1.lengtn():
获取字符串长度
2.isEmpty():
确认字符串是否为空
3.charAt(int index):
获取Index索引处字符的值
public class StrSource {
public static void main(String[] args) {
String str = "hello world";
System.out.println(str.length());
System.out.println(str.isEmpty());
System.out.println(str.charAt(1));
}
}
输出结果:
4.getChars(int srcBegin, int srcEnd, char dst[], int dstBegin)
srcBegin:字符串中要复制的第一个字符的索引
srcEnd:字符串中要复制的最后一个字符之后的索引
dst[]:目标数组
dstBegin:目标数组起始下标
public class StrSource {
public static void main(String[] args) {
String str = "hello world";
char[] arr = new char[12];
str.getChars(0,8,arr,0);
System.out.println(Arrays.toString(arr));
}
}
输出结果:
5.equals()
比较两个字符串的值
public class StrSource {
public static void main(String[] args) {
String str = "hello world";
String str1 = "world hello";
System.out.println(str.equals(str1));//false
}
}
6.compareTo()
字符串值的大小比较按照ASCII码的大小比较,大于返回正数,小于返回负数,等于返回0
String str = "abcdef";
String str1 = "abcde";
System.out.println(str.compareTo(str1));//正数1
7.hashCode()
返回对象的哈希码值
String str = "abcde";
String str1 = "Hello world";
System.out.println(str.hashCode());//92599395
System.out.println(str1.hashCode());//-832992604
8.indexOf()
返回字符在字符串中首次出现的位置,没有返回-1;
String str = "Helloworld";
int i = str.indexOf('w',0);
System.out.println(i);//5
9.regionMatches(boolean ignoreCase, int toffset,String other, int ooffset, int len)
ignoreCase:如果为 true,则比较字符时忽略大小写
toffset:此字符串中子区域的起始位置
other:目标字符串
ooffset:目标字符串中起始位置
len:要比较的长度
String str = "Helloworld";
String str1 = "hello world";
System.out.println(str.regionMatches(true,0,str1,0,5));//true
10.replace()
替换字符串中指定内容
String str = "Hello world";
String str1 = "hello world";
System.out.println(str.replace("Hel","www"));//wwwlo world
11.split(String regex, int limit)
返回由limit分割的字符串数组
String str = "Here is Tulun";
String[] word = str.split(" ");//返回由“ ”分割的字符串
System.out.println(Arrays.toString(word));
12.toLowerCase()
用于把字符串转换为小写
13.toUpperCase()
用于把字符串转换为大写
String str = "Here is Tulun";
System.out.println(str.toLowerCase());//here is tulun
System.out.println(str.toUpperCase());//HERE IS TULUN
14。toCharArray()
将字符串转换成char类型数组存放
String str = "Here is Tulun";
char[] arr = str.toCharArray();
System.out.println(Arrays.toString(arr));
//[H, e, r, e, , i, s, , T, u, l, u, n]
15.valueOf()
valueOf() 方法返回 Array 对象的原始值
16.copyValueOf()
拷贝指定范围内的值
char[] array = {'a','b','c','d','e'};
System.out.println(String.valueOf(array));//abcde
System.out.println(String.copyValueOf(array,1,3));//bcd
17.toString()
将任何对象转换成字符串表达形式
char[] array = {'a','b','c','d','e'};
array.toString();
System.out.println(array);//abcde