String类的常用方法

java.lang.String Class

在Java中，存储和处理字符串等相关功能的实现，用String类

String(String original);

int length();

char charAt(int index);

boolean equals(Object anObject);

int indexOf(int ch);

int indexOf(String str);

static String valueOf(type b);

public class StringClassDemo{
    public static void main(String[] args){
        String strHello = new String("hello");//字符串初始化方法1
        Sring strWorld = "World";//字符串初始化方法2

        strWorld = new string("hello");

        if(strHello == strWorld){//==比较的是字符串的引用是否相等
            system.out.println("The strings are equivalent according to ==");
        }else{
            system.out.println("The strings are not equivalent according to ==");
        }
        strWorld = "World";

        if(strHello.length() != strWorld.length()){
            system.out,println("not");
        }else{
            system.out.println("equal in length");
        }

        if(strHello.equals(strWorld)){//equals方法比较的是字符串的内容是否相等
            system.out.println("The strings are equivalent according to the method equals()");
        }

system.out,println(strHello.charAt(2));//获取当前字符串某一指定位置的一个字符
system.out,println(strWorld.indexOf("or"));//定位“or”在字符串中第一次出现的位置
system.out,println((strWorld + strHello).indexOf("o", 5));//用+进行字符串连接

String strValues;
strValues = String.valueOf(5.87);//"5.87"
strValues = String.valueOf(true);//"true"

    }
}