hash & sm4 & cert(未测试)

src/main/java/util/FileUtil.java

@@ -0,0 +1,33 @@
+package util;
+
+import java.io.IOException;
+import java.io.RandomAccessFile;
+
+public class FileUtil {
+    public static void writeFile(String filePath, byte[] data) throws IOException {
+        RandomAccessFile raf = null;
+        try {
+            raf = new RandomAccessFile(filePath, "rw");
+            raf.write(data);
+        } finally {
+            if (raf != null) {
+                raf.close();
+            }
+        }
+    }
+
+    public static byte[] readFile(String filePath) throws IOException {
+        RandomAccessFile raf = null;
+        byte[] data;
+        try {
+            raf = new RandomAccessFile(filePath, "r");
+            data = new byte[(int) raf.length()];
+            raf.read(data);
+            return data;
+        } finally {
+            if (raf != null) {
+                raf.close();
+            }
+        }
+    }
+}