Java正则、时间转换、将对象数组转换为字符数组、枚举构造器、BigDecimal转换

Java正则表达式

可参考教程：http://c.biancheng.net/view/5812.html

public static void main(String[] args) {
    
    
   String regex = "^\\w+[@].*\\.((com)|(cn))(\\.com|\\.cn)?";
   String b = "[email protected]";
   //还可以使用Pattern和Matcher,他们有很多方法，可参考https://www.runoob.com/java/java-tutorial.html
   //Pattern p = Pattern.compile(regex);
   //Matcher m = p.matcher(b);
   //System.out.println(m.matches());
   System.out.println(b.matches(regex));
  }

Java正则需要两个斜杠的原因

在线正则-regex100.com

Java：LocalDate,LocalDateTime,Date及时间戳的转换

LocalDate,LocalDateTime,Date及时间戳的转换
localDateTime获取时间指定日期格式

java中将对象数组转换为字符数组

Object[] obj= {
    
    "a","b","c"};
String[] stringArray = Arrays.stream(obj).toArray(String[]::new);
String[] stringArray = Arrays.copyOf(obj, obj.length, String[].class);
String[] stringArray = Arrays.asList(obj).toArray(new String[obj.length]);

→参考

java枚举构造器

java枚举构造器调用次数
java枚举构造器调用次数参考2
参考3

//自定义构造器的枚举
public enum Role {
    
    
    ROLE_PERSONAL("personal","个人"),
    ROLE_MANAGER("manager","单位"),
    ROLE_DIVISION("division","主管"),
    ROLE_UNDEFINED,//可以有参无参混合用，但是这种混合需要手动声明无参构造
    ;
    private String roleCode;
    private String roleName;

    Role() {
    
    }

    Role(String roleCode, String roleName) {
    
    
        this.roleCode = roleCode;
        this.roleName = roleName;
    }

    public String getRoleCode() {
    
    
        return roleCode;
    }

    public void setRoleCode(String roleCode) {
    
    
        this.roleCode = roleCode;
    }

    public String getRoleName() {
    
    
        return roleName;
    }

    public void setRoleName(String roleName) {
    
    
        this.roleName = roleName;
    }
}

类型转换

BigDecimal与long转换