前言
在零碎运行过程中，可能因为一些配置项的简略变动须要从新打包启停我的项目，这对于在运行中的我的项目会造成数据失落，客户操作无响应等状况产生，针对这类状况对开发框架进行降级提供yml文件实时批改更新性能
我的项目依赖
我的项目基于的是2.0.0.RELEASE版本，所以snakeyaml须要独自引入，高版本已蕴含在内
<dependency> <groupId>org.yaml</groupId> <artifactId>snakeyaml</artifactId> <version>1.23</version> </dependency>网上大多数办法是引入spring-cloud-context配置组件调用ContextRefresher的refresh办法达到同样的成果，思考以下两点未应用
- 开发框架应用了logback日志，引入spring-cloud-context会造成日志配置读取谬误
- 引入spring-cloud-context会同时引入spring-boot-starter-actuator组件，会凋谢一些健康检查路由及端口，须要对框架平安方面进行额定管制
YML文件内容获取
读取resource文件下的文件须要应用ClassPathResource获取InputStream
public String getTotalYamlFileContent() throws Exception { String fileName = "application.yml"; return getYamlFileContent(fileName); } public String getYamlFileContent(String fileName) throws Exception { ClassPathResource classPathResource = new ClassPathResource(fileName); return onvertStreamToString(classPathResource.getInputStream()); } public static String convertStreamToString(InputStream inputStream) throws Exception{ return IOUtils.toString(inputStream, "utf-8"); }YML文件内容更新
咱们获取到yml文件内容后可视化显示到前台进行展现批改，将批改后的内容通过yaml.load办法转换成Map构造，再应用yaml.dumpAsMap转换为流写入到文件
public void updateTotalYamlFileContent(String content) throws Exception { String fileName = "application.yml"; updateYamlFileContent(fileName, content); } public void updateYamlFileContent(String fileName, String content) throws Exception { Yaml template = new Yaml(); Map<String, Object> yamlMap = template.load(content); ClassPathResource classPathResource = new ClassPathResource(fileName); Yaml yaml = new Yaml(); //字符输入 FileWriter fileWriter = new FileWriter(classPathResource.getFile()); //用yaml办法把map构造格式化为yaml文件构造 fileWriter.write(yaml.dumpAsMap(yamlMap)); //刷新 fileWriter.flush(); //敞开流 fileWriter.close(); }YML属性刷新
yml属性在程序中读取应用个别有三种
- 应用Value注解
@Value("${system.systemName}") private String systemName;- 通过enviroment注入读取
@Autowired private Environment environment; environment.getProperty("system.systemName")- 应用ConfigurationProperties注解读取
@Component@ConfigurationProperties(prefix = "system")public class SystemConfig { private String systemName;}Property刷新
咱们通过environment.getProperty办法读取的配置汇合理论是存储在PropertySources中的，咱们只须要把键值对全副取出存储在propertyMap中，将更新后的yml文件内容转换成雷同格局的ymlMap，两个Map进行合并，调用PropertySources的replace办法进行整体替换即可
然而yaml.load后的ymlMap和PropertySources取出的propertyMap两者数据解构是不同的，须要进行手动转换
propertyMap汇合就是单纯的key，value键值对，key是properties模式的名称，例如system.systemName=>xxxxx团体管理系统
ymlMap汇合是key，LinkedHashMap的嵌套层次结构，例如system=>(systemName=>xxxxx团体管理系统)
- 转换方法如下
public HashMap<String, Object> convertYmlMapToPropertyMap(Map<String, Object> yamlMap) { HashMap<String, Object> propertyMap = new HashMap<String, Object>(); for (String key : yamlMap.keySet()) { String keyName = key; Object value = yamlMap.get(key); if (value != null && value.getClass() == LinkedHashMap.class) { convertYmlMapToPropertyMapSub(keyName, ((LinkedHashMap<String, Object>) value), propertyMap); } else { propertyMap.put(keyName, value); } } return propertyMap; } private void convertYmlMapToPropertyMapSub(String keyName, LinkedHashMap<String, Object> submMap, Map<String, Object> propertyMap) { for (String key : submMap.keySet()) { String newKey = keyName + "." + key; Object value = submMap.get(key); if (value != null && value.getClass() == LinkedHashMap.class) { convertYmlMapToPropertyMapSub(newKey, ((LinkedHashMap<String, Object>) value), propertyMap); } else { propertyMap.put(newKey, value); } } }- 刷新办法如下
String name = "applicationConfig: [classpath:/" + fileName + "]"; MapPropertySource propertySource = (MapPropertySource) environment.getPropertySources().get(name); Map<String, Object> source = propertySource.getSource(); Map<String, Object> map = new HashMap<>(source.size()); map.putAll(source); Map<String, Object> propertyMap = convertYmlMapToPropertyMap(yamlMap); for (String key : propertyMap.keySet()) { Object value = propertyMap.get(key); map.put(key, value); } environment.getPropertySources().replace(name, new MapPropertySource(name, map));注解刷新
不论是Value注解还是ConfigurationProperties注解，理论都是通过注入Bean对象的属性办法应用的，咱们先自定注解RefreshValue来润饰属性所在Bean的class
通过实现InstantiationAwareBeanPostProcessorAdapter接口在系统启动时过滤筛选对应的Bean存储下来，在更新yml文件时通过spring的event告诉更新对应
bean的属性即可
- 注册事件应用EventListener注解
@EventListener public void updateConfig(ConfigUpdateEvent configUpdateEvent) { if(mapper.containsKey(configUpdateEvent.key)){ List<FieldPair> fieldPairList = mapper.get(configUpdateEvent.key); if(fieldPairList.size()>0){ for (FieldPair fieldPair:fieldPairList) { fieldPair.updateValue(environment); } } } }- 告诉触发事件应用ApplicationContext的publishEvent办法
@Autowired private ApplicationContext applicationContext; for (String key : propertyMap.keySet()) { applicationContext.publishEvent(new YamlConfigRefreshPostProcessor.ConfigUpdateEvent(this, key)); }YamlConfigRefreshPostProcessor的残缺代码如下
@Componentpublic class YamlConfigRefreshPostProcessor extends InstantiationAwareBeanPostProcessorAdapter implements EnvironmentAware { private Map<String, List<FieldPair>> mapper = new HashMap<>(); private Environment environment; @Override public boolean postProcessAfterInstantiation(Object bean, String beanName) throws BeansException { processMetaValue(bean); return super.postProcessAfterInstantiation(bean, beanName); } @Override public void setEnvironment(Environment environment) { this.environment = environment; } private void processMetaValue(Object bean) { Class clz = bean.getClass(); if (!clz.isAnnotationPresent(RefreshValue.class)) { return; } if (clz.isAnnotationPresent(ConfigurationProperties.class)) { //@ConfigurationProperties注解 ConfigurationProperties config = (ConfigurationProperties) clz.getAnnotation(ConfigurationProperties.class); for (Field field : clz.getDeclaredFields()) { String key = config.prefix() + "." + field.getName(); if(mapper.containsKey(key)){ mapper.get(key).add(new FieldPair(bean, field, key)); }else{ List<FieldPair> fieldPairList = new ArrayList<>(); fieldPairList.add(new FieldPair(bean, field, key)); mapper.put(key, fieldPairList); } } } else { //@Valuez注解 try { for (Field field : clz.getDeclaredFields()) { if (field.isAnnotationPresent(Value.class)) { Value val = field.getAnnotation(Value.class); String key = val.value().replace("${", "").replace("}", ""); if(mapper.containsKey(key)){ mapper.get(key).add(new FieldPair(bean, field, key)); }else{ List<FieldPair> fieldPairList = new ArrayList<>(); fieldPairList.add(new FieldPair(bean, field, key)); mapper.put(key, fieldPairList); } } } } catch (Exception e) { e.printStackTrace(); System.exit(-1); } } } public static class FieldPair { private static PropertyPlaceholderHelper propertyPlaceholderHelper = new PropertyPlaceholderHelper("${", "}", ":", true); private Object bean; private Field field; private String value; public FieldPair(Object bean, Field field, String value) { this.bean = bean; this.field = field; this.value = value; } public void updateValue(Environment environment) { boolean access = field.isAccessible(); if (!access) { field.setAccessible(true); } try { if (field.getType() == String.class) { String updateVal = environment.getProperty(value); field.set(bean, updateVal); } else if (field.getType() == Integer.class) { Integer updateVal = environment.getProperty(value,Integer.class); field.set(bean, updateVal); } else if (field.getType() == int.class) { int updateVal = environment.getProperty(value,int.class); field.set(bean, updateVal); } else if (field.getType() == Boolean.class) { Boolean updateVal = environment.getProperty(value,Boolean.class); field.set(bean, updateVal); } else if (field.getType() == boolean.class) { boolean updateVal = environment.getProperty(value,boolean.class); field.set(bean, updateVal); } else { String updateVal = environment.getProperty(value); field.set(bean, JSONObject.parseObject(updateVal, field.getType())); } } catch (IllegalAccessException e) { e.printStackTrace(); } field.setAccessible(access); } public Object getBean() { return bean; } public void setBean(Object bean) { this.bean = bean; } public Field getField() { return field; } public void setField(Field field) { this.field = field; } public String getValue() { return value; } public void setValue(String value) { this.value = value; } } public static class ConfigUpdateEvent extends ApplicationEvent { String key; public ConfigUpdateEvent(Object source, String key) { super(source); this.key = key; } } @EventListener public void updateConfig(ConfigUpdateEvent configUpdateEvent) { if(mapper.containsKey(configUpdateEvent.key)){ List<FieldPair> fieldPairList = mapper.get(configUpdateEvent.key); if(fieldPairList.size()>0){ for (FieldPair fieldPair:fieldPairList) { fieldPair.updateValue(environment); } } } }}