| 知乎专栏 |
Java 11 增加了一系列的字符串处理方法，如以下所示。
// 判断字符串是否为空白 " ".isBlank(); // true // 去除首尾空格 " Javastack ".strip(); // "Javastack" // 去除尾部空格 " Javastack ".stripTrailing(); // " Javastack" // 去除首部空格 " Javastack ".stripLeading(); // "Javastack "
package cn.netkiller.test;
public class Test {
public static void main(String[] args) {
String string = new String("http://www.netkiller.cn");
System.out.println("查找字符 . 第一次出现的位置: " + string.indexOf('.'));
System.out.println("从第15个字符位置查找字符 . 出现的位置:" + string.indexOf('.', 15));
}
}
public String randomString(String chars, int length) {
Random rand = new Random();
StringBuilder buf = new StringBuilder();
for (int i = 0; i < length; i++) {
buf.append(chars.charAt(rand.nextInt(chars.length())));
}
return buf.toString();
}
/**
* 获取4位随机验证码
* @return
*/
public static String getValidationCode(){
return String.valueOf((new Random().nextInt(8999) + 1000));
}
/**
* 获取6位随机验证码
* @return
*/
public static String getValidationCode(){
return String.valueOf((new Random().nextInt(899999) + 100000));
}
public class Test {
public Test() {
// TODO Auto-generated constructor stub
}
public static void main(String[] args) {
// TODO Auto-generated method stub
System.out.println("2010-09-11T20:00:30".replace("T", " "));
}
}
{"status":0,"message":"","bankcode":"ABOC;IBC;CCTB;ICBC"}
转换后
{\"status\":0,\"message\":\"\",\"bankcode\":\"ABOC;IBC;CCTB;ICBC\"}
package test;
public class str {
public static void main(String[] args) {
String jsonString = "{\"status\":0,\"message\":\"\",\"bankcode\":\"ABOC;IBC;CCTB;ICBC\"}";
System.out.println(jsonString);
System.out.println(jsonString.replace("\"", "\\\""));
}
}
查找特定字符并替换为找到的内容
package cn.netkiller.type;
public class ragexTest {
public ragexTest() {
// TODO Auto-generated constructor stub
}
public static void main(String[] args) {
// TODO Auto-generated method stub
String str = "<html>Netkiller</html>";
String regex = "<html>|</html>";
//运行结果返回 Netkiller
System.out.println(str.replaceAll(regex, ""));
// 运行结果返回 Neo
System.out.println("CN/NETKILLER/WWW/Neo_Chen".replaceAll(".*/(.+)_Chen", "$1"));
}
}
// 20200303 => 2020-03-03
date = date.replace(/(.{4})/, "$1-");
date = date.replace(/(.{7})/, "$1-");
用正则处理 Alertmanager 日期 rfc3339 格式 2021-08-23T01:30:30.2206015+08:00，Alertmanager 日期格式中有7位数的毫秒，使用 SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSXXX") 无法正常读取。
package cn.netkiller.alertmanager;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.TimeZone;
public class Test {
public Test() {
// TODO Auto-generated constructor stub
}
public static void main(String[] args) throws ParseException {
// TODO Auto-generated method stub
String rfc3339 = "2021-08-23T01:30:30.2206015+08:00";
rfc3339 = rfc3339.replaceAll(".[0-9]{7}", "");
System.out.println(rfc3339);
System.out.println(rfc3339.replaceAll("([0-9]{4})-([0-9]{2})-([0-9]{2})T([0-9]{2}):([0-9]{2}):([0-9]{2})+(.*)", "$1年$2月$3日 $4时$5分$6秒"));
System.out.println(rfc3339.replaceAll("([0-9]{4}-[0-9]{2}-[0-9]{2})T([0-9]{2}:[0-9]{2}:[0-9]{2})+(.+)", "日期：$1 时间：$2"));
// SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSXXX");
SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ssXXX");
simpleDateFormat.setTimeZone(TimeZone.getTimeZone("GMT+8"));
System.out.println(simpleDateFormat.parse(rfc3339).toString());
}
}
2021-08-23T01:30:30+08:00 2021年08月23日 01时30分30秒 日期：2021-08-23 时间：01:30:30 Mon Aug 23 01:30:30 CST 2021
替换一组字符串
String str1 = "广东省，福建省，北京市，海淀区，河北省，上海市";
str1 = str1.replaceAll("(省|市|区)", "");
System.out.println("替换多个中文：" + str1);
替换多个中文：广东，福建，北京，海淀，河北，上海
替换 Ascii
String string = "佛山市123南海区ABC精密abc机械有限公司,";
String clean = string.replaceAll("\\P{Print}", "");
System.out.println(clean);
Unicode 码表 https://www.ssec.wisc.edu/~tomw/java/unicode.html
String string = "2017-12-18 netkiller http://www.netkiller.cn - 网站正常";
System.out.println(string.replaceAll("[^\u4e00-\u9fa5]", ""));
例如： String str = "helloword!!!"; System.out.println(str.substring(1,4)); System.out.println(str.substring(3,5)); System.out.println(str.substring(0,4)); 将得到结果为： ell lo hell
Timestamp转化为String:
SimpleDateFormat df = new
SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); //定义格式，不显示毫秒
Timestamp now =
new Timestamp(System.currentTimeMillis());
//获取系统当前时间
String str =
df.format(now);
String转化为Timestamp:
SimpleDateFormat df = new
SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
String time = df.format(new
Date());
Timestamp ts = Timestamp.valueOf(time);
java11对String类新增了strip，stripLeading以及stripTrailing方法，除了strip相关的方法还新增了isBlank、lines、repeat(int)等方法
@Test
public void testStrip(){
String text = " \u2000a b ";
Assert.assertEquals("a b",text.strip());
Assert.assertEquals("\u2000a b",text.trim());
Assert.assertEquals("a b ",text.stripLeading());
Assert.assertEquals(" \u2000a b",text.stripTrailing());
}
package cn.netkiller.kubernetes;
public class Test {
public Test() {
}
public static void main(String[] args) {
String json = """
{
"name" : "netkiller",
"home" : "https://www.netkiller.cn/"
}
""";
System.out.println(json);
}
}
String[] string = topic.split("/");
Log.d("Service", string.length + "");
for (String str: string) {
Log.d("Service", str);
}
String str2 = new String("www.netkiller.cn");
for (String retval: str2.split("\\.", 3)){
System.out.println(retval);
}
System.out.println("");
String str3 = new String("acount=? and uu =? or n=?");
for (String retval: str3.split("and|or")){
System.out.println(retval);
}