diff --git a/docs/java/io/io-basis.md b/docs/java/io/io-basis.md
index 16c83303ecf..910532b32e9 100755
--- a/docs/java/io/io-basis.md
+++ b/docs/java/io/io-basis.md
@@ -305,15 +305,14 @@ BufferedInputStream bufferedInputStream = new BufferedInputStream(new FileInputS
 
 ```java
 @Test
-void copy_pdf_to_another_pdf_with_byte_array_buffer_stream() {
+void copy_pdf_to_another_pdf_buffer_stream() {
     // 记录开始时间
     long start = System.currentTimeMillis();
     try (BufferedInputStream bis = new BufferedInputStream(new FileInputStream("深入理解计算机操作系统.pdf"));
          BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream("深入理解计算机操作系统-副本.pdf"))) {
-        int len;
-        byte[] bytes = new byte[4 * 1024];
-        while ((len = bis.read(bytes)) != -1) {
-            bos.write(bytes, 0, len);
+        int content;
+        while ((content = bis.read()) != -1) {
+            bos.write(content);
         }
     } catch (IOException e) {
         e.printStackTrace();
@@ -324,15 +323,14 @@ void copy_pdf_to_another_pdf_with_byte_array_buffer_stream() {
 }
 
 @Test
-void copy_pdf_to_another_pdf_with_byte_array_stream() {
+void copy_pdf_to_another_pdf_stream() {
     // 记录开始时间
     long start = System.currentTimeMillis();
     try (FileInputStream fis = new FileInputStream("深入理解计算机操作系统.pdf");
          FileOutputStream fos = new FileOutputStream("深入理解计算机操作系统-副本.pdf")) {
-        int len;
-        byte[] bytes = new byte[4 * 1024];
-        while ((len = fis.read(bytes)) != -1) {
-            fos.write(bytes, 0, len);
+        int content;
+        while ((content = fis.read()) != -1) {
+            fos.write(content);
         }
     } catch (IOException e) {
         e.printStackTrace();
@@ -358,14 +356,15 @@ void copy_pdf_to_another_pdf_with_byte_array_stream() {
 
 ```java
 @Test
-void copy_pdf_to_another_pdf_buffer_stream() {
+void copy_pdf_to_another_pdf_with_byte_array_buffer_stream() {
     // 记录开始时间
     long start = System.currentTimeMillis();
     try (BufferedInputStream bis = new BufferedInputStream(new FileInputStream("深入理解计算机操作系统.pdf"));
          BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream("深入理解计算机操作系统-副本.pdf"))) {
-        int content;
-        while ((content = bis.read()) != -1) {
-            bos.write(content);
+        int len;
+        byte[] bytes = new byte[4 * 1024];
+        while ((len = bis.read(bytes)) != -1) {
+            bos.write(bytes, 0, len);
         }
     } catch (IOException e) {
         e.printStackTrace();
@@ -376,14 +375,15 @@ void copy_pdf_to_another_pdf_buffer_stream() {
 }
 
 @Test
-void copy_pdf_to_another_pdf_stream() {
+void copy_pdf_to_another_pdf_with_byte_array_stream() {
     // 记录开始时间
     long start = System.currentTimeMillis();
     try (FileInputStream fis = new FileInputStream("深入理解计算机操作系统.pdf");
          FileOutputStream fos = new FileOutputStream("深入理解计算机操作系统-副本.pdf")) {
-        int content;
-        while ((content = fis.read()) != -1) {
-            fos.write(content);
+        int len;
+        byte[] bytes = new byte[4 * 1024];
+        while ((len = fis.read(bytes)) != -1) {
+            fos.write(bytes, 0, len);
         }
     } catch (IOException e) {
         e.printStackTrace();