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
@Component
public 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);
}
}
}
}
}