I/O流的设计模式，分类，抽象类还有常用流

总结1345

即一个设计模式，3种分类，4个抽象类，5个处理流。文章有点长，有需要自行ctrl+f搜索自己需要的内容即可。

一个设计模式——装饰器模式

装饰者模式允许在不改变现有类的基础上增加新的功能。在I/O流中，装饰者模式通过层层包装原始流，比如使用BufferedInputStream包装FileInputStream，可以在读取操作中加入缓冲机制，而无需修改FileInputStream的原有代码。

3个分类

按照流向分为：输入流和输出流
按照数据单位分为：字节流和字符流
按照功能分为：节点流和处理流

输入流和输出流

import java.io.FileInputStream;
import java.io.IOException;
public class InputFile {public static void main(String[] args) {try{FileInputStream file = new FileInputStream("C:\\Users\\book.txt");int data;while ((data = file.read()) != -1)System.out.print((char) data);} catch (IOException e){System.out.println(e);}}
}import java.io.FileOutputStream;
import java.io.IOException;
public class OutputFile {public static void main(String[] args) {try{FileOutputStream file = new FileOutputStream("C:\\Users\\book.txt");String text = "test";byte[] bytes = text.getBytes();file.write(bytes);} catch (IOException e){System.out.println(e);}}
}

字节流和字符流

import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;public class FileRW {public static void main(String[] args) {try{FileReader reader = new FileReader("C:\\Users\\book.txt");int data;while ((data = reader.read())!=-1){System.out.print((char) data);}} catch (IOException e){System.out.println(e);}try(FileWriter writer = new FileWriter("C:\\Users\\book.txt")){String text = "test success";writer.write(text);} catch (IOException e){System.out.println(e);}}
}

节点流和处理流

public class FileFB {public static void main(String[] args) {try (FileInputStream fileInputStream = new FileInputStream("C:\\Users\\book.txt");BufferedInputStream bufferedInputStream = new BufferedInputStream(fileInputStream);FileOutputStream fileOutputStream = new FileOutputStream("C:\\Users\\book.txt");BufferedOutputStream bufferedOutputStream = new BufferedOutputStream(fileOutputStream)) {int data;while ((data = bufferedInputStream.read()) != -1) {bufferedOutputStream.write(data);}bufferedOutputStream.flush();} catch (IOException e) {e.printStackTrace();}}
}

四个抽象类

InputStream：所有字节输入流的基类。
OutputStream：所有字节输出流的基类。
Reader：所有字符输入流的基类。
Writer：所有字符输出流的基类。

InputStream

import java.io.FileInputStream;
import java.io.IOException;
public class InputFile {public static void main(String[] args) {try{FileInputStream file = new FileInputStream("C:\\Users\\book.txt");int data;while ((data = file.read()) != -1)System.out.print((char) data);} catch (IOException e){System.out.println(e);}}
}

OutputStream

import java.io.FileOutputStream;
import java.io.IOException;
public class OutputFile {public static void main(String[] args) {try{FileOutputStream file = new FileOutputStream("C:\\Users\\book.txt");String text = "test";byte[] bytes = text.getBytes();file.write(bytes);} catch (IOException e){System.out.println(e);}}
}

Reader（方法）

try{FileReader reader = new FileReader("C:\\Users\\book.txt");
int data;while ((data = reader.read())!=-1){System.out.print((char) data);}} catch (IOException e){System.out.println(e);
}

Writer（方法）

try(FileWriter writer = new FileWriter("C:\\Users\\book.txt")){String text = "test success";writer.write(text);
} catch (IOException e){System.out.println(e);}
}