Java基础——常用类型转换

Posted 2020-10-23 Wayfo

关于类型转化问题：

(1)String---------》char / char[ ]

String str = "ab";
char str1 = str.charAt(0); //得到a
char str2 = str.charAt(1); //得到b

char[ ] str3 = str.toCharArray();
System.out.println (Arrays.toString(str3));

(2)char / char[]-----------》String

char m = ‘a‘;
String str = String.valueOf(m);
String str2 = m + " ";

char[] m = {‘a‘,‘b‘};
String str3 = String.copyValueOf(m);
String str4 = new String(m);

 (3)int -----------》 String

int i;
String s = String.valueOf(i);
String s = Integer.toString(i);
String s = "" + i;

 (4)String ----------》 int

注意： Integer.parseInt(s)转换的只能是数字字符串

String s = "1";
int i = Integer.parseInt(s);
String str = "123";
i = Integer.parseInt(str,10);
i = Integer.valueOf(s).intValue()