public class NoAuthException extends RuntimeException {

    public NoAuthException() {
        super();
    }

    public NoAuthException(String message) {
        super(message);
    }

    public NoAuthException(String message, Throwable cause) {
        super(message, cause);
    }

    public NoAuthException(Throwable cause) {
        super(cause);
    }

}

2.实现自定义异常处理器

package com.heibaiying.exception;

import org.springframework.web.servlet.HandlerExceptionResolver;
import org.springframework.web.servlet.ModelAndView;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * @author : heibaiying
 * @description : 无权限异常处理机制
 */
public class NoAuthExceptionResolver implements HandlerExceptionResolver {

    public ModelAndView resolveException(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {
        if (ex instanceof NoAuthException && !isAjax(request)) {
            return new ModelAndView("NoAuthPage");
        }
        return new ModelAndView();
    }

    // 判断是否是Ajax请求
    private boolean isAjax(HttpServletRequest request) {
        return "XMLHttpRequest".equalsIgnoreCase(request.getHeader("X-Requested-With"));
    }
}

3.在springApplication.xml注册自定义异常处理器

<!--配置全局异常处理器-->
<bean class="com.heibaiying.exception.NoAuthExceptionResolver"/>

4.定义测试controller,抛出自定义异常

@Controller
@RequestMapping("mvc")
public class HelloController {

    @RequestMapping("hello")
    private String hello() {
        return "hello";
    }

    @RequestMapping("auth")
    private void auth() {
        throw new NoAuthException("没有对应的访问权限!");
    }
}

注:调用这个controller时,同时也可以验证在拦截器部分提到的:如果对应的程序报错,拦截器不一定会进入postHandle这个方法 但一定会进入afterCompletion这个方法

四、参数绑定

4.1 参数绑定

1.新建Programmer.java

package com.heibaiying.bean;

import lombok.Data;

/**
 * @author : heibaiying
 * @description :
 */
@Data
public class Programmer {

    private String name;

    private int age;

    private float salary;

    private String birthday;
}

注:@Data 是lombok包下的注解,用来生成相应的set、get方法,使得类的书写更为简洁。

2.新建ParamBindController.java 文件

package com.heibaiying.controller;

import com.heibaiying.bean.Programmer;
import org.springframework.format.annotation.DateTimeFormat;
import org.springframework.format.datetime.DateFormatter;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.WebDataBinder;
import org.springframework.web.bind.annotation.InitBinder;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;

import java.util.Date;

/**
 * @author : heibaiying
 * @description :参数绑定
 */
@Controller
public class ParamBindController {

    @InitBinder
    protected void initBinder(WebDataBinder binder) {
        binder.addCustomFormatter(new DateFormatter("yyyy-MM-dd HH:mm:ss"));
    }

    // 参数绑定与日期格式转换
    @RequestMapping("param")
    public String param(String name, int age, double salary, @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss") Date birthday, Model model) {
        model.addAttribute("name", name);
        model.addAttribute("age", age);
        model.addAttribute("salary", salary);
        model.addAttribute("birthday", birthday);
        return "param";
    }

    @RequestMapping("param2")
    public String param2(String name, int age, double salary, Date birthday, Model model) {
        model.addAttribute("name", name);
        model.addAttribute("age", age);
        model.addAttribute("salary", salary);
        model.addAttribute("birthday", birthday);
        return "param";
    }

    @PostMapping("param3")
    public String param3(Programmer programmer, String extendParam, Model model) {
        System.out.println("extendParam" + extendParam);
        model.addAttribute("p", programmer);
        return "param";
    }

}

3.新建param.jsp 文件

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Restful</title>
</head>
<body>
<ul>
    <li>姓名:${empty name ? p.name : name}</li>
    <li>年龄:${empty age ? p.age : age}</li>
    <li>薪酬:${empty salary ? p.salary : salary}</li>
    <li>生日:${empty birthday ? p.birthday : birthday}</li>
</ul>
</body>
</html>

4.启动tomcat,用postman软件发送请求进行测试

4.2 关于日期格式转换的三种方法

1.如上实例代码所示,在对应的controller中初始化绑定

@InitBinder
    protected void initBinder(WebDataBinder binder) {
        binder.addCustomFormatter(new DateFormatter("yyyy-MM-dd HH:mm:ss"));
    }

2.利用@DateTimeFormat注解,如果是用实体类去接收参数,则在对应的属性上用@DateTimeFormat和@JsonFormat声明

public String param(@DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss") Date birthday)

3.使用全局的日期格式绑定,新建自定义日期格式转化类,之后在springApplication.xml中进行注册

package com.heibaiying.convert;

import org.springframework.core.convert.converter.Converter;

import java.text.SimpleDateFormat;
import java.util.Date;

/**
 * @author : heibaiying
 * @description :
 */
public class CustomDateConverter implements Converter<String, Date> {

    public Date convert(String s) {
        try {
            SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
            return simpleDateFormat.parse(s);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
}

springApplication.xml

<!-- 全局日期格式转换  -->
    <bean id="formattingConversionService" class="org.springframework.format.support.FormattingConversionServiceFactoryBean">
    <property name="converters">
        <list>
            <bean class="com.heibaiying.convert.CustomDateConverter"/>
        </list>
    </property>
    </bean>

五、数据校验

1.spring支持的数据校验是JSR303的标准,需要引入依赖的jar包

 <!-- 数据校验依赖包 -->
      <dependency>
            <groupId>org.hibernate.validator</groupId>
            <artifactId>hibernate-validator</artifactId>
            <version>6.0.13.Final</version>
        </dependency>
        <dependency>
            <groupId>javax.validation</groupId>
            <artifactId>validation-api</artifactId>
            <version>2.0.1.Final</version>
        </dependency>

2.新建测试ParamValidController.java,主要是在需要校验的参数前加上@Validated,声明参数需要被校验,同时加上bindingResult参数,这个参数中包含了校验的结果

package com.heibaiying.controller;

import com.heibaiying.bean.Programmer;
import org.hibernate.validator.constraints.Length;
import org.springframework.format.annotation.DateTimeFormat;
import org.springframework.format.datetime.DateFormatter;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.validation.BindingResult;
import org.springframework.validation.ObjectError;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.WebDataBinder;
import org.springframework.web.bind.annotation.InitBinder;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.validation.constraints.Min;
import javax.validation.constraints.NotNull;
import java.util.Date;
import java.util.List;

/**
 * @author : heibaiying
 * @description :数据校验
 */
@RestController
public class ParamValidController {

    @PostMapping("validate")
    public void valid(@Validated Programmer programmer,
                      BindingResult bindingResult) {
        List<ObjectError> allErrors = bindingResult.getAllErrors();
        for (ObjectError error : allErrors) {
            System.out.println(error.getDefaultMessage());
        }
    }

}

3.在Programmer.java的对应属性上加上注解约束(支持的注解可以在javax.validation.constraints包中查看)

package com.heibaiying.bean;

import lombok.Data;

import javax.validation.constraints.Min;
import javax.validation.constraints.NotNull;

/**
 * @author : heibaiying
 * @description :
 */
@Data
public class Programmer {

    @NotNull
    private String name;

    @Min(value = 0,message = "年龄不能为负数!" )
    private int age;

    @Min(value = 0,message = "薪酬不能为负数!" )
    private float salary;

    private String birthday;
}

六、文件上传与下载

6.1 文件上传

1.在springApplication.xml中进行配置,使之支持文件上传

 <!--配置文件上传-->
    <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
         <!--文件最大限制-->
        <property name="maxUploadSize" value="102400000"/>
          <!--单个文件最大限制-->
        <property name="maxUploadSizePerFile" value="10240000"/>
        <property name="defaultEncoding" value="utf-8"/>
    </bean>

2.新建测试上传的FileController.java

package com.heibaiying.controller;

import com.heibaiying.utils.FileUtil;
import org.apache.commons.io.FileUtils;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.HttpSession;
import java.io.File;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;

/**
 * @author : heibaiying
 * @description : 文件上传
 */

@Controller
public class FileController {

    @GetMapping("file")
    public String filePage() {
        return "file";
    }

    /***
     * 单文件上传
     */
    @PostMapping("upFile")
    public String upFile(MultipartFile file, HttpSession session) {
        //保存在项目根目录下image文件夹下,如果文件夹不存在则创建
        FileUtil.saveFile(file, session.getServletContext().getRealPath("/image"));
        // success.jsp 就是一个简单的成功页面
        return "success";
    }

    /***
     * 多文件上传 多个文件用同一个名字
     */
    @PostMapping("upFiles")
    public String upFiles(@RequestParam(name = "file") MultipartFile[] files, HttpSession session) {
        for (MultipartFile file : files) {
            FileUtil.saveFile(file, session.getServletContext().getRealPath("images"));
        }
        return "success";
    }

    /***
     * 多文件上传方式2 分别为不同文件指定不同名字
     */
    @PostMapping("upFiles2")
    public String upFile(String extendParam,
                         @RequestParam(name = "file1") MultipartFile file1,
                         @RequestParam(name = "file2") MultipartFile file2, HttpSession session) {
        String realPath = session.getServletContext().getRealPath("images2");
        FileUtil.saveFile(file1, realPath);
        FileUtil.saveFile(file2, realPath);
        System.out.println("extendParam:" + extendParam);
        return "success";
    }
}

3.其中工具类FileUtil.java代码如下

package com.heibaiying.utils;

import org.springframework.web.multipart.MultipartFile;
import java.io.*;

/**
 * @author : heibaiying
 * @description : 文件上传工具类
 */

public class FileUtil {

    public static String saveFile(MultipartFile file, String path) {
        InputStream inputStream = null;
        FileOutputStream outputStream = null;
        String fullPath = path + File.separator + file.getOriginalFilename();
        try {
            File saveDir = new File(path);
            if (!saveDir.exists()) {
                saveDir.mkdirs();
            }
            outputStream = new FileOutputStream(new File(fullPath));
            inputStream = file.getInputStream();
            byte[] bytes = new byte[1024 * 1024];
            int read;
            while ((read = inputStream.read(bytes)) != -1) {
                outputStream.write(bytes, 0, read);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (inputStream != null) {
                try {
                    inputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (outputStream != null) {
                try {
                    outputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return fullPath;
    }

}

4.新建用于上传的jsp页面,上传文件时表单必须声明 enctype=“multipart/form-data”

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>文件上传</title>
    <link rel="stylesheet" href="${pageContext.request.contextPath}/css/file.css">
</head>
<body>

    <form action="${pageContext.request.contextPath }/upFile" method="post" enctype="multipart/form-data">
        请选择上传文件:<input name="file" type="file"><br>
        <input type="submit" value="点击上传文件">
    </form>

    <form action="${pageContext.request.contextPath }/upFiles" method="post" enctype="multipart/form-data">
        请选择上传文件(多选):<input name="file" type="file" multiple><br>
        <input type="submit" value="点击上传文件">
    </form>

    <form action="${pageContext.request.contextPath }/upFiles2" method="post" enctype="multipart/form-data">
        请选择上传文件1:<input name="file1" type="file"><br>
        请选择上传文件2:<input name="file2" type="file"><br>
        文件内容额外备注: <input name="extendParam" type="text"><br>
        <input type="submit" value="点击上传文件">
    </form>

</body>
</html>

6.2 文件下载

1.在fileController.java中加上方法:

  /***
   * 上传用于下载的文件
   */
    @PostMapping("upFileForDownload")
    public String upFileForDownload(MultipartFile file, HttpSession session, Model model) throws UnsupportedEncodingException {
        String path = FileUtil.saveFile(file, session.getServletContext().getRealPath("/image"));
        model.addAttribute("filePath", URLEncoder.encode(path,"utf-8"));
        model.addAttribute("fileName", file.getOriginalFilename());
        return "fileDownload";
    }

    /***
     * 下载文件
     */
    @GetMapping("download")
    public ResponseEntity<byte[]> downloadFile(String filePath) throws IOException {
        HttpHeaders headers = new HttpHeaders();
        File file = new File(filePath);
        // 解决文件名中文乱码
        String fileName=new String(file.getName().getBytes("UTF-8"),"iso-8859-1");
        headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
        headers.setContentDispositionFormData("attachment", fileName);

        return new ResponseEntity<byte[]>(FileUtils.readFileToByteArray(file),
                headers, HttpStatus.CREATED);
    }

2.其中fileDownload.jsp 如下:

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>文件下载</title>
</head>
<body>
    <a href="${pageContext.request.contextPath}/download?filePath=${filePath}">${fileName}</a>
</body>
</html>

七、Restful风格的请求

1.新建Pet.java实体类

package com.heibaiying.bean;

import lombok.Data;

/**
 * @author : heibaiying
 * @description :测试restful风格的实体类
 */

@Data
public class Pet {

    private String ownerId;

    private String petId;
}

2.新建RestfulController.java,用@PathVariable和@ModelAttribute注解进行参数绑定。

注: 在REST中,资源通过URL进行识别和定位。REST中的行为是通过HTTP方法定义的。在进行不同行为时对应HTTP方法和Spring注解分别如下:

  • 创建资源时:POST(PostMapping)
  • 读取资源时:GET( @GetMapping)
  • 更新资源时:PUT或PATCH(PutMapping、PatchMapping)
  • 删除资源时:DELETE(DeleteMapping)
package com.heibaiying.controller;

import com.heibaiying.bean.Pet;
import org.springframework.validation.annotation.Validated;
import org.springframework.web.bind.annotation.*;

/**
 * @author : heibaiying
 * @description : Restful 风格的请求
 */

@RestController
public class RestfulController {

    @GetMapping("restful/owners/{ownerId}/pets/{petId}")
    public void get(@PathVariable String ownerId, @PathVariable String petId) {
        System.out.println("ownerId:" + ownerId);
        System.out.println("petId:" + petId);
    }

    @GetMapping("restful2/owners/{ownerId}/pets/{petId}")
    public void get(@ModelAttribute Pet pet) {
        System.out.println("ownerId:" + pet.getOwnerId());
        System.out.println("petId:" + pet.getPetId());
    }

}

附:源码Gitub地址:https://github.com/heibaiying/spring-samples-for-all