java中实用的开发工具函数

梁霖编程工具库 2023-01-10

176

MD5工具函数

在存储用户一些敏感信息的时候，需要考虑将这部分敏感信息通过md5加密以后再存储到数据库中，防止用户的敏感信息暴露。

 public static String MD5(String data)  {
        try {
            java.security.MessageDigest md = MessageDigest.getInstance("MD5");
            byte[] array = md.digest(data.getBytes("UTF-8"));
            StringBuilder sb = new StringBuilder();
            for (byte item : array) {
                sb.append(Integer.toHexString((item & 0xFF) | 0x100).substring(1, 3));
            }
            return sb.toString().toUpperCase();
        } catch (Exception exception) {}
        return null;
 }

从request请求中获取用户的ip地址

public static String getIpAddr(HttpServletRequest request) {
        String ipAddress = null;
        try {
            ipAddress = request.getHeader("x-forwarded-for");
            if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
                ipAddress = request.getHeader("Proxy-Client-IP");
            }
            if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
                ipAddress = request.getHeader("WL-Proxy-Client-IP");
            }
            if (ipAddress == null || ipAddress.length() == 0 || "unknown".equalsIgnoreCase(ipAddress)) {
                ipAddress = request.getRemoteAddr();
                if (ipAddress.equals("127.0.0.1")) {
                    // 根据网卡取本机配置的IP
                    InetAddress inet = null;
                    try {
                        inet = InetAddress.getLocalHost();
                    } catch (UnknownHostException e) {
                        e.printStackTrace();
                    }
                    ipAddress = inet.getHostAddress();
                }
            }
            // 对于通过多个代理的情况，第一个IP为客户端真实IP,多个IP按照','分割
            if (ipAddress != null && ipAddress.length() > 15) {
                // "***.***.***.***".length()
                // = 15
                if (ipAddress.indexOf(",") > 0) {
                    ipAddress = ipAddress.substring(0, ipAddress.indexOf(","));
                }
            }
        } catch (Exception e) {
            ipAddress="";
        }
        return ipAddress;
    }

Json字符串和对象之间的相互解析

import com.fasterxml.jackson.databind.ObjectMapper;


public class JsonUtil {
    private static final ObjectMapper MAPPER = new ObjectMapper();
    /**
     * 把对象转字符串
     * @param data
     * @return
     */
    public static String objectToJson(Object data){
        try {
            return MAPPER.writeValueAsString(data);
        }catch (Exception e){
            e.printStackTrace();
        }
        return null;
    }


    /**
     * json字符串转对象
     * @param jsonData
     * @param beanType
     * @param <T>
     * @return
     */
    public static <T> T jsonToPojo(String jsonData, Class<T> beanType){
        try {
            T t = MAPPER.readValue(jsonData,beanType);
            return t;
        }catch (Exception e){
            e.printStackTrace();
        }
        return null;
    }
}

验证一个字符串是否是邮箱或手机号码‍‍‍

import java.util.regex.Matcher;
import java.util.regex.Pattern;


/**
 * 邮箱手机号码验证工具类
 */
public class CheckUtil {


    /**
     * 邮箱正则
     */
    private static final Pattern MAIL_PATTERN = Pattern.compile("^([a-z0-9A-Z]+[-|\\.]?)+[a-z0-9A-Z]@([a-z0-9A-Z]+(-[a-z0-9A-Z]+)?\\.)+[a-zA-Z]{2,}$");


    /**
     * 手机号正则，暂时未用
     */
    private static final Pattern PHONE_PATTERN = Pattern.compile("^((1[3-9][0-9])|(15[^4,\\D])|(18[0,5-9]))\\d{8}$");


    /**
     * @param email
     * @return
     */
    public static  boolean isEmail(String email) {
        if (null == email || "".equals(email)) {
            return false;
        }
        Matcher m = MAIL_PATTERN.matcher(email);
        return m.matches();
    }


    /**
     * 暂时未用
     * @param phone
     * @return
     */
    public static boolean isPhone(String phone) {
        if (null == phone || "".equals(phone)) {
            return false;
        }
        Matcher m = PHONE_PATTERN.matcher(phone);
        return m.matches();


    }
}

生产指定长度的随机验证码

/**
 * 获取随机length长度的验证码
 * @param length
 * @return
 */
public static String getRandomCode(int length){
    //验证码字符集
    String sources = "0123456789";
    Random random = new Random();
    StringBuilder sb = new StringBuilder();
    for(int j=0; j<length; j++){
        sb.append(sources.charAt(random.nextInt(9)));
    }
    return sb.toString();
}

时间类型和字符串类型的转换

public class TimeUtil {


    /**
     * 默认日期格式
     */
    private static final String DEFAULT_PATTERN = "yyyy-MM-dd HH:mm:ss";


    /**
     * 默认日期格式
     */
    private static final DateTimeFormatter DEFAULT_DATE_TIME_FORMATTER  = DateTimeFormatter.ofPattern(DEFAULT_PATTERN);


    private static final ZoneId DEFAULT_ZONE_ID = ZoneId.systemDefault();




    /**
     * LocalDateTime 转 字符串，指定日期格式
     * @param time
     * @param pattern
     * @return
     */
    public static String format(LocalDateTime localDateTime, String pattern){
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern(pattern);
        String timeStr = formatter.format(localDateTime.atZone(DEFAULT_ZONE_ID));
        return timeStr;
    }




    /**
     * Date 转 字符串, 指定日期格式
     * @param time
     * @param pattern
     * @return
     */
    public static String format(Date time, String pattern){
        DateTimeFormatter formatter = DateTimeFormatter.ofPattern(pattern);
        String timeStr = formatter.format(time.toInstant().atZone(DEFAULT_ZONE_ID));
        return timeStr;
    }


    /**
     *  Date 转 字符串，默认日期格式
     * @param time
     * @return
     */
    public static String format(Date time){


        String timeStr = DEFAULT_DATE_TIME_FORMATTER.format(time.toInstant().atZone(DEFAULT_ZONE_ID));
        return timeStr;
    }


    /**
     * timestamp 转 字符串，默认日期格式
     *
     * @param time
     * @return
     */
    public static String format(long timestamp) {
        String timeStr = DEFAULT_DATE_TIME_FORMATTER.format(new Date(timestamp).toInstant().atZone(DEFAULT_ZONE_ID));
        return timeStr;
    }




    /**
     * 字符串 转 Date
     *
     * @param time
     * @return
     */
    public static Date strToDate(String time) {
        LocalDateTime localDateTime = LocalDateTime.parse(time, DEFAULT_DATE_TIME_FORMATTER);
        return Date.from(localDateTime.atZone(DEFAULT_ZONE_ID).toInstant());


    }




    /**
     * 获取当天剩余的秒数,用于流量包过期配置
     * @param currentDate
     * @return
     */
    public static Integer getRemainSecondsOneDay(Date currentDate) {
        LocalDateTime midnight = LocalDateTime.ofInstant(currentDate.toInstant(),
                ZoneId.systemDefault()).plusDays(1).withHour(0).withMinute(0)
                .withSecond(0).withNano(0);
        LocalDateTime currentDateTime = LocalDateTime.ofInstant(currentDate.toInstant(),
                ZoneId.systemDefault());
        long seconds = ChronoUnit.SECONDS.between(currentDateTime, midnight);
        return (int) seconds;
    }
}

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java中实用的开发工具函数

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