使用其他子类读取写入文本

使用PrintWriter写入读取文本

public static void main(String[] args) throws IOException {
        //写入文本
        String fileUrl = BaseWriteFile.getFileUrl("G:/java_test/git/jBase/build/resources/main/file4WriteData.txt");
        try (
                PrintWriter printWriter = new PrintWriter(new OutputStreamWriter(
                        new FileOutputStream(fileUrl, false), "UTF-8"
                ), true)) {
            printWriter.print("MyAge is ");
            printWriter.print(12);
            printWriter.println(" age.");
        }
        //读取文本输入
        Path path = Paths.get(fileUrl);
        if(path!=null) {
            String s = new String(Files.readAllBytes(path), "UTF-8");
            System.out.println(s);

            try(Stream<String> lines = Files.lines(path)){
               lines.forEach(System.out::print);
            }
        }
    }

使用DataOutputStream和DataInputStream读写文本

结果如下，将文件用二进制格式打开

image.png

其中char是2字节，int是4字节

public static void main(String[] args) {
        try {
            String fileUrl = BaseWriteFile.getFileUrl("G:/java_test/git/jBase/build/resources/main/file4WriteData.txt");
            DataOutputStream outputStream=new DataOutputStream(
                    new FileOutputStream(fileUrl)
            );
            outputStream.writeInt(33);
            outputStream.writeChar('b');

            //按顺序读出来
            DataInputStream inputStream=new DataInputStream(
                    new FileInputStream(fileUrl)
            );
            System.out.print(inputStream.readInt());
            System.out.print(inputStream.readChar());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

对象输入/输出流与序列化

public static void main(String[] args) {
        try {
            String fileUrl = BaseWriteFile.getFileUrl("G:/java_test/git/jBase/build/resources/main/file4WriteData.txt");
            try(ObjectOutputStream objectOutputStream=new ObjectOutputStream(
                    new FileOutputStream(fileUrl)
            );ObjectInputStream objectInputStream=new ObjectInputStream(
                    new FileInputStream(fileUrl)
            )) {
                Teacher teacher=new Teacher("小老师",11);
                objectOutputStream.writeObject(teacher);
                teacher=new Teacher("老老师",33);
                objectOutputStream.writeObject(teacher);
                //由于readObject()无法判断是否还有对象可读,所以自己放入一个null用来结束循环
                objectOutputStream.writeObject(null );
                Object o=objectInputStream.readObject();
                while (o!=null){
                    System.out.println(o);
                    o=objectInputStream.readObject();
                }
            }
        } catch (IOException | ClassNotFoundException e) {
            e.printStackTrace();
        }
    }

注意，这里Teacher类需要进行序列化

public class Teacher implements Serializable {
    private String name;//姓名
    private int age;//年龄

    public Teacher(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    @Override
    public String toString() {
        return "Teacher{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}