Spring集成Web环境 1.配置ContextLoaderListener监听器
1 2 3 4 5 6 7 8 9 <context-param > <param-name > contextConfigLocation</param-name > <param-value > classpath:applicationContext.xml</param-value > </context-param > <listener > <listener-class > org.springframework.web.context.ContextLoaderListener</listener-class > </listener >
2.使用WebApplicationContextUtils获得应用上下文
SpringMVC F:\java_code\heima_SpringMVC
SpringMVC开发步骤
需求:客户端发起请求，服务器端接受请求，执行逻辑并进行试图跳转。
1.导入SpringMVC相关坐标
2.配置SpringMVC核心控制器DispatcherServlet（⭐）
web.xml
1 2 3 4 5 6 7 8 9 10 11 12 13 <servlet > <servlet-name > DispatcherServlet</servlet-name > <servlet-class > org.springframework.web.servlet.DispatcherServlet</servlet-class > <init-param > <param-name > contextConfigLocation</param-name > <param-value > classpath:spring-mvc.xml</param-value > </init-param > <load-on-startup > 1</load-on-startup > </servlet > <servlet-mapping > <servlet-name > DispatcherServlet</servlet-name > <url-pattern > /</url-pattern > </servlet-mapping >
3.创建Controller类和视图界面
4.使用注解配置Controller类中业务方法的映射地址
5.配置SpringMVC核心文件spring-mvc.xml
6.客户端发起请求测试
1.用户发送请求至前端控制器DispatcherServlet。
2.DispatcherServlet收到请求调用HandlerMapping处理器映射器。
3.处理器映射器找到具体的处理器(可以根据xml配置、注解进行查找)，生成处理器对象及处理器拦截器(如果
有则生成)一并返回给DispatcherServlet.
4.DispatcherServlet调用HandlerAdapter处理器适配器。
5.HandlerAdapter经过适配调用具体的处理器(Controller，也叫后端控制器)。
6.Controller执行完成返回ModelAndView。
7.HandlerAdapter将controller执行结果ModelAndView返回给DispatcherServlet.
8.DispatcherServlet将ModelAndView传给ViewReslover视图解析器。
9.ViewReslover解析后返回具体View。
10.DispatcherServlet根据View进行渲染视图(即将模型数据填充至视图中)。DispatcherServlet响应用户。
xml试图解析器 1 2 3 4 5 6 <bean id ="viewResolver" class ="org.springframework.web.servlet.view.InternalResourceViewResolver" > <property name ="prefix" value ="/jsp/" /> <property name ="suffix" value =".jsp" /> </bean >
重定向前缀：redirect:
转发前缀(默认值)：forward:
SpringMVC的数据响应方式 1）页面跳转 直接返回字符串
同上
Controller 层 部分代码
1 2 3 4 5 @RequestMapping(value = "/quick",method = RequestMethod.GET) public String save () System.out.println("UserController.save" ); return "success" ; }
通过ModelAndView对象返回
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 @RequestMapping(value = "/quick2") public ModelAndView save2 () ModelAndView modelAndView = new ModelAndView(); modelAndView.addObject("username" ,"itcast" ); modelAndView.setViewName("success" ); return modelAndView; } @RequestMapping(value = "/quick3") public ModelAndView save3 (ModelAndView modelAndView) modelAndView.addObject("username" ,"itheima" ); modelAndView.setViewName("success" ); return modelAndView; } @RequestMapping(value = "/quick4") public String save4 (Model model) model.addAttribute("username" ,"save4" ); return "success" ; } @RequestMapping(value = "/quick5") public String save5 (HttpServletRequest request) request.setAttribute("username" ,"save5" ); return "success" ; }
2）回写数据 直接返回字符串
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 @RequestMapping(value = "/quick6") public void save6 (HttpServletResponse response) throws IOException response.getWriter().println("hello itcast" ); } @RequestMapping(value = "/quick7") @ResponseBody public String save7 () throws IOException return "hello save7" ; } @RequestMapping(value = "/quick8") @ResponseBody public String save8 () throws IOException return "{\"username\":\"zhangsan\",\"age\":18}" ; } @RequestMapping(value = "/quick9") @ResponseBody public String save9 () throws IOException User user = new User(); user.setName("lili" ); user.setAge(30 ); ObjectMapper objectMapper = new ObjectMapper(); String json = objectMapper.writeValueAsString(user); return json; }
返回对象和集合
pom.xml
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 <dependency > <groupId > com.fasterxml.jackson.core</groupId > <artifactId > jackson-core</artifactId > <version > 2.9.8</version > </dependency > <dependency > <groupId > com.fasterxml.jackson.core</groupId > <artifactId > jackson-databind</artifactId > <version > 2.9.8</version > </dependency > <dependency > <groupId > com.fasterxml.jackson.core</groupId > <artifactId > jackson-annotations</artifactId > <version > 2.9.8</version > </dependency >
Controller
1 2 3 4 5 6 7 8 9 @RequestMapping(value = "/quick10") @ResponseBody public User save10 () throws IOException User user = new User(); user.setName("lili" ); user.setAge(30 ); return user; }
spring-mvc.xml
1 2 3 4 5 6 7 8 9 10 11 12 <mvc:annotation-driven />
SpringMVC获得请求参数 基本类型参数 Controller中的业务方法的参数名称与请求参数的name一致，参数值会自动映射匹配
1 2 3 4 5 6 @RequestMapping(value = "/quick11") @ResponseBody public void save11 (String username,Integer age) throws IOException System.out.println("username = " + username); System.out.println("age = " + age); }
POJO类型参数(简单JavaBean) Controller中的业务方法的POJO参数与请求参数的name一致，参数值会自动映射匹配
1 2 3 4 5 @RequestMapping(value = "/quick12") @ResponseBody public void save12 (User user) throws IOException System.out.println("user = " + user); }
数组类型参数 Controller中的业务方法的数组名称与请求参数的name一致，参数值会自动映射匹配
1 2 3 4 5 @RequestMapping(value = "/quick13") @ResponseBody public void save13 (String[] strings) throws IOException System.out.println("Arrays.asList(strings) = " + Arrays.asList(strings)); }
集合类型参数（1）
Controller
1 2 3 4 5 @RequestMapping(value = "/quick14") @ResponseBody public void save14 (VO vo) throws IOException System.out.println("vo = " + vo); }
VO.java
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 public class VO private List<User> userList; public List<User> getUserList () return userList; } public void setUserList (List<User> userList) this .userList = userList; } @Override public String toString () final StringBuffer sb = new StringBuffer("VO{" ); sb.append("userList=" ).append(userList); sb.append('}' ); return sb.toString(); } }
集合类型参数（2） 当使用ajax提交时，可以指定contentType为json形式，那么在方法参数位置使用@RequestBody可以直接接收集合数据而无需使用POJO进行包装。
ajax.jsp
1 2 3 4 5 6 7 8 9 10 11 12 13 14 <script src="${pageContext.request.contextPath}/js/jquery-3.3.1.js" ></script> <script> var userList = new Array(); userList.push({username:"zhangsan" ,age:18 }); userList.push({username:"lisi" ,age:28 }); $.ajax({ type:"POST" , url:"${pageContext.request.contextPath}/user/quick15" , data:JSON.stringify(userList), contentType:"application/json;charset=utf-8" }); </script>
Controller
1 2 3 4 5 @RequestMapping(value = "/quick15") @ResponseBody public void save15 (@RequestBody List<User> userList) throws IOException System.out.println("userList = " + userList); }
spring-mvc.xml
1 <mvc:resources mapping ="/js/**" location ="/js/" />
静态资源访问的开启（⭐） 1 2 3 4 5 <mvc:default-servlet-handler />
请求数据乱码问题 web.xml
1 2 3 4 5 6 7 8 9 10 11 12 13 <filter > <filter-name > CharacterEncodingFilter</filter-name > <filter-class > org.springframework.web.filter.CharacterEncodingFilter</filter-class > <init-param > <param-name > encoding</param-name > <param-value > utf-8</param-value > </init-param > </filter > <filter-mapping > <filter-name > CharacterEncodingFilter</filter-name > <url-pattern > /*</url-pattern > </filter-mapping >
参数绑定注解@RequestParam 当请求的参数名称与Controller的业务方法参数名称不一致时，就需要通过@RequestParam注解显式的绑定
1 2 3 4 5 6 7 8 9 10 11 12 @RequestMapping(value = "/quick16") @ResponseBody public void save16 (@RequestParam(value = "name") String username) throws IOException System.out.println("username = " + username); } @RequestMapping(value = "/quick17/{username}") @ResponseBody public void save17 (@PathVariable(value = "username") String username) throws IOException System.out.println("username = " + username); }
获取Restful风格的参数 Restful是一种软件架构风格、设计风格，而不是标准，只是提供了一组设计原则和约束条件。主要用于客户端和服务器交互类的软件，基于这个风格设计的软件可以更简洁，更有层次，更易于实现缓存机制等。
Restful风格的请求是使用“url+请求方式”表示一次请求目的的，HTTP协议里面四个表示操作方式的动词如下:
GET:用于获取资源
POST:用于新建资源
PUT:用于更新资源
DELETE:用于删除资源
自定义类型转换器 SpringMVC默认已经提供了一些常用的类型转换器，例客户端提交的字符串转换成int型进行参数设置。
但不是所有的数据类型都提供了转换器，没有提供的就需要自定义转换器，例如:日期类型的数据就需要自定义转换器。
自定义类型转换器的开发步骤:
定义转换器类实现Converter接口
在配置文件中声明转换器
在< annotation-driven >中引用转换器
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 import org.springframework.core.convert.converter.Converter;public class DateConverter implements Converter <String , Date > @Override public Date convert (String datestr) SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd" ); Date parse = null ; try { parse = format.parse(datestr); } catch (ParseException e) { e.printStackTrace(); } return parse; } }
spring-mvc.xml
1 2 3 4 5 6 7 8 9 10 11 <bean id ="ConversionService" class ="org.springframework.context.support.ConversionServiceFactoryBean" > <property name ="converters" > <list > <bean class ="converter.DateConverter" /> </list > </property > </bean > <mvc:annotation-driven conversion-service ="ConversionService" />
获得请求头 @RequestHeader
使用@RequestHeader可以获得请求头信息，相当于web阶段学习的request.getHeader(name)
@RequestHeader注解的属性如下:
@CookieValue
文件上传 1.三要素
表单项type = “file”
表单的提交方式post
表单的enctype属性是多部分表单形式，及enctype= “multipart/form-data”
1 2 3 4 5 6 <form action="${pageContext.request.contextPath}/user/quick22" method="post" enctype="multipart/form-data" > 名称<input type="text" name="username" ><br/> 文件<input type="file" name="upload" ><br/> <input type="submit" value="提交" > </form>
2.文件上传原理
单文件上传步骤 1.导入fileupload和io坐标
1 2 3 4 5 6 7 8 9 10 <dependency > <groupId > commons-fileupload</groupId > <artifactId > commons-fileupload</artifactId > <version > 1.3.3</version > </dependency > <dependency > <groupId > commons-io</groupId > <artifactId > commons-io</artifactId > <version > 2.6</version > </dependency >
2.配置文件上传解析器
1 2 3 4 5 <bean id ="multipartResolver" class ="org.springframework.web.multipart.commons.CommonsMultipartResolver" > <property name ="defaultEncoding" value ="utf-8" /> <property name ="maxUploadSize" value ="5242800" /> </bean >
3.编写文件上传代码
1 2 3 4 5 6 7 8 @RequestMapping(value = "/quick22") @ResponseBody public void save22 (String username, MultipartFile upload) throws IOException System.out.println("username = " + username); String filename = upload.getOriginalFilename(); upload.transferTo(new File("F:\\java_code\\" +filename)); }
多文件上传 1 2 3 4 5 6 7 8 9 10 11 @RequestMapping(value = "/quick22") @ResponseBody public void save22 (String username, MultipartFile upload,MultipartFile upload2) throws IOException System.out.println("username = " + username); String filename = upload.getOriginalFilename(); upload.transferTo(new File("F:\\java_code\\" +filename)); String filename2 = upload2.getOriginalFilename(); upload.transferTo(new File("F:\\java_code\\" +filename2)); }
也可for循环 —–>MultipartFile[] upload
SpringMVC拦截器 F:\java_code\heima_SpringMVC_interceptor
拦截器（interceptor）的作用
SpringMVC类似于Servlet开发中的过滤器Filter，用于对处理器进行预处理和后处理。
将拦截器按一定的顺序联结成一条链，这条链称为拦截器链(Interceptor Chain)。在访问被拦截的方法或字段时，拦截器链中的拦截器就会按其之前定义的顺序被调用。拦截器也是AOP思想的具体实现。
步骤
1.创建拦截器类实现HandlerInterceptor接口
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 public class MyInterceptor1 implements HandlerInterceptor @Override public boolean preHandle (HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception System.out.println("MyInterceptor1.preHandle" ); return true ; } @Override public void postHandle (HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception System.out.println("MyInterceptor1.postHandle" ); } @Override public void afterCompletion (HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception System.out.println("MyInterceptor1.afterCompletion" ); } }
2.配置拦截器
1 2 3 4 5 6 7 8 <mvc:interceptors > <mvc:interceptor > <mvc:mapping path ="/**" /> <bean class ="interceptor.MyInterceptor1" /> </mvc:interceptor > </mvc:interceptors >
3.测试拦截器的拦截结果
拦截器方法说明
SpringMVC异常处理 方法1.使用SpringMVC提供的简单异常处理器SimpleMappingExceptionResolver
方法2.实现Spring的异常处理接口HandlerExceptionResolver自定义自己的异常处理器
1.创建异常处理器实现HandlerExceptionResolver接口
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 public class MyExceptionResolver implements HandlerExceptionResolver @Override public ModelAndView resolveException (HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) ModelAndView modelAndView = new ModelAndView(); if (e instanceof MyException){ modelAndView.addObject("info" ,"自定义异常" ); } else if (e instanceof ClassCastException){ modelAndView.addObject("info" ,"类转换异常" ); } modelAndView.setViewName("error" ); return modelAndView; } }
2.配置异常处理器
1 2 <bean class ="resolver.MyExceptionResolver" />
3.编写异常页面
