java写文件的基本操作

Posted 2020-06-14

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;

public class FileIO {

	/**
	 * @param args
	 * @throws IOException
	 */
	public static void main(String[] args) throws IOException {

		// 1.创建文件夹 mkdir
		// 如果路径存在，才可以通过该方法创建文件夹。。。mkdirs路径不存在也可以通过这个方法创建，先创建路径再创建文件夹
		File myFolderPath = new File("D:\\MyEclipse2013Work\\Test\\test");
		try {
			if (!myFolderPath.exists()) {
				myFolderPath.mkdir();
			}
		} catch (Exception e) {
			System.out.println("新建目录操作出错");
			e.printStackTrace();
		}

		// 2. 创建文件 FileWrite 和PrintWrite 的区别需要注意
		File myFilePathFile = new File("test.txt");
		try {
			if (!myFilePathFile.exists()) {
				myFilePathFile.createNewFile();
			}
			FileWriter resultFile = new FileWriter(myFilePathFile);
			PrintWriter myFile = new PrintWriter(resultFile);
			myFile.println("新建文件操作");
			myFile.println("新建文件操作");
			myFile.println("新建文件操作");
			myFile.println("新建文件操作");
			myFile.write("sss", 1, 1);
			myFile.println("新建文件操作");
			resultFile.write("sssssssssssss");
			resultFile.close();
		} catch (Exception e) {
			// TODO: handle exception
			System.out.println("新建文件操作出错");
			e.printStackTrace();
		}

		// 3. FileWrite 结合BufferedWriter打印文本换行
		TestBufferedWriter();

		// 4.获得当前工程的路径
		File directory = new File("");// 参数为空
		String courseFile = directory.getCanonicalPath();
		System.out.println(courseFile);
	}

	public static void TestBufferedWriter() {
		try {

			String filePath = "test1.txt";
			File myFile = new File(filePath);
			if (!myFile.exists()) {
				myFile.createNewFile();
			}
			FileWriter resultFile = new FileWriter(myFile);
			BufferedWriter buffer = new BufferedWriter(resultFile);
			String fileContent = "This is my name./n we are isoftsotne.com /n chinesebillboy at here。/n";
			String contentString = "";
			int flag = 0;
			boolean isGO = true;
			while ((flag = fileContent.indexOf("/n")) != -1 && isGO) {
				contentString = fileContent.substring(0, flag);
				buffer.write(contentString);
				buffer.newLine();
				buffer.flush();
				if (flag + 2 >= fileContent.length()) {
					isGO = false;
				} else {
					fileContent = fileContent.substring(flag + 2);
				}
			}
			buffer.flush();
			resultFile.flush();
			buffer.close();
			resultFile.close();
		} catch (IOException ioe) {
			ioe.printStackTrace();
		} finally {

		}
	}
}