字节流demo

字节输出流,输出到对应的文件中

public class FileOutputStreamDemo {
    public static void main(String[] args) throws Exception {
        //1.创建目标对象
        File target  = new File("H:/xinyi/stream/OutputStrean.txt");
        //2.创建字节输出流对象
        OutputStream out = new FileOutputStream(target);
        //3.具体操作
        out.write("HelloKitty".getBytes(),5, 5);
        //关闭流
        out.close();
    }
}

---

字节输入流:

public class FileInputStreamDemo {
    public static void main(String[] args) throws Exception {
        //1.创建源
        File resources  = new File("H:/xinyi/stream/OutputStrean.txt");
        //2.创建字节输入流，并连接源
        InputStream in = new FileInputStream(resources);
        //3.具体的读取操作
        byte[] buffer = new byte[5];
        int len = -1;
        //in.read(buffer)  读取多个字节，并且存储到buffer数组中，返回读取字节的个数
        while ((len = in.read(buffer)) != -1) {
            String str = new String(buffer, 0,len);
            System.out.println(str);
        }
        //4.关闭流
        in.close();
    }
}

---

public class StreamCopyDemo {
    public static void main(String[] args){
        //1.创建源（输入）
        File resources  = new File("H:/xinyi/stream/OutputStrean.txt");
        //1.创建目标（输出）
        File target  = new File("H:/xinyi/stream/OutputStrean_target.txt");
        try(
            //2.创建输入流对象
            InputStream in = new FileInputStream(resources);
            //2.创建输出流对象
            OutputStream out = new FileOutputStream(target);
            ){
            //3.具体io操作
            byte [] buffer = new byte[25];
            int len = -1; 
            //in.read(buffer)  读取多个字节，并且存储到buffer数组中,返回读取字节的个数;如果是-1,说明文件已读完
            while ((len = in.read(buffer))!= -1) {
                out.write(buffer, 0, len);
            }
        }catch (Exception e) {
            e.printStackTrace();
        }
    }
}

---

字符编码转换:

public class EnCodingDemo {
    public static void main(String[] args) throws Exception {
        String msg = "生活不止眼前的苟且";
        byte[] data = msg.getBytes("UTF-8");
        String ret = new String(data,"ISO-8859-1");
        data = ret.getBytes("ISO-8859-1");
        ret = new String(data,"UTF-8");
        System.out.println(ret);
    }
}