Question

java判断字符串里面有几个某字符

Answer 1

public static void StringCount(){
String str = "ddsfasdfwedEEETGERDASDdd";
int count=0;
for(int i=0;i<str.length();i++){
String s = String.valueOf(str.charAt(i)); //char 类型转String
if(s.equals("a")){
count++;
}
}
System.out.println(count);
}

Answer 2

String a = "";
System.out.println(a.isEmpty()); // 是否为空 true
System.out.println(a.length()); // 长度 0
a = "12345jack";
System.out.println(a.isEmpty()); // 是否为空 false
System.out.println(a.length()); // 长度 9