重构Rolling日志读写逻辑，解决边界条件下异常情况，优化读写性能；

xxl-job-core/src/main/java/com/xxl/job/core/log/XxlJobFileAppender.java

@@ -1,17 +1,22 @@
 package com.xxl.job.core.log;
 
 import com.xxl.job.core.openapi.model.LogResult;
+import com.xxl.tool.core.DateTool;
 import com.xxl.tool.core.StringTool;
+import com.xxl.tool.io.FileTool;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.io.*;
-import java.nio.charset.StandardCharsets;
-import java.text.SimpleDateFormat;
+import java.io.File;
+import java.io.IOException;
 import java.util.Date;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.Consumer;
 
 /**
  * store trigger log in each log-file
+ *
  * @author xuxueli 2016-3-12 19:25:12
  */
 public class XxlJobFileAppender {
@@ -31,23 +36,19 @@ public class XxlJobFileAppender {
 	private static String logBasePath = "/data/applogs/xxl-job/jobhandler";
 	private static String glueSrcPath = logBasePath.concat(File.separator).concat("gluesource");
 	private static String callbackLogPath = logBasePath.concat(File.separator).concat("callbacklogs");
-	public static void initLogPath(String logPath){
+	public static void initLogPath(String logPath) throws IOException {
 		// init
 		if (StringTool.isNotBlank(logPath)) {
 			logBasePath = logPath.trim();
 		}
 		// mk base dir
 		File logPathDir = new File(logBasePath);
-		if (!logPathDir.exists()) {
-			logPathDir.mkdirs();
-		}
+        FileTool.createDirectories(logPathDir);
 		logBasePath = logPathDir.getPath();
 
 		// mk glue dir
 		File glueBaseDir = new File(logPathDir, "gluesource");
-		if (!glueBaseDir.exists()) {
-			glueBaseDir.mkdirs();
-		}
+        FileTool.createDirectories(glueBaseDir);
 		glueSrcPath = glueBaseDir.getPath();
 	}
 	public static String getLogPath() {
@@ -63,25 +64,24 @@ public class XxlJobFileAppender {
 	/**
 	 * log filename, like "logPath/yyyy-MM-dd/9999.log"
 	 *
-	 * @param triggerDate
-	 * @param logId
-	 * @return
+	 * @param logId log id
+	 * @return      log file name
 	 */
 	public static String makeLogFileName(Date triggerDate, long logId) {
 
-		// filePath/yyyy-MM-dd
-		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");	// avoid concurrent problem, can not be static
-		File logFilePath = new File(getLogPath(), sdf.format(triggerDate));
-		if (!logFilePath.exists()) {
-			logFilePath.mkdir();
-		}
+		// "filePath/yyyy-MM-dd"
+		File logFilePath = new File(getLogPath(), DateTool.formatDate(triggerDate));
+        try {
+            FileTool.createDirectories(logFilePath);
+        } catch (IOException e) {
+            throw new RuntimeException("XxlJobFileAppender makeLogFileName error, logFilePath:"+ logFilePath.getPath(), e);
+        }
 
-		// filePath/yyyy-MM-dd/9999.log
-		String logFileName = logFilePath.getPath()
-				.concat(File.separator)
-				.concat(String.valueOf(logId))
-				.concat(".log");
-		return logFileName;
+        // filePath/yyyy-MM-dd/9999.log
+        return logFilePath.getPath()
+                .concat(File.separator)
+                .concat(String.valueOf(logId))
+                .concat(".log");
 	}
 
 	/**
@@ -92,34 +92,17 @@ public class XxlJobFileAppender {
 	 */
 	public static void appendLog(String logFileName, String appendLog) {
 
-		// log file
-		if (logFileName==null || logFileName.trim().isEmpty()) {
+		// valid
+		if (StringTool.isBlank(logFileName) || appendLog == null) {
 			return;
 		}
-		File logFile = new File(logFileName);
-		if (!logFile.exists()) {
-			try {
-				logFile.createNewFile();
-			} catch (IOException e) {
-				logger.error(e.getMessage(), e);
-				return;
-			}
-		}
 
-		// log
-		if (appendLog == null) {
-			appendLog = "";
-		}
-		appendLog += "\r\n";
-		
-		// append file content
-        try (FileOutputStream fos = new FileOutputStream(logFile, true)) {
-            fos.write(appendLog.getBytes(StandardCharsets.UTF_8));
-            fos.flush();
-        } catch (Exception e) {
-            logger.error(e.getMessage(), e);
+		// append log
+        try {
+            FileTool.writeLines(logFileName, List.of(appendLog), true);
+        } catch (IOException e) {
+            throw new RuntimeException("XxlJobFileAppender appendLog error, logFileName:"+ logFileName, e);
         }
-		
 	}
 
 	/**
@@ -129,53 +112,52 @@ public class XxlJobFileAppender {
 	 * @param fromLineNum	from line num
 	 * @return log content
 	 */
-	public static LogResult readLog(String logFileName, int fromLineNum){
+	public static LogResult readLog(String logFileName, final int fromLineNum){
 
-		// valid log file
-		if (logFileName==null || logFileName.trim().isEmpty()) {
+		// valid
+		if (StringTool.isBlank(logFileName)) {
             return new LogResult(fromLineNum, 0, "readLog fail, logFile not found", true);
 		}
-		File logFile = new File(logFileName);
-		if (!logFile.exists()) {
+		if (!FileTool.exists(logFileName)) {
             return new LogResult(fromLineNum, 0, "readLog fail, logFile not exists", true);
 		}
 
-		// read file
-		StringBuilder logContentBuilder = new StringBuilder();
-		LineNumberReader reader = null;
-		int toLineNum = 0;
-		/*int readLineCount = 0;*/
-		try {
-			reader = new LineNumberReader(new InputStreamReader(new FileInputStream(logFile), StandardCharsets.UTF_8));
-			String line = null;
-			while ((line = reader.readLine())!=null) {
-				// skip before lineNum
-				toLineNum = reader.getLineNumber();		// [from, to], start as 1
-				if (toLineNum < fromLineNum) {
-					continue;
-				}
-
-				// append log
-				logContentBuilder.append(line).append("\n");
-				// Limit return less than 1000 rows per query request	// todo
-				/*if(++readLineCount >= 5) {
-					break;
-				}*/
-			}
-		} catch (IOException e) {
-			logger.error(e.getMessage(), e);
-		} finally {
-			if (reader != null) {
-				try {
-					reader.close();
-				} catch (IOException e) {
-					logger.error(e.getMessage(), e);
-				}
-			}
-		}
+		// read data
+        StringBuilder logContentBuilder = new StringBuilder();
+        // num: [from, to], start as 1
+        AtomicInteger toLineNum = new AtomicInteger(0);
+        AtomicInteger currentLineNum = new AtomicInteger(0);
+        /*int readLineCount = 0;*/
+
+        // do read
+        try {
+            FileTool.readLines(logFileName, new Consumer<String>() {
+                @Override
+                public void accept(String line) {
+                    // refresh line num
+                    currentLineNum.incrementAndGet();
+
+                    // valid
+                    if (currentLineNum.get() < fromLineNum) {
+                        return;
+                    }
+
+                    // Limit return less than 1000 rows per query request	// todo
+                    /*if(++readLineCount >= 1000) {
+                        break;
+                    }*/
+
+                    // collect line data
+                    toLineNum.set(currentLineNum.get());
+                    logContentBuilder.append(line).append(System.lineSeparator());      // [from, to], start as 1
+                }
+            });
+        } catch (IOException e) {
+            logger.error("XxlJobFileAppender readLog error, logFileName:{}, fromLineNum:{}", logFileName, fromLineNum, e);
+        }
 
-		// result
-        return new LogResult(fromLineNum, toLineNum, logContentBuilder.toString(), false);
+        // result
+        return new LogResult(fromLineNum, toLineNum.get(), logContentBuilder.toString(), false);
 	}
 
 }