日志输出区别错误和普通日志。在console输出时，错误日志使用system.err输出。

skywalking-collector/skywalking-api/src/main/java/com/ai/cloud/skywalking/logging/IWriter.java

@@ -2,4 +2,6 @@ package com.ai.cloud.skywalking.logging;
 
 public interface IWriter {
     void write(String message);
+
+    void writeError(String message);
 }

skywalking-collector/skywalking-api/src/main/java/com/ai/cloud/skywalking/logging/Logger.java

@@ -23,11 +23,15 @@ public class Logger {
         StackTraceElement locations[] = dummyException.getStackTrace();
 
         if (locations != null && locations.length > 2) {
-            WriterFactory.getLogWriter().write(formatMessage(level, message, locations[2]));
+            if(ERROR.equals(level) || WARN.equals(level)){
+                WriterFactory.getLogWriter().writeError(formatMessage(level, message, locations[2]));
+            }else {
+                WriterFactory.getLogWriter().write(formatMessage(level, message, locations[2]));
+            }
         }
 
         if (e != null) {
-            WriterFactory.getLogWriter().write(LoggingUtil.fetchThrowableStack(e));
+            WriterFactory.getLogWriter().writeError(LoggingUtil.fetchThrowableStack(e));
         }
     }
 

skywalking-collector/skywalking-api/src/main/java/com/ai/cloud/skywalking/logging/STDOutWriter.java

@@ -5,6 +5,11 @@ public class STDOutWriter implements IWriter {
 
     @Override
     public void write(String message) {
+        System.out.println(message);
+    }
+
+    @Override
+    public void writeError(String message) {
         System.err.println(message);
     }
 }

skywalking-collector/skywalking-api/src/main/java/com/ai/cloud/skywalking/logging/SyncFileWriter.java

@@ -48,6 +48,11 @@ public class SyncFileWriter implements IWriter {
         switchLogFileIfNecessary();
     }
 
+    @Override
+    public void writeError(String message) {
+        this.write(message);
+    }
+
     private void writeLogRecord(String message) {
         try {
             os.write(message.getBytes());