package com.itheima;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
public class 各种转换 {
public static void main(String[] args) throws ParseException {
/*
* 1.基本数据类型转换
*/
//隐式转换 byte,short,char -- int -- long -- float -- double
//强制转换
int a = 12;
byte b = (byte) a;
/*
* 2.String StringBuilder
*/
//String to StringBuilder
StringBuilder sb = new StringBuilder("abcde");
//StringBuilder to String
String s = sb.toString();
/*
* 3.String 和 数组
*/
//String to 数组
String ss = "abcdefg";
char[] charArray = ss.toCharArray();
byte[] bytes = ss.getBytes();
//数组 to String
String bys = new String(bytes);
String chs = new String(charArray);
*4 String 和 基本数据类型
//基本数据类型 to String
int an = 10;
String aa = an+"";
String aa1 = String.valueOf(an);
//String to 基本数据类型
int bb = Integer.parseInt("123");
//String to int
char charAt = "123".charAt(0);
//String to char
/*
*5 String 大小写转
*/
String bigSmall = "AbCdEf";
String big = bigSmall.toUpperCase();
String small = bigSmall.toLowerCase();
/*
*6 自动装箱和拆箱
*/
Integer i = 123;//自动装箱
int ii = i; //自动拆箱
/*
*7 Date 和 String
Date d = new Date();
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String format = sdf.format(d);
//Date to String
Date parse = sdf.parse(format);
//String to Date
* 8 Date 和 Calendar
Date date = new Date();
Calendar cal = Calendar.getInstance();
Date time = cal.getTime();
//Calendar to Date
cal.setTime(date);
//Date to Calendar