一、说明
Web 开发使用 Controller 基本上可以完成大部分需求，但是我们还可能会用到 Servlet、 Filter、Listener 等等
二、在spring boot中的三种实现方式
2.1、代码
CustomServlet.java:
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package
com.example.demo.utils.servlet;
import
javax.servlet.ServletException;
import
javax.servlet.http.HttpServlet;
import
javax.servlet.http.HttpServletRequest;
import
javax.servlet.http.HttpServletResponse;
import
java.io.IOException;
/**
* 自定义 servlet
*
*/
public
class
CustomServlet
extends
HttpServlet {
private
static
final
long
serialVersionUID = 1L;
@Override
protected
void
doGet(HttpServletRequest request, HttpServletResponse response)
throws
ServletException, IOException {
System.out.println(
"servlet get method"
);
doPost(request, response);
}
@Override
protected
void
doPost(HttpServletRequest request, HttpServletResponse response)
throws
ServletException, IOException {
System.out.println(
"servlet post method"
);
response.getWriter().write(
"hello world"
);
}
}
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CustomFilter.java：
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package
com.example.demo.utils.filter;
import
javax.servlet.*;
import
java.io.IOException;
/**
* 自定义 filter
* Created by DELL on 2017/6/17.
*/
public
class
CustomFilter
implements
Filter {
@Override
public
void
init(FilterConfig filterConfig)
throws
ServletException {
System.out.println(
"init filter"
);
}
@Override
public
void
doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
throws
IOException, ServletException {
System.out.println(
"do filter"
);
chain.doFilter(request, response);
}
@Override
public
void
destroy() {
System.out.println(
"destroy filter"
);
}
}
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CustomListener.java:
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package
com.example.demo.utils.listener;
import
javax.servlet.ServletContextEvent;
import
javax.servlet.ServletContextListener;
/**
* 自定义 listener
* Created by DELL on 2017/6/17.
*/
public
class
CustomListener
implements
ServletContextListener {
@Override
public
void
contextInitialized(ServletContextEvent sce) {
System.out.println(
"contextInitialized"
);
}
@Override
public
void
contextDestroyed(ServletContextEvent sce) {
System.out.println(
"contextDestroyed"
);
}
}
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2.2、方式一：通过注册ServletRegistrationBean、FilterRegistrationBean和ServletListenerRegistrationBean
2.2.1、注册ServletRegistrationBean
Application中注册bean:
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/**注册CustomServlet*/
@Bean
public
ServletRegistrationBean servletRegistrationBean() {
return
new
ServletRegistrationBean(
new
CustomServlet(),
"/roncoo"
);
}
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2.2.2、注册FilterRegistrationBean
Application中注册bean:
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/**注册CustomFilter*/
@Bean
public
FilterRegistrationBean filterRegistrationBean() {
return
new
FilterRegistrationBean(
new
CustomFilter(), servletRegistrationBean());
}
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2.2.3、注册ServletListenerRegistrationBean
Application中注册bean:
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/**注册CustomListener*/
@Bean
public
ServletListenerRegistrationBean<CustomListener> servletListenerRegistrationBean() {
return
new
ServletListenerRegistrationBean<CustomListener>(
new
CustomListener());
}
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上面所有例子效果：
项目启动：
访问：http://localhost:8080/roncoo
2.3、方式二：通过实现 ServletContextInitializer 接口直接注册
Application实现 ServletContextInitializer 接口：
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package
com.example.demo;
import
com.example.demo.utils.filter.CustomFilter;
import
com.example.demo.utils.listener.CustomListener;
import
com.example.demo.utils.servlet.CustomServlet;
import
org.springframework.boot.SpringApplication;
import
org.springframework.boot.autoconfigure.SpringBootApplication;
import
org.springframework.boot.web.servlet.FilterRegistrationBean;
import
org.springframework.boot.web.servlet.ServletContextInitializer;
import
org.springframework.boot.web.servlet.ServletListenerRegistrationBean;
import
org.springframework.boot.web.servlet.ServletRegistrationBean;
import
org.springframework.context.annotation.Bean;
import
javax.servlet.DispatcherType;
import
javax.servlet.ServletContext;
import
javax.servlet.ServletException;
import
java.util.EnumSet;
@SpringBootApplication
public
class
SpringbootDemo27Application
implements
ServletContextInitializer {
@Override
public
void
onStartup(ServletContext servletContext)
throws
ServletException {
servletContext.addServlet(
"customServlet"
,
new
CustomServlet()).addMapping(
"/roncoo"
);
servletContext.addFilter(
"customFilter"
,
new
CustomFilter()).addMappingForServletNames(EnumSet.of(DispatcherType.REQUEST),
true
,
"customServlet"
);
servletContext.addListener(
new
CustomListener());
}
public
static
void
main(String[] args) {
SpringApplication.run(SpringbootDemo27Application.
class
, args);
}
}
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2.4、方式三：
在SpringBootApplication上使用@ServletComponentScan注解后，直接通过@WebServlet、@WebFilter、@WebListener注解自动注册
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@ServletComponentScan
@SpringBootApplication
public
class
SpringbootDemo27Application {
//...
}
@WebServlet
(urlPatterns =
"/roncoo"
, name =
"customServlet"
)
public
class
CustomServlet
extends
HttpServlet {
//...
}
@WebFilter
(urlPatterns =
"/*"
)
public
class
CustomFilter
implements
Filter {
//...
}
@WebListener
public
class
CustomListener
implements
ServletContextListener {
//...
}
本文转自我爱大金子博客51CTO博客，原文链接http://blog.51cto.com/1754966750/1939406如需转载请自行联系原作者
我爱大金子
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