//5种构造方法
public void Con(){ String str = "sfaj"; String str1 = new String("sfajdf"); String str2 = new String(); str2 = "sfaj"; char[] cArr = {'s','f','a','d','f','j'}; String str3 = new String(); String str4 = new String(cArr,0,2); } public void pra(){ String str = new String("sfajdfjal;fjje23jkdjfa jdkf"); //equals:相等 System.out.println(str.equals("dddd")); //startsWith() && endsWith(); System.out.println(str.startsWith("sfa")); System.out.println(str.endsWith("kf")); //compareTo() System.out.println("ac".compareTo("ad")); System.out.println("ac".compareTo("af")); } @Test public void prac(){// String str = new String("sfajdfjal;fjje23jkdjfa jdkf"); //indexOf(); System.out.println(str.indexOf("s")); System.out.println(str.indexOf("f", 7)); //lastIndexOf(str);lastIndexOf(str,int end) System.out.println(str.lastIndexOf("j")); System.out.println(str.lastIndexOf("j",10)); //subString(int start);subString(int start,int end) start开始,end以前 System.out.println(str.substring(20)); System.out.println(str.substring(10,14)); }public void pract(){
String str = new String(" sfajdfjal;fjje23jkdjfa jdkf "); //replaceAll(str,str1); String str2 = str.replace("f", "哒哒哒"); System.out.println(str2); //trim:去除前后的空格 String str3 = str.trim(); System.out.println(str3); //split();拆分 String[] str4 = str.split("f"); for(String s : str4){ System.out.println(s); } }