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目录前言项目依赖YML文件内容获取YML文件内容更新YML属性刷新Property刷新注解刷新前言 在系统运行过程中，可能由于一些配置项的简单变动需要重新打包启停项目，这对于在运行中
在系统运行过程中，可能由于一些配置项的简单变动需要重新打包启停项目，这对于在运行中的项目会造成数据丢失，客户操作无响应等情况发生，针对这类情况对开发框架进行升级提供yml文件实时修改更新功能
项目基于的是2.0.0.RELEASE版本，所以snakeyaml需要单独引入，高版本已包含在内
<dependency>
<groupId>org.yaml</groupId>
<artifactId>snakeyaml</artifactId>
<version>1.23</version>
</dependency>
网上大多数方法是引入spring-cloud-context配置组件调用ContextRefresher的refresh方法达到同样的效果，考虑以下两点未使用
读取resource文件下的文件需要使用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");
}
我们获取到yml文件内容后可视化显示到前台进行展示修改，将修改后的内容通过yaml.load方法转换成Map结构，再使用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();
//字符输出
FileWriter fileWriter = new FileWriter(classPathResource.getFile());
//用yaml方法把map结构格式化为yaml文件结构
fileWriter.write(yaml.dumpAsMap(yamlMap));
//刷新
fileWriter.flush();
//关闭流
fileWriter.close();
}
yml属性在程序中读取使用一般有三种
使用Value注解
@Value("${system.systemName}")
private String systemName;
通过enviroment注入读取
@Autowired
private Environment environment;
environment.getProperty("system.systemName")
使用ConfigurationProperties注解读取
@Component
@ConfigurationProperties(prefix = "system")
public class SystemConfig {
private String systemName;
}
我们通过environment.getProperty方法读取的配置集合实际是存储在PropertySources中的，我们只需要把键值对全部取出存储在propertyMap中，将更新后的yml文件内容转换成相同格式的ymlMap，两个Map进行合并，调用PropertySources的replace方法进行整体替换即可
但是yaml.load后的ymlMap和PropertySources取出的propertyMap两者数据解构是不同的，需要进行手动转换
propertyMap集合就是单纯的key，value键值对，key是properties形式的名称，例如system.systemName=>xxxxx集团管理系统
ymlMap集合是key，LinkedHashMap的嵌套层次结构，例如system=>(systemName=>xxxxx集团管理系统)
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));不论是Value注解还是ConfigurationProperties注解，实际都是通过注入Bean对象的属性方法使用的，我们先自定注解RefreshValue来修饰属性所在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通知更新对应
bean的属性即可
注册事件使用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);
}
}
}
}
通知触发事件使用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);
}
}
}
}
}到此这篇关于SpringBoot动态更新yml文件的文章就介绍到这了,更多相关SpringBoot更新yml内容请搜索编程网以前的文章或继续浏览下面的相关文章希望大家以后多多支持编程网！
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本文标题: SpringBoot动态更新yml文件
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