Rebuild code and add default filter.

burp/file/FileExists.java

@@ -0,0 +1,18 @@
+package burp.file;
+
+import java.io.File;
+
+public class FileExists {
+	
+	/*
+	 * 判断文件是否存在
+	 */
+	public Boolean fileExists(String fileName) {
+		 File file = new File(fileName);
+		 if(file.exists()){
+			 return true;
+		 }
+		 return false;
+	}
+	
+}