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分布式apollo简介
apollo（阿波罗）是携程框架部门研发的开源配置管理中心，能够集中化管理应用不同环境、不同集群的配置，配置修改后能够实时推送到应用端，并且具备规范的权限、流程治理等特性。
本文主要介绍如何使用apollo与springboot实现动态刷新配置，如果之前不了解apollo可以查看如下文档
学习了解一下apollo，再来查看本文
正文
apollo与spring实现动态刷新配置本文主要演示2种刷新，一种基于普通字段刷新、一种基于bean上使用了@configurationproperties刷新
1、普通字段刷新
a、pom.xml配置
<dependency> <groupid>com.ctrip.framework.apollo</groupid> <artifactid>apollo-client</artifactid> <version>1.6.0</version> </dependency>
b、客户端配置appid，apollo meta server
此配置有多种方法，本示例直接在application.yml配置，配置内容如下
app:
id: ${spring.application.name}
apollo:
meta:
bootstrap:
enabled: true
eagerload:
enabled: true
c、项目中启动类上加上@enableapolloconfig注解，形如下
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@springbootapplication
@enableapolloconfig(value = {"application","user.properties","product.properties","order.properties"})
public class apolloapplication {
public static void main(string[] args) {
springapplication.run(apolloapplication.class, args);
}
}
@enableapolloconfig不一定要加在启动类上，加在被spring管理的类上即可
d、在需刷新的字段上配置@value注解，形如
@value("${hello}")
private string hello;
通过以上三步就可以实现普通字段的动态刷新
2.bean使用@configurationproperties动态刷新
bean使用@configurationproperties注解目前还不支持自动刷新，得编写一定的代码实现刷新。目前官方提供2种刷新方案
a、基于refreshscope实现刷新
1、pom.xml要额外引入
<dependency> <groupid>org.springframework.cloud</groupid> <artifactid>spring-cloud-context</artifactid> <version>2.0.3.release</version> </dependency>
2、bean上使用@refreshscope注解
@component
@configurationproperties(prefix = "product")
@data
@allargsconstructor
@noargsconstructor
@builder
@refreshscope
public class product {
private long id;
private string productname;
private bigdecimal price;
}
3、利用refreshscope搭配@apolloconfigchangelistener监听实现bean的动态刷新，其代码实现如下
@apolloconfigchangelistener(value="product.properties",interestedkeyprefixes = {"product."})
private void refresh(configchangeevent changeevent){
refreshscope.refresh("product");
printchangekeyutils.printchange(changeevent);
}
b、基于environmentchangeevent实现刷新
利用spring的事件驱动配合@apolloconfigchangelistener监听实现bean的动态刷新，其代码如下
@component
@slf4j
public class userpropertiesrefresh implements applicationcontextaware {
private applicationcontext applicationcontext;
@apolloconfigchangelistener(value="user.properties",interestedkeyprefixes = {"user."})
private void refresh(configchangeevent changeevent){
applicationcontext.publishevent(new environmentchangeevent(changeevent.changedkeys()));
printchangekeyutils.printchange(changeevent);
}
@override
public void setapplicationcontext(applicationcontext applicationcontext) throws beansexception {
this.applicationcontext = applicationcontext;
}
}
c、当bean上有@conditionalonproperty如何实现刷新
当bean上有@conditionalonproperty注解时，上述的两种方案可以说失效了，因为@conditionalonproperty是一个条件注解，当不满足条件注解时，bean是没法注册到spring容器中的。如果我们要实现此种情况的下的动态刷新，我们就得自己手动注册或者销毁bean了。其实现流程如下
1、当满足条件注解时，则手动创建bean，然后配合@apolloconfigchangelistener监听该bean的属性变化。当该bean属性有变化时，手动把属性注入bean。同时刷新依赖该bean的其他bean
2、当不满足条件注解时，则手动从spring容器中移除bean，同时刷新依赖该bean的其他bean
其刷新核心代码如下
public class orderpropertiesrefresh implements applicationcontextaware {
private applicationcontext applicationcontext;
@apolloconfig(value = "order.properties")
private config config;
@apolloconfigchangelistener(value="order.properties",interestedkeyprefixes = {"order."},interestedkeys = {"model.isshoworder"})
private void refresh(configchangeevent changeevent){
for (string basepackage : listbasepackages()) {
set<class> conditionalclasses = classscannerutils.scan(basepackage, conditionalonproperty.class);
if(!collectionutils.isempty(conditionalclasses)){
for (class conditionalclass : conditionalclasses) {
conditionalonproperty conditionalonproperty = (conditionalonproperty) conditionalclass.getannotation(conditionalonproperty.class);
string[] conditionalonpropertykeys = conditionalonproperty.name();
string beanchangecondition = this.getchangekey(changeevent,conditionalonpropertykeys);
string conditionalonpropertyvalue = conditionalonproperty.havingvalue();
boolean ischangebean = this.changebean(conditionalclass, beanchangecondition, conditionalonpropertyvalue);
if(!ischangebean){
// 更新相应的bean的属性值，主要是存在@configurationproperties注解的bean
applicationcontext.publishevent(new environmentchangeevent(changeevent.changedkeys()));
}
}
}
}
printchangekeyutils.printchange(changeevent);
printallbeans();
}
/**
* 根据条件对bean进行注册或者移除
* @param conditionalclass
* @param beanchangecondition bean发生改变的条件
* @param conditionalonpropertyvalue
*/
private boolean changebean(class conditionalclass, string beanchangecondition, string conditionalonpropertyvalue) {
boolean isneedregisterbeanifkeychange = this.isneedregisterbeanifkeychange(beanchangecondition,conditionalonpropertyvalue);
boolean isneedremovebeanifkeychange = this.isneedremovebeanifkeychange(beanchangecondition,conditionalonpropertyvalue);
string beanname = stringutils.uncapitalize(conditionalclass.getsimplename());
if(isneedregisterbeanifkeychange){
boolean isalreadyregisterbean = this.isexistbean(beanname);
if(!isalreadyregisterbean){
this.registerbean(beanname,conditionalclass);
return true;
}
}else if(isneedremovebeanifkeychange){
this.unregisterbean(beanname);
return true;
}
return false;
}
/**
* bean注册
* @param beanname
* @param beanclass
*/
public void registerbean(string beanname,class beanclass) {
log.info("registerbean->beanname:{},beanclass:{}",beanname,beanclass);
beandefinitionbuilder beandefinitionburinilder = beandefinitionbuilder.genericbeandefinition(beanclass);
beandefinition beandefinition = beandefinitionburinilder.getbeandefinition();
setbeanfield(beanclass, beandefinition);
getbeandefinitionregistry().registerbeandefinition(beanname,beandefinition);
}
/**
* 设置bean字段值
* @param beanclass
* @param beandefinition
*/
private void setbeanfield(class beanclass, beandefinition beandefinition) {
configurationproperties configurationproperties = (configurationproperties) beanclass.getannotation(configurationproperties.class);
if(objectutils.isnotempty(configurationproperties)){
string prefix = configurationproperties.prefix();
for (string propertyname : config.getpropertynames()) {
string fieldprefix = prefix + ".";
if(propertyname.startswith(fieldprefix)){
string fieldname = propertyname.substring(fieldprefix.length());
string fieldval = config.getproperty(propertyname,null);
log.info("setbeanfield-->fieldname:{},fieldval:{}",fieldname,fieldval);
beandefinition.getpropertyvalues().add(fieldname,fieldval);
}
}
}
}
/**
* bean移除
* @param beanname
*/
public void unregisterbean(string beanname){
log.info("unregisterbean->beanname:{}",beanname);
getbeandefinitionregistry().removebeandefinition(beanname);
}
public <t> t getbean(string name) {
return (t) applicationcontext.getbean(name);
}
public <t> t getbean(class<t> clz) {
return (t) applicationcontext.getbean(clz);
}
public boolean isexistbean(string beanname){
return applicationcontext.containsbean(beanname);
}
public boolean isexistbean(class clz){
try {
object bean = applicationcontext.getbean(clz);
return true;
} catch (beansexception e) {
// log.error(e.getmessage(),e);
}
return false;
}
private boolean isneedregisterbeanifkeychange(string changekey,string conditionalonpropertyvalue){
if(stringutils.isempty(changekey)){
return false;
}
string apolloconfigvalue = config.getproperty(changekey,null);
return conditionalonpropertyvalue.equals(apolloconfigvalue);
}
private boolean isneedremovebeanifkeychange(string changekey,string conditionalonpropertyvalue){
if(!stringutils.isempty(changekey)){
string apolloconfigvalue = config.getproperty(changekey,null);
return !conditionalonpropertyvalue.equals(apolloconfigvalue);
}
return false;
}
private boolean ischangekey(configchangeevent changeevent,string conditionalonpropertykey){
set<string> changekeys = changeevent.changedkeys();
if(!collectionutils.isempty(changekeys) && changekeys.contains(conditionalonpropertykey)){
return true;
}
return false;
}
private string getchangekey(configchangeevent changeevent, string[] conditionalonpropertykeys){
if(arrayutils.isempty(conditionalonpropertykeys)){
return null;
}
string changekey = null;
for (string conditionalonpropertykey : conditionalonpropertykeys) {
if(ischangekey(changeevent,conditionalonpropertykey)){
changekey = conditionalonpropertykey;
break;
}
}
return changekey;
}
private beandefinitionregistry getbeandefinitionregistry(){
configurableapplicationcontext configurablecontext = (configurableapplicationcontext) applicationcontext;
beandefinitionregistry beandefinitionregistry = (defaultlistablebeanfactory) configurablecontext.getbeanfactory();
return beandefinitionregistry;
}
private list<string> listbasepackages(){
configurableapplicationcontext configurablecontext = (configurableapplicationcontext) applicationcontext;
return autoconfigurationpackages.get(configurablecontext.getbeanfactory());
}
@override
public void setapplicationcontext(applicationcontext applicationcontext) throws beansexception {
this.applicationcontext = applicationcontext;
}
public void printallbeans() {
string[] beans = applicationcontext.getbeandefinitionnames();
arrays.sort(beans);
for (string beanname : beans) {
class<?> beantype = applicationcontext.gettype(beanname);
system.out.println(beantype);
}
}
}
如果条件注解的值也是配置在apollo上，可能会出现依赖条件注解的bean的其他bean，在项目拉取apollo配置时，就已经注入spring容器中，此时就算条件注解满足条件，则引用该条件注解bean的其他bean，也会拿不到条件注解bean。此时有2种方法解决，一种是在依赖条件注解bean的其他bean注入之前，先手动注册条件注解bean到spring容器中，其核心代码如下
@component
@slf4j
public class refreshbeanfactory implements beanfactorypostprocessor {
@override
public void postprocessbeanfactory(configurablelistablebeanfactory configurablelistablebeanfactory) throws beansexception {
config config = configservice.getconfig("order.properties");
list<string> basepackages = autoconfigurationpackages.get(configurablelistablebeanfactory);
for (string basepackage : basepackages) {
set<class> conditionalclasses = classscannerutils.scan(basepackage, conditionalonproperty.class);
if(!collectionutils.isempty(conditionalclasses)){
for (class conditionalclass : conditionalclasses) {
conditionalonproperty conditionalonproperty = (conditionalonproperty) conditionalclass.getannotation(conditionalonproperty.class);
string[] conditionalonpropertykeys = conditionalonproperty.name();
string beanconditionkey = this.getconditionalonpropertykey(config,conditionalonpropertykeys);
string conditionalonpropertyvalue = conditionalonproperty.havingvalue();
this.registerbeanifmatchcondition((defaultlistablebeanfactory)configurablelistablebeanfactory,config,conditionalclass,beanconditionkey,conditionalonpropertyvalue);
}
}
}
}
private void registerbeanifmatchcondition(defaultlistablebeanfactory beanfactory,config config,class conditionalclass, string beanconditionkey, string conditionalonpropertyvalue) {
boolean isneedregisterbean = this.isneedregisterbean(config,beanconditionkey,conditionalonpropertyvalue);
string beanname = stringutils.uncapitalize(conditionalclass.getsimplename());
if(isneedregisterbean){
this.registerbean(config,beanfactory,beanname,conditionalclass);
}
}
public void registerbean(config config,defaultlistablebeanfactory beanfactory, string beanname, class beanclass) {
log.info("registerbean->beanname:{},beanclass:{}",beanname,beanclass);
beandefinitionbuilder beandefinitionburinilder = beandefinitionbuilder.genericbeandefinition(beanclass);
beandefinition beandefinition = beandefinitionburinilder.getbeandefinition();
setbeanfield(config,beanclass, beandefinition);
beanfactory.registerbeandefinition(beanname,beandefinition);
}
private void setbeanfield(config config,class beanclass, beandefinition beandefinition) {
configurationproperties configurationproperties = (configurationproperties) beanclass.getannotation(configurationproperties.class);
if(objectutils.isnotempty(configurationproperties)){
string prefix = configurationproperties.prefix();
for (string propertyname : config.getpropertynames()) {
string fieldprefix = prefix + ".";
if(propertyname.startswith(fieldprefix)){
string fieldname = propertyname.substring(fieldprefix.length());
string fieldval = config.getproperty(propertyname,null);
log.info("setbeanfield-->fieldname:{},fieldval:{}",fieldname,fieldval);
beandefinition.getpropertyvalues().add(fieldname,fieldval);
}
}
}
}
public boolean isneedregisterbean(config config,string beanconditionkey,string conditionalonpropertyvalue){
if(stringutils.isempty(beanconditionkey)){
return false;
}
string apolloconfigvalue = config.getproperty(beanconditionkey,null);
return conditionalonpropertyvalue.equals(apolloconfigvalue);
}
private string getconditionalonpropertykey(config config, string[] conditionalonpropertykeys){
if(arrayutils.isempty(conditionalonpropertykeys)){
return null;
}
string changekey = null;
for (string conditionalonpropertykey : conditionalonpropertykeys) {
if(isconditionalonpropertykey(config,conditionalonpropertykey)){
changekey = conditionalonpropertykey;
break;
}
}
return changekey;
}
private boolean isconditionalonpropertykey(config config,string conditionalonpropertykey){
set<string> propertynames = config.getpropertynames();
if(!collectionutils.isempty(propertynames) && propertynames.contains(conditionalonpropertykey)){
return true;
}
return false;
}
}
其次利用懒加载的思想，在使用条件注解bean时，使用形如下方法
order order = (order)
springcontextutils.getbean("order");
总结
本文主要介绍了常用的动态刷新，但本文的代码示例实现的功能不局限于此，本文的代码还实现如何通过自定义注解与apollo整合来实现一些业务操作，同时也实现了基于hystrix注解与apollo整合，实现基于线程隔离的动态熔断，感兴趣的朋友可以复制文末链接到浏览器，进行查看
apollo基本上是能满足我们日常的业务开发要求，但是对于一些需求，比如动态刷新线上数据库资源啥，我们还是得做一定的量的改造，好在携程也提供了apollo-use-cases，在里面可以找到常用的使用场景以及示例代码，其链接如下
感兴趣的朋友，可以查看下。
demo链接
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apollo与springboot集成实现动态刷新配置的教程详解
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