SpringBoot動(dòng)態(tài)更新yml文件

更新時(shí)間：2023年01月02日 08:39:40 作者：code2roc

在系統(tǒng)運(yùn)行過程中，可能由于一些配置項(xiàng)的簡單變動(dòng)需要重新打包啟停項(xiàng)目，這對(duì)于在運(yùn)行中的項(xiàng)目會(huì)造成數(shù)據(jù)丟失，客戶操作無響應(yīng)等情況發(fā)生，針對(duì)這類情況對(duì)開發(fā)框架進(jìn)行升級(jí)提供yml文件實(shí)時(shí)修改更新功能，這篇文章主要介紹了SpringBoot動(dòng)態(tài)更新yml文件

前言

項(xiàng)目依賴

項(xiàng)目基于的是2.0.0.RELEASE版本，所以snakeyaml需要單獨(dú)引入，高版本已包含在內(nèi)

        <dependency>
            <groupId>org.yaml</groupId>
            <artifactId>snakeyaml</artifactId>
            <version>1.23</version>
        </dependency>

網(wǎng)上大多數(shù)方法是引入spring-cloud-context配置組件調(diào)用ContextRefresher的refresh方法達(dá)到同樣的效果，考慮以下兩點(diǎn)未使用

開發(fā)框架使用了logback日志，引入spring-cloud-context會(huì)造成日志配置讀取錯(cuò)誤
引入spring-cloud-context會(huì)同時(shí)引入spring-boot-starter-actuator組件，會(huì)開放一些健康檢查路由及端口，需要對(duì)框架安全方面進(jìn)行額外控制

YML文件內(nèi)容獲取

讀取resource文件下的文件需要使用ClassPathResource獲取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文件內(nèi)容更新

我們獲取到y(tǒng)ml文件內(nèi)容后可視化顯示到前臺(tái)進(jìn)行展示修改，將修改后的內(nèi)容通過yaml.load方法轉(zhuǎn)換成Map結(jié)構(gòu)，再使用yaml.dumpAsMap轉(zhuǎn)換為流寫入到文件

    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();
        //字符輸出
        FileWriter fileWriter = new FileWriter(classPathResource.getFile());
        //用yaml方法把map結(jié)構(gòu)格式化為yaml文件結(jié)構(gòu)
        fileWriter.write(yaml.dumpAsMap(yamlMap));
        //刷新
        fileWriter.flush();
        //關(guān)閉流
        fileWriter.close();
    }

YML屬性刷新

yml屬性在程序中讀取使用一般有三種

使用Value注解

    @Value("${system.systemName}")
    private String systemName;

通過enviroment注入讀取

    @Autowired
    private Environment environment;
    environment.getProperty("system.systemName")

使用ConfigurationProperties注解讀取

@Component
@ConfigurationProperties(prefix = "system")
public class SystemConfig {
    private String systemName;
}

Property刷新

我們通過environment.getProperty方法讀取的配置集合實(shí)際是存儲(chǔ)在PropertySources中的，我們只需要把鍵值對(duì)全部取出存儲(chǔ)在propertyMap中，將更新后的yml文件內(nèi)容轉(zhuǎn)換成相同格式的ymlMap，兩個(gè)Map進(jìn)行合并，調(diào)用PropertySources的replace方法進(jìn)行整體替換即可

但是yaml.load后的ymlMap和PropertySources取出的propertyMap兩者數(shù)據(jù)解構(gòu)是不同的，需要進(jìn)行手動(dòng)轉(zhuǎn)換

propertyMap集合就是單純的key，value鍵值對(duì)，key是properties形式的名稱，例如system.systemName=>xxxxx集團(tuán)管理系統(tǒng)

ymlMap集合是key，LinkedHashMap的嵌套層次結(jié)構(gòu)，例如system=>(systemName=>xxxxx集團(tuán)管理系統(tǒng))

轉(zhuǎn)換方法如下

  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);
            }
        }
    }

刷新方法如下

        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

不論是Value注解還是ConfigurationProperties注解，實(shí)際都是通過注入Bean對(duì)象的屬性方法使用的，我們先自定注解RefreshValue來修飾屬性所在Bean的class

通過實(shí)現(xiàn)InstantiationAwareBeanPostProcessorAdapter接口在系統(tǒng)啟動(dòng)時(shí)過濾篩選對(duì)應(yīng)的Bean存儲(chǔ)下來，在更新yml文件時(shí)通過spring的event通知更新對(duì)應(yīng)

bean的屬性即可

注冊(cè)事件使用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);
                }
            }
        }
    }

通知觸發(fā)事件使用ApplicationContext的publishEvent方法

    @Autowired
    private ApplicationContext applicationContext;
  	for (String key : propertyMap.keySet()) {
       applicationContext.publishEvent(new YamlConfigRefreshPostProcessor.ConfigUpdateEvent(this, key));
    }

YamlConfigRefreshPostProcessor的完整代碼如下

@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);
                }
            }
        }
    }
}

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