Java 基础查漏补缺【IO篇】

//读取一个字节并以证书的形式返回（0～255）
//如果返回为-1表示输入流已经到末尾了
int read() throws IoException 

//读取一系列字节并存储到一个数据buffer
 //返回实际读取的字节数，如果读取前已经到输入流的末尾返回-1   
  //即将字节数据都先放在内存的缓冲区buffer中，然后统一处理
  int read(byte[] buffer) throw IoException
  
  //读取length个字节
  //并存储到一个字节数组buffer，从length位置开始
  //返回实际读取的字节数，如果读取前已经到输入流的末尾返回-1
  int read(byte[] buffer,int offset，int length) throws IOException
  
  //关闭流释放内存资源
  void close() throw IOException
  
  //跳过N个字节不读，返回实际跳过的字节数
  long skip(long n) throws IOException

//向输出流中写入一个字节数据，该字节数据为参数b的低8位
//这个方法会写入一个字节到输出流。要注意的是，虽然传入的是int参数，但只会写入一个字节，即只写入int最低8位表示字节的部分（相当于b & 0xff）。
void write(int b)throws IOException
  
//将一个字节类型的数组中的数据写入输出流
  void write(byte[] b)throws IOException
 
 //将一个字节类型的数组中的从指定位置off开始的len个字节写入到输出流
 void write(byte[] b,int off,int len) throws IOException

//关闭流释放内存资源
 void close() throws IOException
  
//将输出流中缓冲的数据全部写出到目的地
 void flush()throws IOEXception

//将一个字符串中的字符写入到输出流
void write(String string)throws IOException

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

public class TestFileInputStream {
    public static void main(String[] args) {
        int b = 0;
        FileInputStream in = null;
        try {
            in = new FileInputStream("/Users/Steven/GitRepositories/scaffold/src/main/java/com/shifpeng/scaffold/test/TestFileInputStream.java");
        } catch (FileNotFoundException e) {
            System.out.printf("找不到指定文件");
        }

        try {
            long num = 0;
            while ((b = in.read()) != -1) {
                System.out.printf((char) b + "");
                num++;
            }
            in.close();
            System.out.printf("一共读到了" + num + "个字节");
        } catch (IOException e) {
            e.printStackTrace();
            System.out.printf("文件读取失败");
        }
    }
}

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class TestFileOutputStream {
    public static void main(String[] args) {
        int b = 0;
        FileInputStream in = null;
        FileOutputStream out = null;
        try {
            in = new FileInputStream("/Users/Steven/GitRepositories/scaffold/src/main/java/com/shifpeng/scaffold/test/TestFileInputStream.java");
            out = new FileOutputStream("/Users/Steven/GitRepositories/scaffold/src/main/java/com/shifpeng/scaffold/test/TestFileInputStream_bak.java");
            while ((b = in.read()) != -1) {
                out.write(b);
            }
            in.close();
            out.close();
        } catch (FileNotFoundException e) {
            System.out.printf("找不到指定文件");
        } catch (IOException e) {

        }
        System.out.printf("文件赋值成功");
    }
}

BufferedReader(Reader in);
BufferedReader(Reader in，int sz); //sz 为自定义缓冲区的大小
BufferedWriter(Writer out);
BufferedWriter(Writer out，int sz);
BufferedInputStream(InputStream in);
BufferedInputStream(InputStream in,int sz);
BufferedOutputStream(OutputStream out)
BufferedOutputStream(OutputStream out，int sz)

public static void main(String[] args) {
    try {
        FileInputStream in = new FileInputStream("/Users/Steven/GitRepositories/scaffold/src/main/java/com/shifpeng/scaffold/test/TestFileInputStream.java");
        BufferedInputStream bufferedInputStream = new BufferedInputStream(in);
        bufferedInputStream.mark(100);
        int c = 0;
        for (int i = 0; i <= 10 && (c = bufferedInputStream.read()) != -1; i++) {
            System.out.printf((char) c + " ");
        }
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    } catch (IOException e) {

    }
}

try {
            //写文件
            OutputStreamWriter osw = new OutputStreamWriter(new FileOutputStream(""));
            //读文件
            InputStreamReader isr = new InputStreamReader(new FileInputStream(""));
            //键盘的输入
            InputStreamReader isr1 = new InputStreamReader(System.in);
            //这里再转一下，是因为BufferedReader有个很好用的方法，可以一次读取一行
            BufferedReader bw=new BufferedReader(isr1);
            bw.readLine();

        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }