String类

r囧r小猫 2022-09-23 08:13 118阅读 0赞

string= “abcd ”  
string1=”ABCD ’  
string2=”learn by heart”  
string3=”heart”

public class test {
        public static void main(String[] args){
            char chars[]={
       'a','b','c','d',' '};
            String string=new String(chars );
    
            //获取字符串长度
            int len=string.length();
            System.out.println(len);
    
            //截取一个字符
            char ch;
            ch="abc".charAt(1);
            System.out.println(ch);
    
            //截取多个字符
            String string2="learn by heart";
            char buf[]=new char[20];
            string2.getChars(9,14,buf,0);
            System.out.println(buf);
    
            //比较字符串
            String string1="ABCD ";
            System.out.println(string.equals(string1));
            System.out.println(string.equalsIgnoreCase(string1));
    
            //比较特点区域
            String string3="heart";
            System.out.println(string3.regionMatches(10,string2,0,5));
    
            //检索
            System.out.println(string.lastIndexOf("b"));
            System.out.println(string.lastIndexOf("cd"));
    
    
            //截取
            System.out.println(string.substring(2,5));
            System.out.println(string.substring(1,3));
    
            //连接
            System.out.println(string.concat(string2));
    
            //替换
            string2 = string2.replace("learn",string3);
            System.out.println(string2);
    
            //返回哈希码
            System.out.println(string.hashCode());
            System.out.println(string2.hashCode());
    
            //大小写转换
            System.out.println(string.toUpperCase());
            System.out.println(string1.toLowerCase());
    
            //删除开头或结尾的空格
            System.out.println(string.trim());
    
            //在字符串中插入或删改
            StringBuffer str = new StringBuffer("this is a string ");
            str.insert(9, " new");
            System.out.println(str.toString());
    
            str.setCharAt(0,'T');
            System.out.println(str.toString());
    
            str.append(" test");
            System.out.println(str.toString());
    
            }
    }

![这里写图片描述][20160706223858135]

[20160706223858135]: /images/20220721/4853b6daebeb400e81b31ceaeddef040.png