diff --git a/src/com/hippo/ehviewer/exception/FileException.java b/src/com/hippo/ehviewer/exception/FileException.java
new file mode 100644
index 000000000..ce7b7ce70
--- /dev/null
+++ b/src/com/hippo/ehviewer/exception/FileException.java
@@ -0,0 +1,25 @@
+package com.hippo.ehviewer.exception;
+
+public class FileException extends Exception {
+    
+    public static final int MKDIR_ERROR = 0x0;
+    public static final int CREATE_FILE_ERROR = 0x1;
+    public static final int NOT_DIR = 0x2;
+    public static final int NOT_FILE = 0x3;
+    public static final int CANNOT_EXECUTE = 0x4;
+    public static final int CANNOT_READ = 0x5;
+    public static final int CANNOT_WRITE = 0x6;
+    
+    private int mErrorCode;
+    
+    private static final long serialVersionUID = 1L;
+    
+    public FileException(int errorCode) {
+        mErrorCode = errorCode;
+    }
+    
+    public int getErrorCode() {
+        return mErrorCode;
+    }
+    
+}
diff --git a/src/com/hippo/ehviewer/exception/NoSdCardException.java b/src/com/hippo/ehviewer/exception/NoSdCardException.java
new file mode 100644
index 000000000..25cacff29
--- /dev/null
+++ b/src/com/hippo/ehviewer/exception/NoSdCardException.java
@@ -0,0 +1,5 @@
+package com.hippo.ehviewer.exception;
+
+public class NoSdCardException extends Exception {
+    private static final long serialVersionUID = 1L;
+}
diff --git a/src/com/hippo/ehviewer/network/Constant.java b/src/com/hippo/ehviewer/network/Constant.java
new file mode 100644
index 000000000..227abb011
--- /dev/null
+++ b/src/com/hippo/ehviewer/network/Constant.java
@@ -0,0 +1,14 @@
+package com.hippo.ehviewer.network;
+
+public class Constant {
+    
+    public static final int HTTP_TEMP_REDIRECT = 307;
+    
+    public static String defaultUserAgent = "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/32.0.1700.76 Safari/537.36";
+    public static String userAgent = System.getProperty("http.agent", defaultUserAgent);
+    public static final int DEFAULT_TIMEOUT = 5 * 1000;
+    public static final int MAX_REDIRECTS = 5;
+    
+    public static final int BUFFER_SIZE = 4096;
+    
+}