用Java实现各种数据结构
在同步的情况下 StringBuilder好于“+”、contact、StringBuffer和StringUtils.join 在异步的情况下使用StringBuffer 因为它是线程安全的
String a = "dfda"
String b = "ddsaf"
String hello = a + b
String helloC = a.contact(b)
StringBuffer stringBuffer = new StringBuffer("stringBuffer");
StringBuffer helloBuffer = stringBuffer.append("hello");
StringBuilder stringBuilder = new StringBuilder("stringBuilder");
StringBuilder helloBuilder = stringBuilder.append("hello");
String []str = {"ewqe","fera"};
String result = StringUtils.join(str,",") //ewqe,fera