重要更新: ByteWriteFactory内部Byte[]长度改为动态初始化; 一方面在小数据量下节省字节开销;另一方面在大数据量下可以保证数据存放没问题;

xxl-job-admin/src/main/java/com/xxl/job/admin/controller/JobLogController.java

 		// base check
 		XxlJobLog log = xxlJobLogDao.load(id);
 		if (log == null) {
-			return new ReturnT<String>(500, "参数异常");
+			return new ReturnT<String>(500, "查看执行日志失败: 参数异常");
 		}
 		if (!(ResponseModel.SUCCESS.equals(log.getTriggerStatus()) || StringUtils.isNotBlank(log.getHandleStatus()))) {
-			return new ReturnT<String>(500, "调度失败，无法查看执行日志");
+			return new ReturnT<String>(500, "查看执行日志失败: 任务发起调度失败，无法查看执行日志");
 		}
 		
 		// trigger id, trigger time
 		if (ResponseModel.SUCCESS.equals(responseModel.getStatus())) {
 			return new ReturnT<String>(responseModel.getMsg());
 		} else {
-			return new ReturnT<String>(500, responseModel.getMsg());
+			return new ReturnT<String>(500, "查看执行日志失败: " + responseModel.getMsg());
 		}
 	}
 	

xxl-job-core/src/main/java/com/xxl/job/core/util/ByteWriteFactory.java

 	public ByteWriteFactory() {
 		m_byteBuf = ByteBuffer.allocate(1024 * 4);
 	}
+	public ByteWriteFactory(int capacity) {
+		m_byteBuf = ByteBuffer.allocate(capacity);
+	}
 	
 	public void writeInt(int intValue) {
 		byte[] intBytes = new byte[4];

xxl-job-core/src/main/java/com/xxl/job/core/util/XxlJobNetCommUtil.java

 		int len = ByteHexConverter.getByteLen(json);
 
 		// json to byte[]
-		ByteWriteFactory byteWriteFactory = new ByteWriteFactory();
+		ByteWriteFactory byteWriteFactory = new ByteWriteFactory(4 + len);
 		byteWriteFactory.writeInt(len);
 		byteWriteFactory.writeString(json, len);
 		byte[] bytes = byteWriteFactory.getBytes();