Servlet3.0新特性WebFilter（Annotation Filter）详解
摘要：
Servlet3.0作为J2EE 6规范一部分，并随J2EE6一起发布，WeFilter是过滤器注解，是Servlet3.0的新特性，不需要在web.xml进行配置，简化了配置。
|
Name |
Type |
Required |
Description |
|
filterName |
String |
Optional |
Name of the filter. |
|
value or urlPatterns |
String[] |
Required |
Specify one or more URL patterns to which the filter applies. Either of attribute can be used, but not both. |
|
dispatcherTypes |
DispatcherType[] |
Optional |
Specify types of dispatcher to which the filter applies. Default isjavax.servlet.DispatcherType.REQUEST |
|
servletNames |
String[] |
Optional |
Specify names of servlets to which the filter applies. |
|
displayName |
String |
Optional |
Display name of the filter. |
|
description |
String |
Optional |
Description of the filter. |
|
asyncSupported |
boolean |
Optional |
Specify whether the filter supports asynchronous operation mode. Default is false. |
|
initParams |
WebInitParam[] |
Optional |
Specify one or more initialization parameters of the filter. Each parameter is specified by@WebInitParamannotation type. |
|
smallIcon |
String |
Optional |
Specify name of the small icon of the filter. |
|
largeIcon |
String |
Optional |
Specify name of the large icon of the filter. |
OneFilter：
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package com.what21.servlet.webfilter;import java.io.IOException;import javax.servlet.Filter;import javax.servlet.FilterChain;import javax.servlet.FilterConfig;import javax.servlet.ServletException;import javax.servlet.ServletRequest;import javax.servlet.ServletResponse;import javax.servlet.annotation.WebFilter;@WebFilter("/*")public class OneFilter implements Filter { @Override public void init(FilterConfig config) throws ServletException { } @Override public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { System.out.println("OneFilter doFilter()"); chain.doFilter(request, response); } @Override public void destroy() { }} |
TwoFilter：
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package com.what21.servlet.webfilter;import java.io.IOException;import javax.servlet.Filter;import javax.servlet.FilterChain;import javax.servlet.FilterConfig;import javax.servlet.ServletException;import javax.servlet.ServletRequest;import javax.servlet.ServletResponse;import javax.servlet.annotation.WebFilter;@WebFilter(servletNames = "MyFourServlet")public class TwoFilter implements Filter { @Override public void init(FilterConfig config) throws ServletException { } @Override public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { System.out.println("TwoFilter doFilter()"); chain.doFilter(request, response); } @Override public void destroy() { }} |
ThreeFilter：
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package com.what21.servlet.webfilter;import java.io.IOException;import javax.servlet.Filter;import javax.servlet.FilterChain;import javax.servlet.FilterConfig;import javax.servlet.ServletException;import javax.servlet.ServletRequest;import javax.servlet.ServletResponse;import javax.servlet.annotation.WebFilter;@WebFilter(servletNames = {"MyFourServlet", "MyFiveServlet"})public class ThreeFilter implements Filter { @Override public void init(FilterConfig config) throws ServletException { } @Override public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { System.out.println("ThreeFilter doFilter()"); chain.doFilter(request, response); } @Override public void destroy() { }} |
FourFilter：
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package com.what21.servlet.webfilter;import java.io.IOException;import javax.servlet.Filter;import javax.servlet.FilterChain;import javax.servlet.FilterConfig;import javax.servlet.ServletException;import javax.servlet.ServletRequest;import javax.servlet.ServletResponse;import javax.servlet.annotation.WebFilter;@WebFilter({"/one","/two"})public class FourFilter implements Filter { @Override public void init(FilterConfig config) throws ServletException { } @Override public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { System.out.println("FourFilter doFilter()"); chain.doFilter(request, response); } @Override public void destroy() { }} |
FiveFilter：
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package com.what21.servlet.webfilter;import java.io.IOException;import javax.servlet.DispatcherType;import javax.servlet.Filter;import javax.servlet.FilterChain;import javax.servlet.FilterConfig;import javax.servlet.ServletException;import javax.servlet.ServletRequest;import javax.servlet.ServletResponse;import javax.servlet.annotation.WebFilter;import javax.servlet.annotation.WebInitParam;@WebFilter( urlPatterns = "/five", filterName = "FiveFilter", initParams = { @WebInitParam(name = "name", value = "username"), @WebInitParam(name = "value", value = "password") }, description = "MyFiveFilter", dispatcherTypes = {DispatcherType.REQUEST, DispatcherType.FORWARD})public class FiveFilter implements Filter { @Override public void init(FilterConfig config) throws ServletException { String name = config.getInitParameter("name"); String value = config.getInitParameter("value"); System.out.println("name = " + name); System.out.println("value = " + value); System.out.println("init()....."); } @Override public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException { System.out.println("FiveFilter doFilter()"); } @Override public void destroy() { }} |
