nacos client中ConfigFilterChainManager的原理和应用
这篇文章主要介绍"nacos client中ConfigFilterChainManager的原理和应用"，在日常操作中，相信很多人在nacos client中ConfigFilterChainManager的原理和应用问题上存在疑惑，小编查阅了各式资料，整理出简单好用的操作方法，希望对大家解答"nacos client中ConfigFilterChainManager的原理和应用"的疑惑有所帮助！接下来，请跟着小编一起来学习吧！
序
本文主要研究一下nacos client的ConfigFilterChainManager
IConfigFilterChain
nacos-1.1.3/api/src/main/java/com/alibaba/nacos/api/config/filter/IConfigFilterChain.java
public interface IConfigFilterChain { /** * Filter aciton * * @param request request * @param response response * @throws NacosException NacosException */ void doFilter(IConfigRequest request, IConfigResponse response) throws NacosException;}IConfigFilterChain接口定义了doFilter方法
ConfigFilterChainManager
nacos-1.1.3/client/src/main/java/com/alibaba/nacos/client/config/filter/impl/ConfigFilterChainManager.java
public class ConfigFilterChainManager implements IConfigFilterChain { private List filters = Lists.newArrayList(); public synchronized ConfigFilterChainManager addFilter(IConfigFilter filter) { // 根据order大小顺序插入 int i = 0; while (i < this.filters.size()) { IConfigFilter currentValue = this.filters.get(i); if (currentValue.getFilterName().equals(filter.getFilterName())) { break; } if (filter.getOrder() >= currentValue.getOrder() && i < this.filters.size()) { i++; } else { this.filters.add(i, filter); break; } } if (i == this.filters.size()) { this.filters.add(i, filter); } return this; } @Override public void doFilter(IConfigRequest request, IConfigResponse response) throws NacosException { new VirtualFilterChain(this.filters).doFilter(request, response); } //......} ConfigFilterChainManager实现了IConfigFilterChain接口，其doFilter方法使用filters创建VirtualFilterChain，然后执行其doFilter方法；它提供了addFilter方法，可以根据filter的order顺序添加到filters中
VirtualFilterChain
nacos-1.1.3/client/src/main/java/com/alibaba/nacos/client/config/filter/impl/ConfigFilterChainManager.java
public class ConfigFilterChainManager implements IConfigFilterChain { //...... private static class VirtualFilterChain implements IConfigFilterChain { private final List additionalFilters; private int currentPosition = 0; public VirtualFilterChain(List additionalFilters) { this.additionalFilters = additionalFilters; } @Override public void doFilter(final IConfigRequest request, final IConfigResponse response) throws NacosException { if (this.currentPosition != this.additionalFilters.size()) { this.currentPosition++; IConfigFilter nextFilter = this.additionalFilters.get(this.currentPosition - 1); nextFilter.doFilter(request, response, this); } } } //......}VirtualFilterChain实现了IConfigFilterChain接口，它维护了一个currentPosition属性，其doFilter方法会在currentPosition不等于additionalFilters.size()时递增currentPosition，然后取出nextFilter把自己作为参数去执行doFilter
IConfigFilter
nacos-1.1.3/api/src/main/java/com/alibaba/nacos/api/config/filter/IConfigFilter.java
public interface IConfigFilter { /** * Init * * @param filterConfig Filter Config */ void init(IFilterConfig filterConfig); /** * do filter * * @param request request * @param response response * @param filterChain filter Chain * @throws NacosException exception */ void doFilter(IConfigRequest request, IConfigResponse response, IConfigFilterChain filterChain) throws NacosException; /** * deploy */ void deploy(); /** * Get order * * @return order number */ int getOrder(); /** * Get filterName * * @return filter name */ String getFilterName();}IConfigFilter接口的doFilter方法的第三个参数为IConfigFilterChain；其实现类执行完自己的处理之后，如果要继续，可以执行filterChain.doFilter来继续交给下面的filter处理
小结
ConfigFilterChainManager实现了IConfigFilterChain接口，其doFilter方法使用filters创建VirtualFilterChain，然后执行其doFilter方法；它提供了addFilter方法，可以根据filter的order顺序添加到filters中
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