[alerter] 告警处理指标数据，告警表达式计算，内容模版关键字替换

alerter/src/main/java/com/usthe/alert/util/AlertTemplateUtil.java

@@ -0,0 +1,39 @@
+package com.usthe.alert.util;
+
+import lombok.extern.slf4j.Slf4j;
+
+import java.util.Map;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+ * 告警模版关键字匹配替换引擎工具
+ * @author tom
+ * @date 2021/12/10 11:53
+ */
+@Slf4j
+public class AlertTemplateUtil {
+
+    /**
+     * 匹配 ${key} 的变量
+     * eg: Alert, the instance: ${instance} metrics: ${metrics} is over flow.
+     */
+    private static final Pattern PATTERN = Pattern.compile("\\$\\{(\\w+)\\}");
+
+    public static String render(String template, Map<String, Object> replaceData) {
+        try {
+            Matcher matcher = PATTERN.matcher(template);
+            StringBuffer buffer = new StringBuffer();
+            while (matcher.find()) {
+                Object objectValue = replaceData.getOrDefault(matcher.group(1), "NullValue");
+                String value = objectValue.toString();
+                matcher.appendReplacement(buffer, value);
+            }
+            matcher.appendTail(buffer);
+            return buffer.toString();
+        } catch (Exception e) {
+            log.error(e.getMessage(), e);
+            return template;
+        }
+    }
+}