public class FileUtils {
public final static String FILE_EXTENSION_SEPARATOR = ".";
private FileUtils() {
throw new AssertionError();
}
/**
* read file
*
* @param filePath
* @param charsetName The name of a supported {@link java.nio.charset.Charset </code>charset<code>}
* @return if file not exist, return null, else return content of file
* @throws RuntimeException if an error occurs while operator BufferedReader
*/
public static StringBuilder readFile(String filePath, String charsetName) {
File file = new File(filePath);
StringBuilder fileContent = new StringBuilder("");
if (file == null || !file.isFile()) {
return null;
}
BufferedReader reader = null;
try {
InputStreamReader is = new InputStreamReader(new FileInputStream(file), charsetName);
reader = new BufferedReader(is);
String line = null;
while ((line = reader.readLine()) != null) {
if (!fileContent.toString().equals("")) {
fileContent.append("\r\n");
}
fileContent.append(line);
}
return fileContent;
} catch (IOException e) {
throw new RuntimeException("IOException occurred. ", e);
} finally {
IOUtils.close(reader);
}
}
/**
* write file
*
* @param filePath
* @param content
* @param append is append, if true, write to the end of file, else clear content of file and write into it
* @return return false if content is empty, true otherwise
* @throws RuntimeException if an error occurs while operator FileWriter
*/
public static boolean writeFile(String filePath, String content, boolean append) {
if (StringUtils.isEmpty(content)) {
return false;
}
FileWriter fileWriter = null;
try {
makeDirs(filePath);
fileWriter = new FileWriter(filePath, append);
fileWriter.write(content);
return true;
} catch (IOException e) {
throw new RuntimeException("IOException occurred. ", e);
} finally {
IOUtils.close(fileWriter);
}
}
/**
* write file
*
* @param filePath
* @param contentList
* @param append is append, if true, write to the end of file, else clear content of file and write into it
* @return return false if contentList is empty, true otherwise
* @throws RuntimeException if an error occurs while operator FileWriter
*/
public static boolean writeFile(String filePath, List<String> contentList, boolean append) {
if (ListUtils.isEmpty(contentList)) {
return false;
}
FileWriter fileWriter = null;
try {
makeDirs(filePath);
fileWriter = new FileWriter(filePath, append);
int i = ;
for (String line : contentList) {
if (i++ > ) {
fileWriter.write("\r\n");
}
fileWriter.write(line);
}
return true;
} catch (IOException e) {
throw new RuntimeException("IOException occurred. ", e);
} finally {
IOUtils.close(fileWriter);
}
}
/**
* write file, the string will be written to the begin of the file
*
* @param filePath
* @param content
* @return
*/
public static boolean writeFile(String filePath, String content) {
return writeFile(filePath, content, false);
}
/**
* write file, the string list will be written to the begin of the file
*
* @param filePath
* @param contentList
* @return
*/
public static boolean writeFile(String filePath, List<String> contentList) {
return writeFile(filePath, contentList, false);
}
/**
* write file, the bytes will be written to the begin of the file
*
* @param filePath
* @param stream
* @return
* @see {@link #writeFile(String, InputStream, boolean)}
*/
public static boolean writeFile(String filePath, InputStream stream) {
return writeFile(filePath, stream, false);
}
/**
* write file
*
* @param file the file to be opened for writing.
* @param stream the input stream
* @param append if <code>true</code>, then bytes will be written to the end of the file rather than the beginning
* @return return true
* @throws RuntimeException if an error occurs while operator FileOutputStream
*/
public static boolean writeFile(String filePath, InputStream stream, boolean append) {
return writeFile(filePath != null ? new File(filePath) : null, stream, append);
}
/**
* write file, the bytes will be written to the begin of the file
*
* @param file
* @param stream
* @return
* @see {@link #writeFile(File, InputStream, boolean)}
*/
public static boolean writeFile(File file, InputStream stream) {
return writeFile(file, stream, false);
}
/**
* write file
*
* @param file the file to be opened for writing.
* @param stream the input stream
* @param append if <code>true</code>, then bytes will be written to the end of the file rather than the beginning
* @return return true
* @throws RuntimeException if an error occurs while operator FileOutputStream
*/
public static boolean writeFile(File file, InputStream stream, boolean append) {
OutputStream o = null;
try {
makeDirs(file.getAbsolutePath());
o = new FileOutputStream(file, append);
byte data[] = new byte[];
int length = -;
while ((length = stream.read(data)) != -) {
o.write(data, , length);
}
o.flush();
return true;
} catch (FileNotFoundException e) {
throw new RuntimeException("FileNotFoundException occurred. ", e);
} catch (IOException e) {
throw new RuntimeException("IOException occurred. ", e);
} finally {
IOUtils.close(o);
IOUtils.close(stream);
}
}
/**
* move file
*
* @param sourceFilePath
* @param destFilePath
*/
public static void moveFile(String sourceFilePath, String destFilePath) {
if (TextUtils.isEmpty(sourceFilePath) || TextUtils.isEmpty(destFilePath)) {
throw new RuntimeException("Both sourceFilePath and destFilePath cannot be null.");
}
moveFile(new File(sourceFilePath), new File(destFilePath));
}
/**
* move file
*
* @param srcFile
* @param destFile
*/
public static void moveFile(File srcFile, File destFile) {
boolean rename = srcFile.renameTo(destFile);
if (!rename) {
copyFile(srcFile.getAbsolutePath(), destFile.getAbsolutePath());
deleteFile(srcFile.getAbsolutePath());
}
}
/**
* copy file
*
* @param sourceFilePath
* @param destFilePath
* @return
* @throws RuntimeException if an error occurs while operator FileOutputStream
*/
public static boolean copyFile(String sourceFilePath, String destFilePath) {
InputStream inputStream = null;
try {
inputStream = new FileInputStream(sourceFilePath);
} catch (FileNotFoundException e) {
throw new RuntimeException("FileNotFoundException occurred. ", e);
}
return writeFile(destFilePath, inputStream);
}
/**
* read file to string list, a element of list is a line
*
* @param filePath
* @param charsetName The name of a supported {@link java.nio.charset.Charset </code>charset<code>}
* @return if file not exist, return null, else return content of file
* @throws RuntimeException if an error occurs while operator BufferedReader
*/
public static List<String> readFileToList(String filePath, String charsetName) {
File file = new File(filePath);
List<String> fileContent = new ArrayList<String>();
if (file == null || !file.isFile()) {
return null;
}
BufferedReader reader = null;
try {
InputStreamReader is = new InputStreamReader(new FileInputStream(file), charsetName);
reader = new BufferedReader(is);
String line = null;
while ((line = reader.readLine()) != null) {
fileContent.add(line);
}
return fileContent;
} catch (IOException e) {
throw new RuntimeException("IOException occurred. ", e);
} finally {
IOUtils.close(reader);
}
}
/**
* get file name from path, not include suffix
*
* <pre>
* getFileNameWithoutExtension(null) = null
* getFileNameWithoutExtension("") = ""
* getFileNameWithoutExtension(" ") = " "
* getFileNameWithoutExtension("abc") = "abc"
* getFileNameWithoutExtension("a.mp") = "a"
* getFileNameWithoutExtension("a.b.rmvb") = "a.b"
* getFileNameWithoutExtension("c:\\") = ""
* getFileNameWithoutExtension("c:\\a") = "a"
* getFileNameWithoutExtension("c:\\a.b") = "a"
* getFileNameWithoutExtension("c:a.txt\\a") = "a"
* getFileNameWithoutExtension("/home/admin") = "admin"
* getFileNameWithoutExtension("/home/admin/a.txt/b.mp") = "b"
* </pre>
*
* @param filePath
* @return file name from path, not include suffix
* @see
*/
public static String getFileNameWithoutExtension(String filePath) {
if (StringUtils.isEmpty(filePath)) {
return filePath;
}
int extenPosi = filePath.lastIndexOf(FILE_EXTENSION_SEPARATOR);
int filePosi = filePath.lastIndexOf(File.separator);
if (filePosi == -) {
return (extenPosi == - ? filePath : filePath.substring(, extenPosi));
}
if (extenPosi == -) {
return filePath.substring(filePosi + );
}
return (filePosi < extenPosi ? filePath.substring(filePosi + , extenPosi) : filePath.substring(filePosi + ));
}
/**
* get file name from path, include suffix
*
* <pre>
* getFileName(null) = null
* getFileName("") = ""
* getFileName(" ") = " "
* getFileName("a.mp") = "a.mp"
* getFileName("a.b.rmvb") = "a.b.rmvb"
* getFileName("abc") = "abc"
* getFileName("c:\\") = ""
* getFileName("c:\\a") = "a"
* getFileName("c:\\a.b") = "a.b"
* getFileName("c:a.txt\\a") = "a"
* getFileName("/home/admin") = "admin"
* getFileName("/home/admin/a.txt/b.mp") = "b.mp"
* </pre>
*
* @param filePath
* @return file name from path, include suffix
*/
public static String getFileName(String filePath) {
if (StringUtils.isEmpty(filePath)) {
return filePath;
}
int filePosi = filePath.lastIndexOf(File.separator);
return (filePosi == -) ? filePath : filePath.substring(filePosi + );
}
/**
* get folder name from path
*
* <pre>
* getFolderName(null) = null
* getFolderName("") = ""
* getFolderName(" ") = ""
* getFolderName("a.mp") = ""
* getFolderName("a.b.rmvb") = ""
* getFolderName("abc") = ""
* getFolderName("c:\\") = "c:"
* getFolderName("c:\\a") = "c:"
* getFolderName("c:\\a.b") = "c:"
* getFolderName("c:a.txt\\a") = "c:a.txt"
* getFolderName("c:a\\b\\c\\d.txt") = "c:a\\b\\c"
* getFolderName("/home/admin") = "/home"
* getFolderName("/home/admin/a.txt/b.mp") = "/home/admin/a.txt"
* </pre>
*
* @param filePath
* @return
*/
public static String getFolderName(String filePath) {
if (StringUtils.isEmpty(filePath)) {
return filePath;
}
int filePosi = filePath.lastIndexOf(File.separator);
return (filePosi == -) ? "" : filePath.substring(, filePosi);
}
/**
* get suffix of file from path
*
* <pre>
* getFileExtension(null) = ""
* getFileExtension("") = ""
* getFileExtension(" ") = " "
* getFileExtension("a.mp") = "mp"
* getFileExtension("a.b.rmvb") = "rmvb"
* getFileExtension("abc") = ""
* getFileExtension("c:\\") = ""
* getFileExtension("c:\\a") = ""
* getFileExtension("c:\\a.b") = "b"
* getFileExtension("c:a.txt\\a") = ""
* getFileExtension("/home/admin") = ""
* getFileExtension("/home/admin/a.txt/b") = ""
* getFileExtension("/home/admin/a.txt/b.mp") = "mp"
* </pre>
*
* @param filePath
* @return
*/
public static String getFileExtension(String filePath) {
if (StringUtils.isBlank(filePath)) {
return filePath;
}
int extenPosi = filePath.lastIndexOf(FILE_EXTENSION_SEPARATOR);
int filePosi = filePath.lastIndexOf(File.separator);
if (extenPosi == -) {
return "";
}
return (filePosi >= extenPosi) ? "" : filePath.substring(extenPosi + );
}
/**
* Creates the directory named by the trailing filename of this file, including the complete directory path required
* to create this directory. <br/>
* <br/>
* <ul>
* <strong>Attentions:</strong>
* <li>makeDirs("C:\\Users\\Trinea") can only create users folder</li>
* <li>makeFolder("C:\\Users\\Trinea\\") can create Trinea folder</li>
* </ul>
*
* @param filePath
* @return true if the necessary directories have been created or the target directory already exists, false one of
* the directories can not be created.
* <ul>
* <li>if {@link FileUtils#getFolderName(String)} return null, return false</li>
* <li>if target directory already exists, return true</li>
* <li>return {@link java.io.File#makeFolder}</li>
* </ul>
*/
public static boolean makeDirs(String filePath) {
String folderName = getFolderName(filePath);
if (StringUtils.isEmpty(folderName)) {
return false;
}
File folder = new File(folderName);
return (folder.exists() && folder.isDirectory()) ? true : folder.mkdirs();
}
/**
* @param filePath
* @return
* @see #makeDirs(String)
*/
public static boolean makeFolders(String filePath) {
return makeDirs(filePath);
}
/**
* Indicates if this file represents a file on the underlying file system.
*
* @param filePath
* @return
*/
public static boolean isFileExist(String filePath) {
if (StringUtils.isBlank(filePath)) {
return false;
}
File file = new File(filePath);
return (file.exists() && file.isFile());
}
/**
* Indicates if this file represents a directory on the underlying file system.
*
* @param directoryPath
* @return
*/
public static boolean isFolderExist(String directoryPath) {
if (StringUtils.isBlank(directoryPath)) {
return false;
}
File dire = new File(directoryPath);
return (dire.exists() && dire.isDirectory());
}
/**
* delete file or directory
* <ul>
* <li>if path is null or empty, return true</li>
* <li>if path not exist, return true</li>
* <li>if path exist, delete recursion. return true</li>
* <ul>
*
* @param path
* @return
*/
public static boolean deleteFile(String path) {
if (StringUtils.isBlank(path)) {
return true;
}
File file = new File(path);
if (!file.exists()) {
return true;
}
if (file.isFile()) {
return file.delete();
}
if (!file.isDirectory()) {
return false;
}
for (File f : file.listFiles()) {
if (f.isFile()) {
f.delete();
} else if (f.isDirectory()) {
deleteFile(f.getAbsolutePath());
}
}
return file.delete();
}
/**
* get file size
* <ul>
* <li>if path is null or empty, return -</li>
* <li>if path exist and it is a file, return file size, else return -</li>
* <ul>
*
* @param path
* @return returns the length of this file in bytes. returns - if the file does not exist.
*/
public static long getFileSize(String path) {
if (StringUtils.isBlank(path)) {
return -;
}
File file = new File(path);
return (file.exists() && file.isFile() ? file.length() : -);
}
}
十三、assets和raw资源工具类 ResourceUtils.java
public class ResourceUtils {
private ResourceUtils() {
throw new AssertionError();
}
/**
* get an asset using ACCESS_STREAMING mode. This provides access to files that have been bundled with an
* application as assets -- that is, files placed in to the "assets" directory.
*
* @param context
* @param fileName The name of the asset to open. This name can be hierarchical.
* @return
*/
public static String geFileFromAssets(Context context, String fileName) {
if (context == null || StringUtils.isEmpty(fileName)) {
return null;
}
StringBuilder s = new StringBuilder("");
try {
InputStreamReader in = new InputStreamReader(context.getResources().getAssets().open(fileName));
BufferedReader br = new BufferedReader(in);
String line;
while ((line = br.readLine()) != null) {
s.append(line);
}
return s.toString();
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
/**
* get content from a raw resource. This can only be used with resources whose value is the name of an asset files
* -- that is, it can be used to open drawable, sound, and raw resources; it will fail on string and color
* resources.
*
* @param context
* @param resId The resource identifier to open, as generated by the appt tool.
* @return
*/
public static String geFileFromRaw(Context context, int resId) {
if (context == null) {
return null;
}
StringBuilder s = new StringBuilder();
try {
InputStreamReader in = new InputStreamReader(context.getResources().openRawResource(resId));
BufferedReader br = new BufferedReader(in);
String line;
while ((line = br.readLine()) != null) {
s.append(line);
}
return s.toString();
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
/**
* same to {@link ResourceUtils#geFileFromAssets(Context, String)}, but return type is List<String>
*
* @param context
* @param fileName
* @return
*/
public static List<String> geFileToListFromAssets(Context context, String fileName) {
if (context == null || StringUtils.isEmpty(fileName)) {
return null;
}
List<String> fileContent = new ArrayList<String>();
try {
InputStreamReader in = new InputStreamReader(context.getResources().getAssets().open(fileName));
BufferedReader br = new BufferedReader(in);
String line;
while ((line = br.readLine()) != null) {
fileContent.add(line);
}
br.close();
return fileContent;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
/**
* same to {@link ResourceUtils#geFileFromRaw(Context, int)}, but return type is List<String>
*
* @param context
* @param resId
* @return
*/
public static List<String> geFileToListFromRaw(Context context, int resId) {
if (context == null) {
return null;
}
List<String> fileContent = new ArrayList<String>();
BufferedReader reader = null;
try {
InputStreamReader in = new InputStreamReader(context.getResources().openRawResource(resId));
reader = new BufferedReader(in);
String line = null;
while ((line = reader.readLine()) != null) {
fileContent.add(line);
}
reader.close();
return fileContent;
} catch (IOException e) {
e.printStackTrace();
return null;
}
}
}
十四、单例工具类 SingletonUtils.java
public abstract class SingletonUtils<T> {
private T instance;
protected abstract T newInstance();
public final T getInstance() {
if (instance == null) {
synchronized (SingletonUtils.class) {
if (instance == null) {
instance = newInstance();
}
}
}
return instance;
}
}
十五、数据库工具类 SqliteUtils.java
public class SqliteUtils {
private static volatile SqliteUtils instance;
private DbHelper dbHelper;
private SQLiteDatabase db;
private SqliteUtils(Context context) {
dbHelper = new DbHelper(context);
db = dbHelper.getWritableDatabase();
}
public static SqliteUtils getInstance(Context context) {
if (instance == null) {
synchronized (SqliteUtils.class) {
if (instance == null) {
instance = new SqliteUtils(context);
}
}
}
return instance;
}
public SQLiteDatabase getDb() {
return db;
}
}
标签：SQLite
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数据库系统概念 第6版
本书主要讲述了数据模型、基于对象的数据库和XML、数据存储和查询、事务管理、体系结构等方面的内容。
