类型互转

1.各种类型转String

2.String转Bytes

3.数组转List

4.进制转换

5.

parse 在 SimpleDateFormat 中是转换为Date类,其它的一些包装类都是转换为int/double等基本类

valueOf 转换的是类 eg: Integer /Double/Float....

import java.lang.reflect.Constructor;import java.lang.reflect.InvocationTargetException;import java.util.Arrays;import java.util.HashMap;import java.util.List;import java.util.Map;import java.util.Map.Entry;import java.util.Scanner;public class Main {		public static void main(String[] args) throws Exception {		Integer a = 12;				Integer [] aaa = new Integer[10];		for(int i = 0;i<10;i++)			aaa[i] = new Integer(i);//对象数组要一个一个new		System.out.println(Arrays.toString(aaa));//自己主动拆包 数组转String		System.out.println(Integer.toBinaryString(a));//String		System.out.println(Integer.toHexString(a));//String		String t = "23";		byte [] b = t.getBytes();		Integer aa = Integer.parseInt(t, 10);		System.out.println(aa);		List list = Arrays.asList(aaa);			System.out.println(list);		aaa = (Integer [])list.toArray(new Integer[0]);		System.out.println(Arrays.toString(aaa));	}}/* * [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] *1100 *c *23 *[0, 1, 2, 3, 4, 5, 6, 7, 8, 9] *[0, 1, 2, 3, 4, 5, 6, 7, 8, 9] */class Child extends Main {	}