1.传统的filter的加载方式
filter的组成部分
- filter配置类
- 拦截的路径
- 初始化参数
- 忽略的路径
<filter>
<filter-name>TestFilter</filter-name>
<filter-class>com.cppba.filter.TestFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>TestFilter</filter-name>
<url-pattern>/*</url-pattern>
<init-param>
<param-name>paramName</param-name>
<param-value>paramValue</param-value>
</init-param>
</filter-mapping>
2.SpringBoot加载filter的方式(方法一)
2.1 SpringBoot加载filter的方式(方法一)
- .创建自定义Filter
import javax.servlet.*;
import java.io.IOException;
public class TestFilter implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain)
throws IOException, ServletException {
System.out.println("TestFilter");
}
@Override
public void destroy() {
}
}
- .加载并初始化filter
@Bean
public FilterRegistrationBean testFilterRegistration() {
FilterRegistrationBean registration = new FilterRegistrationBean();
registration.setFilter(new TestFilter());
registration.addUrlPatterns("/*");
registration.addInitParameter("paramName", "paramValue");
registration.setName("testFilter");
registration.setOrder(1);
return registration;
}
2.2.SpringBoot加载filter的方式(方法二)
- .创建自定义Filter
@Order(1)
//重点
@WebFilter(filterName = "testFilter1", urlPatterns = "/*")
public class TestFilterFirst implements Filter {
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain)
throws IOException, ServletException {
System.out.println("TestFilter1");
filterChain.doFilter(servletRequest,servletResponse);
}
@Override
public void destroy() {
}
}
比较核心的代码是自定义类上面加上@WebFilter;
其中@Order注解表示执行过滤顺序,值越小,越先执行
spring-boot的入口处加上如下注解@ServletComponentScan:
3. 配置多个时执行顺序设置
3.1 通过代码配置方式
在spring boot中的FilterRegistrationBean注册过滤器的类中有个order属性,
private int order = Ordered.LOWEST_PRECEDENCE;
细看源码可以知道,这个order的默认值是Integer.MAX_VALUE 也就是int的最大值,
spring boot 会按照order值的大小,从小到大的顺序来依次过滤。
再有一个过滤器的话,可以设置成 registration.setOrder(Integer.MAX_VALUE - 1)
/**
* 配置过滤器
* @return
*/
@Bean
public FilterRegistrationBean someFilterRegistration() {
FilterRegistrationBean registration = new FilterRegistrationBean();
registration.setFilter(sessionFilter());
registration.addUrlPatterns("/*");
registration.addInitParameter("paramName", "paramValue");
registration.setName("sessionFilter");
registration.setOrder(Integer.MAX_VALUE);
return registration;
}
3.2 通过注解的方式设置
/**
* 配置过滤器
* @return
*/
@Bean
@Order(Integer.MAX_VALUE)
public FilterRegistrationBean someFilterRegistration() {
FilterRegistrationBean registration = new FilterRegistrationBean();
registration.setFilter(sessionFilter());
registration.addUrlPatterns("/*");
registration.addInitParameter("paramName", "paramValue");
registration.setName("sessionFilter");
return registration;
}