File读写复制

Posted 2021-09-06 Recently 祝祝

1：读:从外部把数据读到内存中，input，write

package com.uplooking.io;

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

public class BufferWriterTest {
	private String path;
	private String name;

	public BufferWriterTest(String path, String name) {
		super();
		this.path = path;
		this.name = name;
	}

	private void mkdir() {
		File file = new File(path);
		if (!file.exists()) {
			file.mkdirs();
		}
	}

	public void bufferwrite() {
		mkdir();
		File file = new File(path + "/" + name);
		FileWriter fileWriter = null;
		BufferedWriter bufferedWriter = null;
		try {
			fileWriter = new FileWriter(file);
			bufferedWriter = new BufferedWriter(fileWriter);
			bufferedWriter.write("hello shimmer");
			bufferedWriter.flush();
			System.err.println("数据读入成功，文件位置位于：" + file.getAbsolutePath());
		} catch (Exception e) {

			e.printStackTrace();
		} finally {
			try {
				if (bufferedWriter != null)
					bufferedWriter.close();
				if (fileWriter != null)
					fileWriter.close();
			} catch (IOException e1) {
				e1.printStackTrace();
			}
		}

	}
	public static void main(String[] args) {
		BufferWriterTest  bfWriter= new BufferWriterTest("H:\\\\0812", "code3.txt");
		bfWriter.bufferwrite();
	}
}

2：写：把数据从内存写到外部，output，reader

package com.uplooking.io;

import java.io.File;
import java.io.FileReader;

public class ReaderTest {
	private String path;
	private String name;

	public ReaderTest(String path, String name) {
		super();
		this.path = path;
		this.name = name;
	}

	public void reader() {
		File file = new File(path + "/" + name);
		FileReader fr = null;

		try {
			fr = new FileReader(file);
			char[] chs = new char[10];
			int len = fr.read(chs); // 把数据向chs数组中填充，
			while (len != -1) {
				System.out.println("本次读到的有效个数是：" + len);
				String string = new String(chs, 0, len); // 构造成字符串
				System.out.println("本次读到的内容：" + string);
				len = fr.read(chs);
			}
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			try {
				if (fr != null) {
					fr.close();
				}
			} catch (Exception e) {
				e.printStackTrace();
			}
		}

	}

	public static void main(String[] args) {
		ReaderTest r1 = new ReaderTest("H:\\\\0812", "code1.txt");
		r1.reader();
	}

}

3：边写边读

package com.uplooking.io;

import java.io.File;
import java.io.FileReader;
import java.io.FileWriter;

public class ReaderWriter2 {
	private String path;
	private String name;

	public ReaderWriter2(String path, String name) {
		super();
		this.path = path;
		this.name = name;
	}

	public void read() {
		File file = new File( path +"/"+name );
		FileReader fReader =null;
		FileWriter fWriter = null;
		File Outfile = new File(path + "/"+"new"+name);
		
		try {
			fWriter =new  FileWriter(Outfile);
			fReader = new FileReader(file);
			char[] chs =new char[10];
			int len =fReader.read(chs); // 把数据向数组中填充，填了多少个由len记录
			
			while ( len != -1 ) {
				System.err.println("本次读到的有效个数 = " + len );
				String s  = new String(chs,0,len);
				System.out.println("本次读到的数据:"+s);
				fWriter.write(chs , 0 , len );
				len = fReader.read(chs);
			}
			fWriter.flush();
		} catch (Exception e) {
			e.printStackTrace();
		} finally {
			try {
				if (null != fReader) {
					fReader.close();
				}
				if (null != fWriter) {
					fWriter.close();
				}
			} catch ( Exception e) {
				e.printStackTrace();
			}
		}
	}
	public static void main(String[] args) {
		ReaderWriter2 rdw = new ReaderWriter2("H://0812", "code1.txt");
		rdw.read();
	}
}

4：复制文件

package com.uplooking.io;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;

public class CopyFileTest {
	private String path;
	private String name;

	public CopyFileTest(String path, String name) {
		super();
		this.path = path;
		this.name = name;
	}

	public void copy() {
		File inFile = new File(path + "/" + name);
		File outFile = new File(path + "/new" + name);

		FileInputStream fileInputStream = null;
		FileOutputStream fileOutputStream = null;

		try {
			fileInputStream = new FileInputStream(inFile);
			fileOutputStream = new FileOutputStream(outFile);

			byte[] bs = new byte[1024];
			int len = fileInputStream.read(bs);

			while (-1 != len) {
				fileOutputStream.write(bs, 0, len);
				len = fileInputStream.read(bs);
			}
			fileOutputStream.flush();
			System.out.println(outFile + "复制完成");
		} catch (Exception e) {
			e.printStackTrace();
			System.err.println(outFile + "复制失败");
		} finally {
			try {
				if (fileInputStream != null) {
					fileInputStream.close();
				}
				if (fileOutputStream != null) {
					fileOutputStream.close();
				}
			} catch (Exception e2) {
				e2.printStackTrace();
			}
		}
	}
public static void main(String[] args) {
	CopyFileTest copyFileTest = new CopyFileTest("H://0812", "code3.txt");
	copyFileTest.copy();
}
}

end》》》
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