239 lines
7.6 KiB
Markdown
239 lines
7.6 KiB
Markdown
# Spring Boot 整合 Servlet
|
||
|
||
|
||
<nav>
|
||
<a href="#一项目说明">一、项目说明</a><br/>
|
||
<a href="#11-结构说明">1.1 结构说明</a><br/>
|
||
<a href="#12-项目依赖">1.2 项目依赖</a><br/>
|
||
<a href="#二Spring-注册方式">二、Spring 注册方式</a><br/>
|
||
<a href="#21-组件声明">2.1 组件声明</a><br/>
|
||
<a href="#22-组件注册">2.2 组件注册</a><br/>
|
||
<a href="#三原生注解方式">三、原生注解方式</a><br/>
|
||
<a href="#31-组件声明">3.1 组件声明</a><br/>
|
||
<a href="#32-组件生效">3.2 组件生效</a><br/>
|
||
</nav>
|
||
|
||
## 一、项目说明
|
||
|
||
### 1.1 结构说明
|
||
|
||
- 项目提供与 Servlet 整合的两种方式，一种是 Servlet 3.0 原生的注解方式，一种是采用 Spring 注册的方式；
|
||
- Servlet、过滤器、监听器分别位于 servlet、filter、listen 下，其中以 Annotation 命名结尾的代表是 Servlet 是以注解方式实现，采用 Spring 注册方式则需要在 ServletConfig 中进行注册；
|
||
- 为了说明外置容器对 Servlet 注解的自动发现机制，项目采用外置容器构建，关于 Spring Boot 整合外置容器的详细说明可以参考：[spring-boot-tomcat](https://github.com/heibaiying/spring-samples-for-all/tree/master/spring-boot/spring-boot-tomcat) 。
|
||
|
||
<div align="center"> <img src="https://github.com/heibaiying/spring-samples-for-all/blob/master/pictures/spring-boot-servlet.png"/> </div>
|
||
|
||
### 1.2 项目依赖
|
||
|
||
```xml
|
||
<dependencies>
|
||
<dependency>
|
||
<groupId>org.springframework.boot</groupId>
|
||
<artifactId>spring-boot-starter-web</artifactId>
|
||
<!--排除依赖 使用外部 tomcat 容器启动-->
|
||
<exclusions>
|
||
<exclusion>
|
||
<groupId>org.springframework.boot</groupId>
|
||
<artifactId>spring-boot-starter-tomcat</artifactId>
|
||
</exclusion>
|
||
</exclusions>
|
||
</dependency>
|
||
<dependency>
|
||
<!--使用外置容器时候 SpringBootServletInitializer 依赖此包 -->
|
||
<groupId>javax.servlet</groupId>
|
||
<artifactId>servlet-api</artifactId>
|
||
<version>2.5</version>
|
||
<scope>provided</scope>
|
||
</dependency>
|
||
<!--servlet api 注解依赖包-->
|
||
<dependency>
|
||
<groupId>javax.servlet</groupId>
|
||
<artifactId>javax.servlet-api</artifactId>
|
||
</dependency>
|
||
</dependencies>
|
||
```
|
||
|
||
## 二、Spring 注册方式
|
||
|
||
### 2.1 组件声明
|
||
|
||
声明过滤器、监听器和 Servlet：
|
||
|
||
```java
|
||
/**
|
||
* @description : 自定义过滤器
|
||
*/
|
||
public class CustomFilter implements Filter {
|
||
|
||
@Override
|
||
public void init(FilterConfig filterConfig) throws ServletException {
|
||
|
||
}
|
||
|
||
@Override
|
||
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
|
||
request.setAttribute("filterParam","我是 filter 传递的参数");
|
||
chain.doFilter(request,response);
|
||
response.getWriter().append(" CustomFilter ");
|
||
}
|
||
|
||
@Override
|
||
public void destroy() {
|
||
|
||
}
|
||
}
|
||
```
|
||
|
||
```java
|
||
/**
|
||
* @description : 自定义监听器
|
||
*/
|
||
public class CustomListen implements ServletContextListener {
|
||
|
||
//Web 应用程序初始化过程正在启动的通知
|
||
@Override
|
||
public void contextInitialized(ServletContextEvent sce) {
|
||
System.out.println("容器初始化启动");
|
||
}
|
||
|
||
|
||
|
||
/* 通知 servlet 上下文即将关闭
|
||
* 这个地方如果我们使用的是 spring boot 内置的容器 是监听不到销毁过程，所以我们使用了外置 tomcat 容器
|
||
*/
|
||
@Override
|
||
public void contextDestroyed(ServletContextEvent sce) {
|
||
System.out.println("容器即将销毁");
|
||
}
|
||
}
|
||
```
|
||
|
||
```java
|
||
/**
|
||
* @description : 自定义 servlet
|
||
*/
|
||
public class CustomServlet extends HttpServlet {
|
||
|
||
@Override
|
||
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
|
||
System.out.println("doGet 执行：" + req.getAttribute("filterParam"));
|
||
resp.getWriter().append("CustomServlet");
|
||
}
|
||
|
||
@Override
|
||
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
|
||
doGet(req, resp);
|
||
}
|
||
}
|
||
```
|
||
|
||
### 2.2 组件注册
|
||
|
||
```java
|
||
@Configuration
|
||
public class ServletConfig {
|
||
|
||
@Bean
|
||
public ServletRegistrationBean registrationBean() {
|
||
return new ServletRegistrationBean<HttpServlet>(new CustomServlet(), "/servlet");
|
||
}
|
||
|
||
@Bean
|
||
public FilterRegistrationBean filterRegistrationBean() {
|
||
FilterRegistrationBean bean = new FilterRegistrationBean<Filter>();
|
||
bean.setFilter(new CustomFilter());
|
||
bean.addUrlPatterns("/servlet");
|
||
return bean;
|
||
}
|
||
|
||
@Bean
|
||
public ServletListenerRegistrationBean listenerRegistrationBean() {
|
||
return new ServletListenerRegistrationBean<ServletContextListener>(new CustomListen());
|
||
}
|
||
|
||
}
|
||
```
|
||
|
||
## 三、原生注解方式
|
||
|
||
### 3.1 组件声明
|
||
|
||
新建过滤器、监听器和 servlet,分别使用 @WebFilter、@WebListener、@WebServlet 注解进行声明：
|
||
|
||
```java
|
||
/**
|
||
* @description : 自定义过滤器
|
||
*/
|
||
|
||
@WebFilter(urlPatterns = "/servletAnn")
|
||
public class CustomFilterAnnotation implements Filter {
|
||
|
||
@Override
|
||
public void init(FilterConfig filterConfig) throws ServletException {
|
||
|
||
}
|
||
|
||
@Override
|
||
public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
|
||
chain.doFilter(request,response);
|
||
response.getWriter().append(" CustomFilter Annotation");
|
||
}
|
||
|
||
@Override
|
||
public void destroy() {
|
||
|
||
}
|
||
}
|
||
```
|
||
|
||
```java
|
||
/**
|
||
* @description :自定义监听器
|
||
*/
|
||
@WebListener
|
||
public class CustomListenAnnotation implements ServletContextListener {
|
||
|
||
//Web 应用程序初始化过程正在启动的通知
|
||
@Override
|
||
public void contextInitialized(ServletContextEvent sce) {
|
||
System.out.println("容器初始化启动 Annotation");
|
||
}
|
||
|
||
|
||
|
||
/* 通知 servlet 上下文即将关闭
|
||
* 这个地方如果我们使用的是 spring boot 内置的容器 是监听不到销毁过程，所以我们使用了外置 tomcat 容器
|
||
*/
|
||
@Override
|
||
public void contextDestroyed(ServletContextEvent sce) {
|
||
System.out.println("容器即将销毁 Annotation");
|
||
}
|
||
}
|
||
```
|
||
|
||
```java
|
||
/**
|
||
* @description : 自定义 servlet
|
||
*/
|
||
@WebServlet(urlPatterns = "/servletAnn")
|
||
public class CustomServletAnnotation extends HttpServlet {
|
||
|
||
@Override
|
||
protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
|
||
resp.getWriter().append("CustomServlet Annotation");
|
||
}
|
||
|
||
@Override
|
||
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
|
||
doGet(req, resp);
|
||
}
|
||
}
|
||
```
|
||
|
||
### 3.2 组件生效
|
||
|
||
想要让使用 Servlet 3.0 原生注解方式声明的组件生效，有以下两种方式：
|
||
|
||
- 如果是内置容器，需要在启动类上添加 @ServletComponentScan ，指定扫描的包目录；
|
||
- 如果是外置容器，不需要进行任何配置，依靠容器内建的 Discovery 机制自动发现，需要说明的是这里的容器必须支持 Servlet 3.0（ Tomcat 从 7.0 版本开始支持 Servlet3.0）。
|