Java ???? ??? ???? ??: 1. ??? ?? [Integer.parseInt(String s)] 2. ?? ??? ?? [Float.parseFloat(String s)]? ??.
?? ?? ?? ????: java ?? ????
Java ???? ??? ???? ??:
1. ??? ??
(1) Integer.parseInt( String s), ?? ??? ??? ????:
public class Test {
public static void main(String args[]){
String s = "123";
int num = Integer.parseInt(str);
int sum = num + 100;
System.out.println("Result is: "+sum); // 輸出結(jié)果為：Result is: 223
}}
(2) Integer.valueOf(String s), ?? ??? ??? ????:
public class Test2 {
public static void main(String args[]){
String s = "-100";
int num = Integer.valueOf(str);
int sum = num + 101;
System.out.println("Result is: "+sum); // 輸出結(jié)果為：Result is: 1
} }
2. (1) Float.parseFloat(String s), ?? ??? ??? ????.
public class Test {
public static void main(String args[]){
String s = "123.11";
float num = Float.parseFloat(s);
float sum = num + 100;
System.out.println("Result is: "+sum); // 輸出結(jié)果為：Result is: 223.11
}}
(2) Double.parseDouble(String s), ?? ??? ??? ????.
public class Test2 {
public static void main(String args[]){
String s = "100.01";
double num = Double.parseDouble(s);
double sum = num + 100;
System.out.println("Result is: "+sum); // 輸出結(jié)果為：Result is: 200.01
}}
The ???? ??? s="00000123"? ?????. 123?? ??? ?? ??? ??? ????.
public class Test {
public static void main(String args[]){
String s = "00000123";
int num = Integer.parseInt(s);
System.out.println("Result is: "+num); // 輸出結(jié)果為：Result is: 123
}}
1 Java?? ?? ? ?? ??? ??? ???? ??:
public class Test {
public static void main(String args[]){
int i = 11;
String s = i + ""; // 方法一
String s = String.valueOf(i); // 方法二
String s = Integer.toString(i); // 方法三
} }
2. Java? ???? ???? ??:
public static boolean isNumeric(String str){
for (int i = str.length();--i>=0;){
if (!Character.isDigit(str.charAt(i))){
return false;
} }
return true;
}
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