下面我将为您详细讲解“SpringMVC高级开发功能实现过程解析”这个主题的完整攻略。
一、SpringMVC高级开发功能实现的准备工作
在进行SpringMVC高级开发功能的实现之前,首先需要对SpringMVC基础知识掌握熟练,包括控制器的编写、配置、映射、请求参数的获取、转发和重定向等。另外,还需要掌握Spring的Bean管理、AOP、事务处理等相关知识。
二、SpringMVC高级开发功能实现过程
1. 异常处理
异常处理是系统进行效率调优和避免系统崩溃的重要手段。在SpringMVC中,异常处理主要是通过异常映射完成的。具体步骤如下:
- 编写自己的异常类
- 编写异常处理器
- 配置异常处理器和异常映射
示例:假设我们需要在SpringMVC中实现NullPointerException异常的处理。
- 编写自己的异常类:
public class MyException extends Exception{
public MyException(String message) {
super(message);
}
}
- 编写异常处理器:
@ControllerAdvice
public class MyExceptionHandler {
@ExceptionHandler(NullPointerException.class)
public ModelAndView handleRuntimeException(HttpServletRequest request,MyException ex){
ModelAndView modelAndView = new ModelAndView();
modelAndView.addObject("exception", ex);
modelAndView.addObject("url", request.getRequestURL());
modelAndView.setViewName("error");
return modelAndView;
}
}
- 最后在配置文件中配置异常处理器和异常映射即可。配置方式如下:
<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
<property name="argumentResolvers">
<list>
<bean class="org.springframework.web.method.support.HandlerMethodArgumentResolverComposite">
<property name="resolvers">
<list>
<bean class="org.springframework.web.method.support.MapMethodProcessor" />
<bean class="org.springframework.web.servlet.mvc.method.annotation.PathVariableMethodArgumentResolver" />
</list>
</property>
</bean>
</list>
</property>
<property name="messageConverters">
<list>
<bean class="org.springframework.http.converter.StringHttpMessageConverter" />
<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter" />
</list>
</property>
<property name="exceptionResolvers">
<list>
<bean class="org.springframework.web.servlet.mvc.method.annotation.ExceptionHandlerExceptionResolver" />
<bean class="org.springframework.web.servlet.mvc.method.annotation.ResponseStatusExceptionResolver"/>
<bean class="org.springframework.web.servlet.mvc.support.DefaultHandlerExceptionResolver"/>
</list>
</property>
</bean>
2. 文件上传
文件上传在Web开发中经常会用到。SpringMVC中通过MultipartFile实现文件上传。具体步骤如下:
- 编写一个文件上传表单,在表单中加入 enctype="multipart/form-data"
- 编写Controller,接收文件上传的请求,并将文件上传到服务器指定目录
示例:假设我们需要在SpringMVC中实现文件上传功能。
- 编写文件上传表单:
<form method="POST" action="/upload" enctype="multipart/form-data">
<input type="file" name="file"/>
<input type="submit" value="上传"/>
</form>
- 编写Controller,实现文件上传的请求处理:
@Controller
public class UploadController{
@RequestMapping(value = "/upload", method = RequestMethod.POST)
public String handleFileUpload(@RequestParam("file") MultipartFile file,
RedirectAttributes redirectAttributes) {
if (!file.isEmpty()) {
try {
byte[] bytes = file.getBytes();
BufferedOutputStream bufferedOutputStream =
new BufferedOutputStream(new FileOutputStream(new File("D:/test/" + file.getOriginalFilename())));
bufferedOutputStream.write(bytes);
bufferedOutputStream.close();
redirectAttributes.addFlashAttribute("message",
"You successfully uploaded " + file.getOriginalFilename() + "!");
} catch (IOException e) {
e.printStackTrace();
}
} else {
redirectAttributes.addFlashAttribute("message",
"You failed to upload " + file.getOriginalFilename() + " because the file was empty.");
}
return "redirect:/";
}
}
3. WebSocket实时通信
WebSocket是HTML5中新的协议,可以实现客户端和服务器之间的实时通信。SpringMVC中通过WebSocketHandler实现实时通信。具体步骤如下:
- 编写WebSocketHandler。WebSocketHandler接口中定义了多个方法,其中onOpen()方法用来处理连接请求,onMessage()方法用来处理客户端向服务端发送消息请求,onClose()方法用来处理断开请求,onError()方法用来处理异常请求。
- 配置WebSocketHandler
- 编写前端WebSocket代码
示例:假设我们需要在SpringMVC中实现WebSocket实时通信。
- 编写WebSocketHandler:
@Component
public class MyHandler extends TextWebSocketHandler {
private static final Logger logger = LoggerFactory.getLogger(MyHandler.class);
@Override
protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
logger.info("来自客户端的消息: " + message.getPayload());
TextMessage returnMessage = new TextMessage(message.getPayload());
session.sendMessage(returnMessage);
}
@Override
public void afterConnectionEstablished(WebSocketSession session) throws Exception {
logger.info("WebSocket连接建立成功......");
}
@Override
public void afterConnectionClosed(WebSocketSession session, CloseStatus status) throws Exception {
logger.info("WebSocket连接已关闭!");
}
@Override
public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {
logger.info("WebSocket连接发生错误...");
}
}
- 配置WebSocketHandler:
<mvc:annotation-driven />
<bean class="org.springframework.web.socket.server.standard.ServerEndpointExporter" />
<bean id="myHandler" class="com.test.controller.MyHandler"> </bean>
<bean
class="org.springframework.web.socket.handler.WebSocketHandlerDecoratorFactory">
<constructor-arg>
<bean class="org.springframework.web.socket.server.HandshakeFailureException"></bean>
</constructor-arg>
</bean>
<bean class="org.springframework.web.socket.config.annotation.DelegatingWebSocketMessageBrokerConfiguration">
<property name="clientInboundChannel">
<bean class="org.springframework.messaging.simp.rabbit.RabbitTemplate">
<property name="messagingTemplate">
<bean class="org.springframework.messaging.core.MessagingTemplate">
<constructor-arg ref="clientInboundChannelExecutor" />
</bean>
</property>
<property name="receiveTimeout" value="${spring.messaging.template.receive-timeout:0}" />
<property name="replyTimeout" value="${spring.messaging.template.reply-timeout:0}" />
<property name="messagingConverter" ref="messageConverter"/>
<property name="routingKey" value="${spring.messaging.template.receive-timeout:0}" />
<property name="exchange" value="${spring.messaging.template.reply-timeout:0}" />
<property name="retryTemplate" ref="retryTemplate" />
</bean>
</property>
<property name="clientOutboundChannel">
<bean class="org.springframework.messaging.simp.rabbit.RabbitTemplate">
<property name="messagingTemplate">
<bean class="org.springframework.messaging.core.MessagingTemplate">
<constructor-arg ref="clientOutboundChannelExecutor" />
</bean>
</property>
<property name="receiveTimeout" value="${spring.messaging.template.receive-timeout:0}" />
<property name="replyTimeout" value="${spring.messaging.template.reply-timeout:0}" />
<property name="messagingConverter" ref="messageConverter"/>
<property name="routingKey" value="${spring.messaging.template.receive-timeout:0}" />
<property name="exchange" value="${spring.messaging.template.reply-timeout:0}" />
</bean>
</property>
<property name="messageConverter" ref="messageConverter" />
<property name="destinationPrefixes">
<list>
<value>${spring.websocket.BROKER_PREFIX:/app}</value>
</list>
</property>
<property name="applicationContext" ref="org.springframework.context.annotation.AnnotationConfigApplicationContext#1" />
</bean>
- 编写前端WebSocket代码:
var socket;
if (!window.WebSocket) {
window.WebSocket = window.MozWebSocket;
}
if (window.WebSocket) {
// 连接WebSocket服务器
socket = new WebSocket("ws://localhost:8080/websocket");
// 打开WebSocket连接时,调用onopen函数
socket.onopen = function (event) {
console.log("连接被打开...");
};
// 当服务器向客户端发送消息时,调用onmessage函数
socket.onmessage = function (event) {
console.log("接收到消息: " + event.data);
};
// 关闭WebSocket连接时,调用onclose函数
socket.onclose = function (event) {
console.log("连接被关闭...");
};
} else {
console.log("您的浏览器不支持WebSocket协议...");
}
三、总结
通过以上两个示例,我们可以发现,SpringMVC高级开发功能的实现过程中,需要我们对SpringMVC的基础知识、Bean管理、AOP、事务处理等相关知识有一定的掌握,并能够熟练掌握各种技术的配置和使用。希望通过这篇攻略,能够让大家有一个更深入的了解和体验。
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