StringBuilder，String, int转为String

package com.company.project.builder;

import java.util.Random;

public class StringBuilderDemo {

public static void main(String[] args) {
StringBuilder sb = new StringBuilder("政立路477号1号楼");
//插入，从第三个插入，第三个之后的后移,结果：政立路hehe477号1号楼
System.out.println(sb.insert(3, "hehe"));
String str = "candsjkfdskgcanfskfdldscan";
//找不到返回-1
System.out.println(str.indexOf("e"));
//20位之后的第一个can,结果：23
System.out.println(str.indexOf("can",20));
//是否以cani开始
System.out.println(str.startsWith("cani"));
//是否以scan3结尾
System.out.println(str.endsWith("scan3"));
//转为大写
System.out.println(str.toUpperCase());
//区index：3之后的部分
System.out.println(str.substring(3));
str=" zha ng    ";
System.out.println(str);
//去除前后的空格和tab
System.out.println(str.trim());
System.out.println(str);
/**
* 取得8位密码
*/
String ran = "";
Random random = new Random();
for(int i=0;i<8;i++){
int num = random.nextInt(3);
switch(num){
case 0:
//随机小字母
char c = (char)(random.nextInt(26)+'a');
ran += c;
break;
case 1:
//随机大字母
c = (char)(random.nextInt(26)+'A');
ran += c;
case 2:
//随机数字
int ii = random.nextInt(10);
ran += ii;
}
}
System.out.println(ran);//结果：rU4havg6C0

int i1 = 1;
//int转为String,以下2个方式
System.out.println(String.valueOf(i1)+222);
System.out.println(i1+"");
}

}