new File(String pathName)//根据路径构建一个File对象
new File(File parent, String child)//根据父目录文件 + 子路径构建
new File(String parent, String child)//根据父目录 + 子路径创建
createNewFile //创建新文件

//方式一 newFile(String)
    @Test
    public void create01() throws IOException {
        String filePath = "j:\\news1.txt";
        File file = new File(filePath);

        file.createNewFile();
        System.out.println("文件创建成功...");
    }

    //方式二 new File(File parent, String child)
    //根据父目录文件 + 子路径构建
    //j:\\news2.txt
    @Test
    public void create02() {
        File patentFile = new File("j:\\");
        String fileName = "news2.txt";
        File file = new File(patentFile, fileName);

        //创建文件
        try {
            file.createNewFile();
            System.out.println("创建成功...");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Test
    //方式三 new File(String parent, String child)
    //根据父目录+子路径构建
    public void create03() {
        String parentPath = "j:\\";
        String fileName = "news3.txt";
        File file = new File(parentPath, fileName);

        try {
            file.createNewFile();
            System.out.println("文件创建...");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

@Test
    //获取文件信息
    public void info() {
        //先创建文件
        File file = new File("j:\\news1.txt");
        //调用相应的方法，得到对应信息
        System.out.println("文件名字= " + file.getName());
        System.out.println("文件绝对路径= " + file.getAbsolutePath());
        System.out.println("文件父级目录= " + file.getParent());
        System.out.println("文件大小(字节)= " + file.length());
        System.out.println("文件是否存在= " + file.exists());
        System.out.println("是不是一个文件= " + file.isFile());
        System.out.println("是不是一个目录= " + file.isDirectory());
    }

@Test
    public void writeFile() {
        //创建 FileOutputStream对象
        String filePath = "j:\\a.txt";
        FileOutputStream fileOutputStream = null;
        try {
            //1. new FileOutputStream(filePath) 创建方式, 当写入内容时, 会覆盖原来的内容
            //2. new FileOutputStream(filePath, true) 创建方式, 写入内容时, 是最佳到文件后面
            fileOutputStream = new FileOutputStream(filePath, true);
            //写入一个字符
            //fileOutputStream.write('H');
            //写入一个字符串
            String str = "hello,world!";
            String str1 = "执笔";
            //str.getBytes() 可以把字符串转成字节数组
            //fileOutputStream.write(str.getBytes());
            //write(byte[] b, int off, int len) 将len字节从位于偏移量off的指定字节数组
            //第二种
            fileOutputStream.write(str.getBytes(), 0, str.length());
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                fileOutputStream.close();//流关闭
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

public class BufferedCopy_ {
    public static void main(String[] args) throws IOException {
        String srcFilePath = "j:\\story.txt";//文件路径
        String destFilePath = "e:\\story.txt";//拷贝后路径
        //1. BufferedReader 和 BufferedWriter 字符操作
        //2. 不要去操作二进制文件 [声音、视频、doc、pdf]，可能造成文件损坏
        BufferedReader bufferedReader = new BufferedReader(new FileReader(srcFilePath));
        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(destFilePath));
        String line;//按行读取
        while((line = bufferedReader.readLine()) != null) {
            //一边读一边写
            bufferedWriter.write(line);
            bufferedWriter.newLine();//换行
        }
        System.out.println("拷贝完毕...");
        /**
         * 使用try/catch/finally 捕获异常和 直接throws的区别
         * 前置无论是够异常finally一定会执行
         * 或者如果发生异常就不会执行
         */
        //关闭处理流
        //先判断再关闭 防止异常 NullPointerException
        if (bufferedReader != null) {
            bufferedReader.close();
        }
        if (bufferedWriter != null) {
            bufferedWriter.close();
        }
    }
}

public class BufferedCopy02 {
    public static void main(String[] args) {
        String srcFilePath = "e:\\ct.png";
        String destFilePath = "j:\\ct.png";
        BufferedInputStream bufferedInputStream = null;
        BufferedOutputStream bufferedOutputStream = null;
        byte[] buf = new byte[1024];//数组读取形式
        int len = 0;
        try {
            bufferedInputStream = new BufferedInputStream(new FileInputStream(srcFilePath));
            bufferedOutputStream = new BufferedOutputStream(new FileOutputStream(destFilePath));
            //拷贝
            while ((len = bufferedInputStream.read(buf)) != -1) {
                bufferedOutputStream.write(buf, 0, len);
            }
            System.out.println("拷贝完毕....");
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                //关闭流
                if(bufferedInputStream != null){
                    bufferedInputStream.close();
                }
                if (bufferedOutputStream != null) {
                    bufferedOutputStream.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

    }
}

public class InputAndOutput {
    public static void main(String[] args) {
        // System 类的public final static InputStream in = null;
        // System.in 的编译类型是InputStream
        // System.in 的运行类型是 BufferedInputStream
        // 表示的是标准输入 键盘
        System.out.println(System.in.getClass());
        // public final static PrintStream out = null;
        // System.out 编译类型是 PrintStream
        // System.out 运行类型是 PrintStream
        // 标准输出 显示器
        System.out.println(System.out);
        System.out.println("执笔...");
        Scanner scanner = new Scanner(System.in);
        System.out.println("请输入...");
        String next = scanner.next();
        System.out.println("next= " + next);
    }
}

public class InputStreamReader_ {
    public static void main(String[] args) throws IOException {
        String filePath = "j:\\a.txt";
        //1. 把FileInputStream 转成 InputStreamReader
        //2. 指定编码 gbk
        //InputStreamReader isr = new InputStreamReader(new FileInputStream(filePath), "gbk");
        //3. 把InputStreamReader 传入 BufferedReader
        //BufferedReader br = new BufferedReader(isr);
        //将2 和3 合在一起
        BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(filePath), "gbk"));
        // 4. 读取
        String s = br.readLine();
        System.out.println("读取内容：" + s);
        //5. 关闭外层流
        br.close();
    }
}

public class OutputStreamWriter_ {
    public static void main(String[] args) throws IOException {
        String filePath = "j:\\zb.txt";
        String charSet = "utf8";
        OutputStreamWriter osw = new OutputStreamWriter(new FileOutputStream(filePath), charSet);
        osw.write("您好，执笔...");
        osw.close();
        System.out.println("按照" + charSet + "编码 文件保存成功...");
    }
}

public class PrintStream_ {
    public static void main(String[] args) throws IOException {
        PrintStream out = System.out;
        //默认情况下PrintStream 输出数据的位置 标准输出 即显示器
        /*
            public void print(String s) {
                if (s == null) {
                    s = "null";
                }
                write(s);
            }
         */
        out.print("hello");
        //因为print 底层调用的是write 所以可以直接调用write进行打印/输出
        out.write("执笔，你好...".getBytes());
        out.close();
        //可以修改打印流输出的位置/设备
        // 输出修改到j:\f1.txt
        System.setOut(new PrintStream("j:\\f1.txt"));
        System.out.println("hello，执笔...");
    }
}

public class PrintWriter_ {
    public static void main(String[] args) throws IOException {
        PrintWriter printWriter = new PrintWriter(new FileWriter("j:\\test.txt"));
        printWriter.print("你好，北京...");
        //需要关闭流 不然不会刷新
        printWriter.close();//flush + 关闭流   这时才会将数据写入到文件
    }
}

load//加载配置文件的键值对到Properties对象list:将数据显示到指定设备
getProperty(key)//根据键获取值
setProperty(key,value)//设置键值对到Properties对象
store//将Properties中的键值对存储到配置文件,在idea中,保存信息到配置文件，如果含有中文，会存储为unicode码

public class Properties02 {
    public static void main(String[] args) throws IOException {
        //1. 创建Properties
        Properties properties = new Properties();
        //2. 加载配置文件
        properties.load(new FileReader("src\\mysql.properties"));
        //3. 把k-v显示在控制台
        properties.list(System.out);
        //4. 根据key 获取对应的值
        String user = properties.getProperty("user");
        String psw = properties.getProperty("psw");
        System.out.println("用户名：" + user);
        System.out.println("密码：" + psw);
    }
}

public class Properties03 {
    public static void main(String[] args) throws IOException {
        //1. 创建Properties 集合对象
        Properties pro = new Properties();
        //2. 向Properties中添加 键值对信息
        //1. 如果该文件没有key 就是添加
        //2. 如果有就是覆盖
        pro.setProperty("charset", "utf-8");
        pro.setProperty("port", "443");
        pro.setProperty("name", "北京");
        pro.setProperty("name", "执笔");
        //3. 储存到文件中 (pro ---> 文件)
        // 这里的null 指注释  一般情况下 写成null
        pro.store(new FileOutputStream("src\\mysql2.properties"), null);
        System.out.println("保存配置文件成功....");
    }
}