diff --git a/mica-core/src/main/java/net/dreamlu/mica/core/utils/FileUtil.java b/mica-core/src/main/java/net/dreamlu/mica/core/utils/FileUtil.java
index 410200faf3cf856d2ca44fd995e0f213d15ea36e..fa634f01e561ab470798de7b629df30677a0c02a 100644
--- a/mica-core/src/main/java/net/dreamlu/mica/core/utils/FileUtil.java
+++ b/mica-core/src/main/java/net/dreamlu/mica/core/utils/FileUtil.java
@@ -29,6 +29,7 @@ import java.nio.charset.Charset;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
+import java.nio.file.StandardOpenOption;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -299,8 +300,8 @@ public class FileUtil extends org.springframework.util.FileCopyUtils {
 	 * @return the file contents, never {@code null}
 	 */
 	public static String readToString(final File file, final Charset encoding) {
-		try (InputStream in = Files.newInputStream(file.toPath())) {
-			return IoUtil.readToString(in, encoding);
+		try {
+			return Files.readString(file.toPath(), encoding);
 		} catch (IOException e) {
 			throw Exceptions.unchecked(e);
 		}
@@ -314,8 +315,8 @@ public class FileUtil extends org.springframework.util.FileCopyUtils {
 	 * @return the file contents, never {@code null}
 	 */
 	public static byte[] readToByteArray(final File file) {
-		try (InputStream in = Files.newInputStream(file.toPath())) {
-			return IoUtil.readToByteArray(in);
+		try {
+			return Files.readAllBytes(file.toPath());
 		} catch (IOException e) {
 			throw Exceptions.unchecked(e);
 		}
@@ -364,8 +365,12 @@ public class FileUtil extends org.springframework.util.FileCopyUtils {
 	 *                 end of the file rather than overwriting
 	 */
 	public static void writeToFile(final File file, final String data, final Charset encoding, final boolean append) {
-		try (OutputStream out = new FileOutputStream(file, append)) {
-			IoUtil.write(data, out, encoding);
+		try {
+			if (append) {
+				Files.writeString(file.toPath(), data, encoding, StandardOpenOption.CREATE, StandardOpenOption.APPEND);
+			} else {
+				Files.writeString(file.toPath(), data, encoding, StandardOpenOption.CREATE, StandardOpenOption.TRUNCATE_EXISTING, StandardOpenOption.WRITE);
+			}
 		} catch (IOException e) {
 			throw Exceptions.unchecked(e);
 		}
diff --git a/mica-core/src/main/java/net/dreamlu/mica/core/utils/PathUtil.java b/mica-core/src/main/java/net/dreamlu/mica/core/utils/PathUtil.java
index 76a1106d0643ccb70a57b25a427be10b31ccca40..4fa28e011002dfea9b81d4c6eed73c38674724df 100644
--- a/mica-core/src/main/java/net/dreamlu/mica/core/utils/PathUtil.java
+++ b/mica-core/src/main/java/net/dreamlu/mica/core/utils/PathUtil.java
@@ -47,7 +47,7 @@ public class PathUtil {
 	}
 
 	@Nullable
-	public static String toFilePath(@Nullable URL url) {
+	private static String toFilePath(@Nullable URL url) {
 		if (url == null) { return null; }
 		String protocol = url.getProtocol();
 		String file = UrlUtil.decode(url.getPath(), Charsets.UTF_8);
diff --git a/mica-core/src/main/java/net/dreamlu/mica/core/utils/RuntimeUtil.java b/mica-core/src/main/java/net/dreamlu/mica/core/utils/RuntimeUtil.java
index 40c7d7c40cdb0f0015b2613876fc8c228ce01f65..908704c10feae1bf9b0ef351f3fa77326ffa1b15 100644
--- a/mica-core/src/main/java/net/dreamlu/mica/core/utils/RuntimeUtil.java
+++ b/mica-core/src/main/java/net/dreamlu/mica/core/utils/RuntimeUtil.java
@@ -52,7 +52,7 @@ public class RuntimeUtil {
 			pId = NumberUtil.toInt(jvmName.substring(0, index), -1);
 			return pId;
 		}
-		return -1;
+		return pId;
 	}
 
 	/**
diff --git a/mica-core/src/main/java/net/dreamlu/mica/core/utils/ThreadLocalUtil.java b/mica-core/src/main/java/net/dreamlu/mica/core/utils/ThreadLocalUtil.java
index d336d552bd59789e3cf79685c70b3297aaf4e607..e1d49dd687e53903bb91836e1b3d9cde021611f6 100644
--- a/mica-core/src/main/java/net/dreamlu/mica/core/utils/ThreadLocalUtil.java
+++ b/mica-core/src/main/java/net/dreamlu/mica/core/utils/ThreadLocalUtil.java
@@ -128,6 +128,7 @@ public class ThreadLocalUtil {
 	 * @see this#get(String)
 	 * @see this#remove(String)
 	 */
+	@Nullable
 	public static <T> T getAndRemove(String key) {
 		try {
 			return get(key);
diff --git a/mica-core/src/test/java/net/dreamlu/mica/test/utils/FileTest.java b/mica-core/src/test/java/net/dreamlu/mica/test/utils/FileTest.java
index 4273039f0752e6cf5667d0d5a77889a093a26be1..48fc826b832325dadd678093f4ce76b92d311e9d 100644
--- a/mica-core/src/test/java/net/dreamlu/mica/test/utils/FileTest.java
+++ b/mica-core/src/test/java/net/dreamlu/mica/test/utils/FileTest.java
@@ -4,6 +4,8 @@ import net.dreamlu.mica.core.utils.FileUtil;
 import org.junit.Assert;
 import org.junit.Test;
 
+import java.io.File;
+
 /**
  * 文件测试
  *
@@ -21,4 +23,21 @@ public class FileTest {
 		String pathWithoutExtension = FileUtil.getPathWithoutExtension(fileName);
 		Assert.assertEquals("123123123.xx", pathWithoutExtension);
 	}
+
+	@Test
+	public void test2() {
+		String data = "123哈哈";
+		String testFilePath = FileUtil.getTempDirPath() + File.separator + "1.txt";
+		File testFile = new File(testFilePath);
+		FileUtil.writeToFile(testFile, data, false);
+		String read1 = FileUtil.readToString(testFile);
+		Assert.assertEquals(data, read1);
+		String read2 = FileUtil.readToString(testFile);
+		Assert.assertEquals(data, read2);
+		FileUtil.writeToFile(testFile, data, true);
+		String read3 = FileUtil.readToString(testFile);
+		Assert.assertEquals(data + data, read3);
+		testFile.deleteOnExit();
+	}
+
 }