JAVA-各种类型之间转换 parse() 与valueOf()

类型互转1.各种类型转String2.String转Bytes3.数组转List4.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 {}