本文主要是介绍四十九、SpingBoot引入第三方filter,希望对大家解决编程问题提供一定的参考价值,需要的开发者们随着小编来一起学习吧!
最近手头活不多,被其他项目拉去帮忙。他们的需求是,项目中需要加入第三方的过滤器(用于单点登录认证的),项目采用的是spring boot,spring boot之前没深入玩过,所以费了些时间。
需求:
第三方提供了一个filter以及使用标准web.xml时的配置方法,要求整合到项目中
过程:
第一步:
作为不百度(google)不会写代码的程序员,第一反应是去baidu一下,毕竟spring boot的使用停留在写web api的码砖水平上。百度结果,大部分都是用类似下面的方法:
@Beanpublic FilterRegistrationBean pluginFilter(){//将第三方filter实例,配置信息设置到一个FilterRegistrationBean中//详细代码省略,网上到处都是}
优点在于:简单。
缺点:这种第三方的filter,如果是多个的,每个都得重新加这种方法,对于扩展来说,啰嗦
于是,寻求spring boot项目直接使用web.xml里过滤器配置的方案,百度了好些,都是直接将spring boot项目变为使用web.xml配置的,这个动作有点大,怕把项目给搞乱了,没敢采用。。。
第二步:
目标明确为,使用Bean标签返回FilterRegistrationBean(或类似的接口实例)的方向,但是这个Bean要能将多个过滤器注册给spring。稍微读了一下源码,发现FilterRegistrationBean这个鬼,这正起作用的是定义在AbstractFilterRegistrationBean中的方法onStartup方法
public void onStartup(ServletContext servletContext) throws ServletException {Filter filter = this.getFilter();Assert.notNull(filter, "Filter must not be null");String name = this.getOrDeduceName(filter);if (!this.isEnabled()) {this.logger.info("Filter " + name + " was not registered (disabled)");} else { Dynamic added = servletContext.addFilter(name, filter);if (added == null) {this.logger.info("Filter " + name + " was not registered (possibly already registered?)");} else {this.configure(added);}} }
所以,咱们重写一下这个onStartup方法(类名后缀用的proxy可能不太合适,请不要在意细节):
package com.xxx.common.filter;import org.dom4j.Document; import org.dom4j.Element; import org.springframework.boot.web.servlet.FilterRegistrationBean;import javax.servlet.Filter; import javax.servlet.ServletContext; import javax.servlet.ServletException; import java.util.HashMap; import java.util.Iterator; import java.util.Map;public class XxxFilterRegistrationBeanProxy extends FilterRegistrationBean{private Document plugin_xml = null;//所有需要注册的filterprivate Map<String,FilterRegistrationBean> filterRegistrationBeans;public IdssFilterRegistrationBeanProxy() {}public Document getPlugin_xml() {return plugin_xml;}public void setPlugin_xml(Document plugin_xml) {this.plugin_xml = plugin_xml;}public IdssFilterRegistrationBeanProxy(Document plugin_xml) throws IllegalAccessException, InstantiationException, ClassNotFoundException {super();this.plugin_xml = plugin_xml;setFilterRegistrationBeans();}@Overridepublic void onStartup(ServletContext servletContext) throws ServletException {if(filterRegistrationBeans == null || filterRegistrationBeans.size()==0) return;//执行实际的FilterRegistrationBean的onStartup方法for(FilterRegistrationBean bean : filterRegistrationBeans.values()){bean.onStartup(servletContext);}}private void setFilterRegistrationBeans() throws ClassNotFoundException, IllegalAccessException, InstantiationException {//读取xml配置文件,实例化FilterRegistrationBeanif(plugin_xml == null) return;filterRegistrationBeans = new HashMap<>();Element root = plugin_xml.getRootElement();Iterator<Element> filter_roots = root.elementIterator("filter");int order = 0;while (filter_roots.hasNext()){order++;Element filter_root = filter_roots.next();String filter_name = filter_root.elementText("filter-name").trim();String class_name = filter_root.elementText("filter-class").trim();Filter filter = (Filter) Class.forName(class_name).newInstance();FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean();filterRegistrationBean.setFilter(filter);filterRegistrationBean.setName(filter_name);filterRegistrationBean.setOrder(order);Iterator<Element> parm_settings = filter_root.elementIterator("init-param");while (parm_settings.hasNext()){Element parm = parm_settings.next();filterRegistrationBean.addInitParameter(parm.elementText("param-name").trim(),parm.elementText("param-value").trim());}filterRegistrationBeans.put(filter_name,filterRegistrationBean);}Iterator<Element> filter_mappings = root.elementIterator("filter-mapping");while (filter_mappings.hasNext()){Element filter_mapping = filter_mappings.next();String filter_name = filter_mapping.elementText("filter-name");if(filterRegistrationBeans.containsKey(filter_name)){filterRegistrationBeans.get(filter_name).addUrlPatterns(filter_mapping.elementText("url-pattern"));}}} }
注入spring boot的单例类中,给出一个Bean注解的方法,返回上面类的实例
package com.xxx.common.filter;import com.xxx.common.utils.PropertyUtil; import org.dom4j.Document; import org.dom4j.DocumentException; import org.dom4j.io.SAXReader; import org.springframework.boot.web.servlet.FilterRegistrationBean; import org.springframework.context.annotation.Bean; import org.springframework.stereotype.Component;import javax.annotation.PostConstruct; import java.io.IOException; import java.io.InputStreamReader;@Component public class XxxPluginFilter {private XxxFilterRegistrationBeanProxy XxxFilterRegistrationBeanProxy = new XxxFilterRegistrationBeanProxy();private Document plugin_xml = null;private final static String plugin_filter_path = PropertyUtil.getProperty("plugin_filter_path");@Beanpublic FilterRegistrationBean pluginFilter(){return XxxFilterRegistrationBeanProxy;}@PostConstructprivate void init() throws IllegalAccessException, InstantiationException, ClassNotFoundException {if(plugin_filter_path == null || plugin_filter_path.isEmpty()) return;SAXReader reader = new SAXReader();InputStreamReader inputStreamReader = null;try {inputStreamReader = new InputStreamReader(this.getClass().getClassLoader().getResourceAsStream(plugin_filter_path));plugin_xml = reader.read(inputStreamReader);xxxFilterRegistrationBeanProxy = new XxxFilterRegistrationBeanProxy(plugin_xml);} catch (DocumentException e) {e.printStackTrace();} finally {if(inputStreamReader != null) {try {inputStreamReader.close();} catch (IOException e) {e.printStackTrace();}}}} }
filter的xml配置文件示例:
<?xml version="1.0" encoding="UTF-8"?> <plugin-filter><filter><filter-name>filter1</filter-name><filter-class>com.test.Filter1</filter-class><init-param><param-name>servername</param-name><param-value>http://localhost:8081</param-value></init-param></filter><filter><filter-name>filter2</filter-name><filter-class>com.test.Filter2</filter-class><init-param><param-name>initteset</param-name><param-value>yyyy</param-value></init-param></filter><filter-mapping><!-- 需要过滤的路径和文件类型 --><filter-name>filter1</filter-name><url-pattern>/*</url-pattern></filter-mapping><filter-mapping><filter-name>filter2</filter-name><url-pattern>/api/*</url-pattern></filter-mapping> </plugin-filter>
简单粗暴而有效
这篇关于四十九、SpingBoot引入第三方filter的文章就介绍到这儿,希望我们推荐的文章对编程师们有所帮助!