java十六（字符和字节的输入和输出）

* 没有用文本就用字节

* 用到文本就要字符

一、字节的写入和读取

package File类;

import java.io.*;

public class 文件写入和读取 {
    public static void main(String[] args) {

        File file = new File("./1.js");
        // writeFile(file, "欧富华");
        // appendFileContent(file, "欧富华");
        getFileContent(file);

    }

    // 写入文件就是输出流
    public static void writeFile(File file, String content) {
        // 写入就是输出流
        try {
            FileOutputStream out = new FileOutputStream(file);
            out.write(content.getBytes());
            System.out.println("写入成功");
            out.close(); // 关闭流
        } catch (Exception e) {
        }
    }

    // 文件追加内容
    public static void appendFileContent(File file, String content) {
        // 写入就是输出流
        try {
            FileOutputStream out = new FileOutputStream(file, true);
            out.write(content.getBytes());
            System.out.println("追加写入成功");
            out.close(); // 关闭流
        } catch (Exception e) {
        }
    }

    // 文件读取就是输入流
    public static void getFileContent(File file) {
        try {
            int len = 0;
            StringBuilder stringBuilder = new StringBuilder();

            byte[] bytes = new byte[1024]; // 定义读取数量

            FileInputStream fileInputStream = new FileInputStream(file);

            // 不等于-1就是存在字节
            while ((len=fileInputStream.read(bytes)) != -1) {
                System.out.println((char)len);
                System.out.println(11111);
                stringBuilder.append(new String(bytes), 0, 7);
            }

            fileInputStream.close(); // 关闭流

            System.out.println(stringBuilder);

            fileInputStream.close();

        } catch (Exception e) {
        }

    }
}

二、字符写入和读取

package File类;

import java.io.*;

public class 字符write和read {
    public static void main(String[] args) {
        File file = new File("1.js");
        wirte(file);
        read(file);
    }

    public static void wirte(File file) {
        try {

            Writer writer = new FileWriter(file, true);
            writer.write("我叫欧富华");
            writer.close();

        } catch (Exception e) {

        }
    }

    public static void read(File file) {
        try {

            Reader reader = new FileReader(file);
            char[] c = new char[1]; // 一个字符
            StringBuilder stringBuilder = new StringBuilder();

            while ((reader.read(c)) != -1) {
                stringBuilder.append(new String(c));
            }

            reader.close();

            System.out.println(stringBuilder);

        } catch (Exception e) {

        }

    }
}

三、案例（文件的复制）

package File类;

import java.io.*;

public class copyDemo {
    public static void main(String[] args) {
        copyBytes("1.js", "copy.js");
        copyChars("1.js", "copy1.js");
        System.out.println("复制成功");
    }

    // 字节的复制
    static void copyBytes(String src, String targer) {
        FileInputStream fileInputStream = null;
        FileOutputStream fileOutputStream = null;
        try {
            File srcFile = new File(src);
            File targerFile = new File(targer);

            fileInputStream = new FileInputStream(srcFile);  // 读取
            fileOutputStream = new FileOutputStream(targerFile); // 写入

            byte[] bytes = new byte[1024];
            int len = -1;
            while ((len = fileInputStream.read(bytes)) != -1) {
                fileOutputStream.write(bytes, 0, len);
            }

        } catch (Exception e) {

        } finally {
            try {
                if (fileInputStream != null) fileInputStream.close();
                if (fileOutputStream != null) fileOutputStream.close();
            } catch (Exception e) {

            }

        }

    }

    public static void copyChars(String src, String targer) {
        Reader reader = null;
        Writer writer = null;
        try {
            File srcFile = new File(src);
            File targerFile = new File(targer);

            reader = new FileReader(srcFile);
            writer = new FileWriter(targerFile);
            int len = -1;
            char[] chars = new char[1];
            while ((len = reader.read(chars)) != -1) {
                writer.write(chars, 0, len);
            }

        } catch (Exception e) {

        } finally {
            try {
                if (writer != null) writer.close();
                if (reader != null) reader.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}