工具类

• 获取ip
• MD5加密
• 获取验证码随机数
• 获取当前时间戳
• 获取随机长度的串
• 响应json数据给前端

import com.fasterxml.jackson.databind.ObjectMapper;
import lombok.extern.slf4j.Slf4j;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.security.MessageDigest;
import java.util.Random;
import java.util.UUID;

@Slf4j
public class CommonUtil {


    /**
     * 获取ip
     *
     * @param request
     * @return
     */
    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;
    }


    /**
     * MD5加密
     *
     * @param data
     * @return
     */
    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;

    }


    /**
     * 获取验证码随机数
     *
     * @param length
     * @return
     */
    public static String getRandomCode(int length) {

        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();
    }


    /**
     * 获取当前时间戳
     *
     * @return
     */
    public static long getCurrentTimestamp() {
        return System.currentTimeMillis();
    }


    /**
     * 生成UUID
     *
     * @return
     */
    public static String generateUUID() {
        return UUID.randomUUID().toString().replaceAll("-", "").substring(0, 32);
    }


    /**
     * 获取随机长度的串
     *
     * @param length
     * @return
     */
    private static final String ALL_CHAR_NUM = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";

    public static String getStringNumRandom(int length) {
        Random random = new Random();
        StringBuilder saltString = new StringBuilder(length);
        for (int i = 0; i < length; i++) {
            saltString.append(ALL_CHAR_NUM.charAt(random.nextInt(ALL_CHAR_NUM.length())));
        }
        return saltString.toString();
    }

    /**
     * 响应json数据给前端
     *
     * @param response
     * @param obj
     */
    public static void sendJsonMessage(HttpServletResponse response, Object obj) {
        ObjectMapper objectMapper = new ObjectMapper();
        response.setContentType("application/json; charset=utf-8");

        try (PrintWriter writer = response.getWriter()) {
            writer.print(objectMapper.writeValueAsString(obj));
            response.flushBuffer();
        } catch (IOException e) {
            log.warn("响应前端json数据给前端异常:{}", e);
        }
    }
}

接口统一协议 JsonData工具类

@Data
@AllArgsConstructor
@NoArgsConstructor
public class JsonData {

    /**
     * 状态码 0 表示成功，1表示处理中，-1表示失败
     */

    private Integer code;
    /**
     * 数据
     */
    private Object data;
    /**
     * 描述
     */
    private String msg;


    /**
     * 成功，传入数据
     * @return
     */
    public static JsonData buildSuccess() {
        return new JsonData(0, null, null);
    }

    /**
     *  成功，传入数据
     * @param data
     * @return
     */
    public static JsonData buildSuccess(Object data) {
        return new JsonData(0, data, null);
    }

    /**
     * 失败，传入描述信息
     * @param msg
     * @return
     */
    public static JsonData buildError(String msg) {
        return new JsonData(-1, null, msg);
    }

   
    /**
     * 自定义状态码和错误信息
     * @param code
     * @param msg
     * @return
     */
    public static JsonData buildCodeAndMsg(int code, String msg) {
        return new JsonData(code, null, msg);
    }

    /**
     * 传入枚举，返回信息
     * @param codeEnum
     * @return
     */
    public static JsonData buildResult(BizCodeEnum codeEnum){
        return JsonData.buildCodeAndMsg(codeEnum.getCode(),codeEnum.getMessage());
    }
}

自定义全局异常 处理器开发

/**
 * 全局异常处理
 */
@Data
public class BizException extends RuntimeException {

    private Integer code;
    private String msg;

    public BizException(Integer code, String message) {
        super(message);
        this.code = code;
        this.msg = message;
    }

    public BizException(BizCodeEnum bizCodeEnum) {
        super(bizCodeEnum.getMsg());
        this.code = bizCodeEnum.getCode();
        this.msg = bizCodeEnum.getMsg();
    }

}

@ControllerAdvice
@Slf4j
public class ExceptionHandle {

    /**
     * 自定义异常处理器
     */
    @ExceptionHandler(value = Exception.class)
    @ResponseBody
    public JsonData Handle(Exception e) {

        if (e instanceof BizException) {
            BizException bizException = (BizException) e;
            log.info("[业务异常]{}", e);
            return JsonData.buildError(bizException.getMsg(), bizException.getCode());

        } else {
            log.info("[系统异常]{}", e);
            return JsonData.buildError("全局异常，未知错误");
        }

    }
}

邮箱工具类正则

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("^((13[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();

    }
}

原文地址：http://www.cnblogs.com/youngleesin/p/16801327.html