1.StringBuilder转换为String

public string toString():通过toString就可以实现把StringBuilder转换为String

2.String转换为StringBuilder

public StringBuilder(String s):通过构造方法就可以实现把String转换为StringBuilder

package com.ithema_15;
/*
   1.StringBuilder转换为String
        public string toString():通过toString就可以实现把StringBuilder转换为String
   2.String转换为StringBuilder
        public StringBuilder(String s):通过构造方法就可以实现把String转换为StringBuilder
 */

public class StringBuilderDemo03 {
    public static void main(String[] args){
        /*
        //StringBuilder转换为String
        StringBuilder sb = new StringBuilder();
        sb.append("hello");

    // String s = sb; //这个是错误的做法

        //public string toString():通过toString就可以实现把StringBuilder转换为String
        String s = sb.toString();
        System.out.println(s);
        */


      //String转换为StringBuilder
        String s = "hello";
      //  StringBuilder sb = s; //这个方法是错误的

        //public StringBuilder(String s):通过构造方法就可以实现把String转换为StringBuilder
        StringBuilder sb = new StringBuilder(s);
        System.out.println(sb);

    }
}