27 KiB
27 KiB
springmvc基础（基于注解）
目录
一、搭建hello spring工程
1.1 项目搭建
1.2 相关注解说明
二、配置自定义拦截器
三、全局异常处理
四、参数绑定
4.1 参数绑定
4.2 关于日期格式转换的三种方法
五、数据校验
六、文件上传与下载
6.1 文件上传
6.2 文件下载
七、Restful风格的请求
正文
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.得益于servlet3.0和spring的支持，我们可以在没有web.xml的情况下完成关于servlet配置。
新建DispatcherServletInitializer.java文件,这个类的作用相当于我们在xml方式下web.xml中配置的DispatcherServlet
package com.heibaiying.config;
import org.springframework.web.servlet.support.AbstractAnnotationConfigDispatcherServletInitializer;
/**
* @author : heibaiying
*/
public class DispatcherServletInitializer extends AbstractAnnotationConfigDispatcherServletInitializer {
protected Class<?>[] getRootConfigClasses() {
return new Class[0];
}
protected Class<?>[] getServletConfigClasses() {
return new Class[]{ServletConfig.class};
}
protected String[] getServletMappings() {
return new String[]{"/"};
}
}
3.新建ServletConfig.java，文件内容如下(这个类相当于我们在xml配置方式中的springApplication.xml)
package com.heibaiying.config;
import com.heibaiying.exception.NoAuthExceptionResolver;
import com.heibaiying.interceptors.MyFirstInterceptor;
import com.heibaiying.interceptors.MySecondInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.HandlerExceptionResolver;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.DefaultServletHandlerConfigurer;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import java.util.List;
/**
* @author : heibaiying
*/
@Configuration
@EnableWebMvc
@ComponentScan(basePackages = {"com.heibaiying.controller"})
public class ServletConfig implements WebMvcConfigurer {
/**
* 配置视图解析器
*/
@Bean
public ViewResolver viewResolver() {
InternalResourceViewResolver internalResourceViewResolver = new InternalResourceViewResolver();
internalResourceViewResolver.setPrefix("/WEB-INF/jsp/");
internalResourceViewResolver.setSuffix(".jsp");
internalResourceViewResolver.setExposeContextBeansAsAttributes(true);
return internalResourceViewResolver;
}
/**
* 配置静态资源处理器
*/
public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
configurer.enable();
}
}
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 相关注解说明
1.@Configuration
@Configuration用于定义配置类，可替换xml配置文件，被注解的类内部包含有一个或多个被@Bean注解的方法，这些方法将会被AnnotationConfigApplicationContext或AnnotationConfigWebApplicationContext类进行扫描，并用于构建bean定义，初始化Spring容器。
2.@EnableWebMvc
简单的说就是提供了部分springmvc的功能，例如格式转换和参数绑定。
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ServletConfig.java中注册自定义拦截器
/**
* 添加自定义拦截器
*/
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(new MyFirstInterceptor()).addPathPatterns("/mvc/**").excludePathPatterns("mvc/login");
registry.addInterceptor(new MySecondInterceptor()).addPathPatterns("/mvc/**");
}
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ServletConfig.java注册自定义异常处理器
/**
* 添加全局异常处理器
*/
public void configureHandlerExceptionResolvers(List<HandlerExceptionResolver> resolvers) {
resolvers.add(new 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ServletConfig.java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;
}
}
ServletConfig.java
/**
* 添加全局日期处理
*/
public void addFormatters(FormatterRegistry registry) {
registry.addConverter(new CustomDateConverter());
}
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ServletConfig.java中进行配置，使之支持文件上传
/**
* 配置文件上传
*/
@Bean
public CommonsMultipartResolver multipartResolver(){
CommonsMultipartResolver resolver = new CommonsMultipartResolver();
resolver.setMaxUploadSize(1024*1000*10);
resolver.setMaxUploadSizePerFile(1024*1000);
resolver.setDefaultEncoding("utf-8");
return resolver;
}
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());
}
}