Java学习第六课 JAVA 文件操作

平常经常使用JAVA对文件进行读写等操作，这里汇总一下常用的文件操作。

1、创建文件

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public static boolean createFile(String filePath){

boolean result = false;

File file = new File(filePath);

if(!file.exists()){

try {

result = file.createNewFile();

} catch (IOException e) {

e.printStackTrace();

}

}

return result;

}

2、创建文件夹

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public static boolean createDirectory(String directory){

boolean result = false;

File file = new File(directory);

if(!file.exists()){

result = file.mkdirs();

}

return result;

}

3、删除文件

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public static boolean deleteFile(String filePath){

boolean result = false;

File file = new File(filePath);

if(file.exists() && file.isFile()){

result = file.delete();

}

return result;

}

4、删除文件夹

递归删除文件夹下面的子文件和文件夹

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public static void deleteDirectory(String filePath){

File file = new File(filePath);

if(!file.exists()){

return;

}

if(file.isFile()){

file.delete();

}else if(file.isDirectory()){

File[] files = file.listFiles();

for (File myfile : files) {

deleteDirectory(filePath + "/" + myfile.getName());

}

file.delete();

}

}

5、读文件

（1）以字节为单位读取文件，常用于读二进制文件，如图片、声音、影像等文件

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public static String readFileByBytes(String filePath){

File file = new File(filePath);

if(!file.exists() || !file.isFile()){

return null;

}

StringBuffer content = new StringBuffer();

try {

byte[] temp = new byte[1024];

FileInputStream fileInputStream = new FileInputStream(file);

while(fileInputStream.read(temp) != -1){

content.append(new String(temp));

temp = new byte[1024];

}

fileInputStream.close();

} catch (FileNotFoundException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}

return content.toString();

}

（2）以字符为单位读取文件，常用于读文本，数字等类型的文件，支持读取中文

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public static String readFileByChars(String filePath){

File file = new File(filePath);

if(!file.exists() || !file.isFile()){

return null;

}

StringBuffer content = new StringBuffer();

try {

char[] temp = new char[1024];

FileInputStream fileInputStream = new FileInputStream(file);

InputStreamReader inputStreamReader = new InputStreamReader(fileInputStream, "GBK");

while(inputStreamReader.read(temp) != -1){

content.append(new String(temp));

temp = new char[1024];

}

fileInputStream.close();

inputStreamReader.close();

} catch (FileNotFoundException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}

return content.toString();

}

（3）以行为单位读取文件，常用于读面向行的格式化文件

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public static List<String> readFileByLines(String filePath){

File file = new File(filePath);

if(!file.exists() || !file.isFile()){

return null;

}

List<String> content = new ArrayList<String>();

try {

FileInputStream fileInputStream = new FileInputStream(file);

InputStreamReader inputStreamReader = new InputStreamReader(fileInputStream, "GBK");

BufferedReader reader = new BufferedReader(inputStreamReader);

String lineContent = "";

while ((lineContent = reader.readLine()) != null) {

content.add(lineContent);

System.out.println(lineContent);

}

fileInputStream.close();

inputStreamReader.close();

reader.close();

} catch (FileNotFoundException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

}

return content;

}

6、写文件

字符串写入文件的几个类中，FileWriter效率最高，BufferedOutputStream次之，FileOutputStream最差。

（1）通过FileOutputStream写入文件

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public static void writeFileByFileOutputStream(String filePath, String content) throws IOException{

File file = new File(filePath);

synchronized (file) {

FileOutputStream fos = new FileOutputStream(filePath);

fos.write(content.getBytes("GBK"));

fos.close();

}

}

（2）通过BufferedOutputStream写入文件

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public static void writeFileByBufferedOutputStream(String filePath, String content) throws IOException{

File file = new File(filePath);

synchronized (file) {

BufferedOutputStream fos = new BufferedOutputStream(new FileOutputStream(filePath));

fos.write(content.getBytes("GBK"));

fos.flush();

fos.close();

}

}

（3）通过FileWriter将字符串写入文件

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public static void writeFileByFileWriter(String filePath, String content) throws IOException{

File file = new File(filePath);

synchronized (file) {

FileWriter fw = new FileWriter(filePath);

fw.write(content);

fw.close();

}

}

本文转载自：/article/11374448.html