Java Basics-Day 15th

First, Date class

Construction method [2]

Date--Long Interchange

Date d = new Date ();

Date D1 = new Date ();

D1.gettime ();

D1.settime ();

Second, DateFormat class

Formatting: Date--String

Parsing: String--Date

SimpleDateFormat class [extends DateFormat]

Public final String format (date date):D ate--String

Time format: yyyy mm month DD Day HH:MM:SS HH:mm:ss YYYY/MM/DD HH:mm:ss

YYYY MM month DD Day YYYY-MM-DD HH:MM:SS

Parsing: String--Date

Public Date Parse (String str);//string--Date

Third, Calendar class

Get any calendar field from the calendar, combine as needed

[GregorianCalendar extends Calendar]

public int get (int field): Parameter is Calendar field year MONTH DATE HOUR MINUTE SECOND

MONTH: The range is 0~11 Second: can be judged at output ((Second>9?second: "0" +second));

Example: Calculate the number of days in February for any year "2"

Add () Subtracts the given calendar, plus the specified time

In the development, the definition class: No parameter constructs must give; when giving the parameter, the full parameter is given.

Object array: The address value of the object is stored-keyboard input data

Iv. User Login and Registration

More in line with object-oriented:

A: Determine the number of classes

B: Determine the functionality of each class

C: Maintaining relationships between classes

Classification of classes:

Basic class entity class---Simple description cn.itcast.pojo cn.itcast: Company domain name anti-write

Action class----action on entity classes

Cn.itcast.dao: operator interface

Cn.itcast.dao.impl: specific Operation implementation class

Test class---There is no such package in real development

Subcontracting of the class:

A: by module: cn.itcast.student

Cn.itcast.student.add

Cn.itcast.student.update

Cn.itcast.student.delete

Cn.itcast.student.find

Cn.itcast.teacher

Cn.itcast.teacher.add

cn.itcast.teacher.update^ ^^ ^^

B: By operation points: Cn.itcast.add

Cn.itcast.add.student

Cn.itcast.add.teacher

Cn.itcast.update

cn.itcast.update.student^ ^^

Note: When writing a method, the parameter is more than three, passing the object

Console class--Password display related

Java Basics-Day 15th