java字符串学习笔记.doc

字符串3月12日字符串笔记例子：package .String;import java.util.Scanner;import java.util.regex.Matcher;import java.util.regex.Pattern;public class test public static void t1(String val)/public static void t1()/String val=cdsfewfdsfdsb;/Pattern p=Ppile(a*b);/符合a出现零次或多次，以b结尾/Pattern p=Ppile(a+b);/符合a出在一次或多次，以b结尾/Pattern p=Ppile(a*b$);/必须以b为结尾Pattern p=Ppile(as*b$);Matcher m=p.matcher(val);if(m.find()System.out.println(OK);elseSystem.out.println(NO);public static void main(String args) /*StringBuilder sb=new StringBuilder();if(args!=null&args.length0)for(String val:args)/System.out.println(val+);/加+“”是为了换行sb.append(val);System.out.println(sb.toString();*/ Scanner s=new Scanner(System.in); String b=s.next();test t=new test();/t.t1();t.t1(b);另外一个例子：package .String;public class Test1 /* * 构造器 */private static String val;public static int accout=0;public Test1()/无参构造器/构造器，帮我们初始化一些实例 val = -ab-$temp-cdef,-13$temp131-3131,-fff$tempffff;public static void c1()val=fsdfsdf;/注意如果private static String val;声明的时候是非static时会报错public Test1(String value)/有参构造器this.val=value;public static void main(String args) Test1 xt = new Test1();/*System.out.println(xt); Test1 xt2=new Test1(sadfsafsd); System.out.println(xt2);*/ for(int i=0;i100;i+) System.out.println(+Test1.accout);/相当于计数器 package .String;public class testStringBuiler /* * param args */public static void main(String args) StringBuilder builder=new StringBuilder();long beginTime = System.currentTimeMillis();for(int i=0;i1000;i+)builder.append(String.valueOf(i);long endTime = System.currentTimeMillis();System.out.println(运行时间：+(endTime-beginTime);package .String;import java.util.regex.Matcher;import java.util.regex.Pattern;public class xiTi /* *正则表达式 *输入-abcdef,131313131,-fffffff * * 用下列的方法实现： split() Pattern() replace() * 体会正则表达式 * * 实现结果为： * abcdef * 131313131 * ffffff */*public void t() /自己的方法String str = -ab-cdef,-13131-3131,-fffffff;Pattern p = Ppile(-);String vals = str.split(,);for (String s : vals) Matcher m = p.matcher(s);if (m.find() /find()方法 String line = s.replace(-, );System.out.println(line); else System.out.println(没有成功);*/老师的方法，用很多方法实现String val = -ab-cdef,-13131-3131,-fffffff;public String spilt()return val.split(,);public String pattern()Pattern p = Ppile(-);String vals=spilt();StringBuffer sb=new StringBuffer();for (String val : vals) Matcher m = p.matcher(val);/开始配if (m.find() /find()方法 String newline = val.replace(-, );sb.append(newline+n); else sb.append(val+n);return sb.toString();public void test()val.replace(-, );public static void main(String args) xiTi xt = new xiTi();String val=xt.pattern();System.out.println(val);/System.out.println(xt.pattern();package .String;import java.util.regex.Matcher; import java.util.regex.Pattern;public class xiTi2 /* * -ab-tempcdef,-13131-3131,-fffffff */private String val = -ab-$temp-cdef,-13$temp131-3131,-fff$tempffff; public String getVal() return val;public void setVal(String val) this.val = val;public String spilt()return val.split(,);public String Pattern()Pattern p = Ppile($(w*);/正则表达式/$(w*)的作用是:为解析 ，$配，w*为任何字符String vals=spilt();StringBuffer sb=new StringBuffer();for (String val : vals) Matcher m = p.matcher(val);/开始匹陪if (m.find() /find()方法 /0=$tempSystem.out.println(0=+m.group(0);/group()方法/1=tempSystem.out.println(1=+m.group(1);String cv=m.group(1);String newline = val.replace(-, ).replace(cv, test).replace($, ).replace(, );sb.append(newline+n); else sb.append(val+n);return sb.toString();public String pattern2()Pattern p = Ppile(-);String vals=spilt();StringBuffer sb=new StringBuffer();for (String val : vals) Matcher m = p.matcher(val);/开始配if (m.find() /find()方法 String newline = val.replace(-, );sb.append(newline+n); else sb.append(val+n)