The object is to write a text file

1. First create a Mybook objects

public class MyBook {
    private String name;
    private String author;
    private LocalDate date;

    public MyBook(){

    }
    public MyBook(String name,String author,int year,int month,int day){
        this.name=name;
        this.author=author;
        this.date=LocalDate.of(year,month,day);
    }

    public String getName() {
        return name;
    }

    public String getAuthor() {
        return author;
    }

    public LocalDate getDate() {
        return date;
    }
}

2. Write operation

public class MyFileTest {

    public static void main(String[] args) throws FileNotFoundException {
        //初始化数组
        MyBook[] books=new MyBook[4];
        books[0]=new MyBook("coreJava","Unknown",2012,2,6);
        books[1]=new MyBook("coreJava","Unknown",2012,2,6);
        books[2]=new MyBook("coreJava","Unknown",2012,2,6);
        books[3]=new MyBook("coreJava","Unknown",2012,2,6);
        //写操作
        try(PrintWriter out=new PrintWriter(new FileOutputStream("book.txt"))){
            writeData(out,books);
        }
    }

    private static void writeData(PrintWriter out, MyBook[] books) {
        Out.println (books.length); // outputs are several objects, the latter use to read 
        for (MyBook the myBook: Books) {
            writeBook(out,myBook);
        }
    }

    private static void writeBook(PrintWriter out, MyBook myBook) {
        out.println(myBook.getName()+"|"+myBook.getAuthor()+"|"+myBook.getDate());
    }
}

Note：

1.PrintWriter objects: text print format strings and numbers, is a subclass of Writer

　　Common constructors: /PrintWriter(String fileName, String csn)PrintWriter(OutputStream out)，这里采用的第二种，FileOutputStream是OutputStream的子类

try 2. stream {} with: automatically performing close (after completion of program execution)

3.InputStream / OutputStream: reads / writes a sequence of bytes of input and output streams

   Reader / Writer: read two-byte sequence based on the value of char

   Usually read and write operations write their subclasses using a discharge method in the present embodiment, the use PrintWriter println () output

4.FileInputStream / FileOutputStream no specific method for read and write text, (read (), write () can only read a single byte), their role is to obtain flow.

　　Stream to construct the object having the corresponding functions.