本文共 1088 字，大约阅读时间需要 3 分钟。

package com.bjsxt.builder;

/**

• StringBuilder的使用

• 最常用的操作

• StringBuilder builder = new StringBuilder(“中华人民共和国”);// String—>StringBuilder

• builder.append(“北京市”);

• String str = builder.toString(); //StringBuilder—>String

• 使用场合是什么？SQL语句的拼接

• StringBuilder builder = new StringBuilder(" select * from job where 1= 1 ");

• if(sal>10000){

• builder.append(" and sal >"+sal);

• }

• if(site != null){

• builder.append(" and site ="+site);

• }

• if(position != null){

• builder.append(" and position = "+ position);

• }

• String sql = builder.toString()

  */
  public class TestStringBuilder {
  public static void main(String[] args) {
  //1.创建一个StringBuilder对象
  //StringBuilder builder = new StringBuilder();
  StringBuilder builder = new StringBuilder(“中华人民共和国”);

  //2.对StringBuilder进行操作//2.1 末尾追加builder.append("北京市");builder.append("大兴区");builder.append("亦庄开发区");builder.append("北京尚学堂");//2.2 中间添加builder.insert(7,"华北地区");//2.4 删除builder.delete(7,11);builder.deleteCharAt(12);//2.3 修改操作

  builder.replace(0, 7, “中国”);

  //2.5 反转//builder.reverse();//2.6 StringBuilder--->StringString str = builder.toString();System.out.println(str);

  }

  }