Java小功能

序列号生成
Java
发布日期:   2025-05-28
文章字数:   1.3k
阅读时长:   7 分
阅读次数:  

Java工具类

1、生成序号的工具类

package com.ly.business.sport.utils;
import java.text.SimpleDateFormat;
import java.util.Date;

/**
 * @description: 自动生成单号工具类 格式 : yyyyMMdd0001，每日从0001开始自增长
 */
public class GenerateOddNumbersUtil {
    /**
     * @param maxOddNumbers  数据库中的最新单号
     * @return java.lang.String
     */
    public static String getOddNumbers(String maxOddNumbers){
        //定义变量(最新的单号)
        String newOddNumber = "";
        //获取当前日期并将其进行格式化
        SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyyMMdd");
        String formatDate = simpleDateFormat.format(new Date());
        //判断数据中的最大单号是否存在，是否包含当前日期
        if (maxOddNumbers != null && maxOddNumbers.contains(formatDate)){
            //截取后四位数
            String endNum = maxOddNumbers.substring(8);
            //把截取的最后四位数解析为int
            int endIntNum = Integer.parseInt(endNum);
            //在将其加1(自增1)
            int newEndIntNum = 10000+endIntNum+1;
            //把10000的1去掉，获取到最新的后四位
            String newEndNum = String.valueOf(newEndIntNum).substring(1);
            //生成单号
            newOddNumber = formatDate+newEndNum;
            //将单号返回
            return newOddNumber;
        }else{
            //如果为空(第一次生成)或者当前最大订单号的日期与当前日期不一致说明需要重新计数生成单号
            newOddNumber = formatDate+"0001";
            //将单号返回
            return newOddNumber;
        }
    }
}
<select id="getcode" resultType="map" parameterType="map">
       SELECT MAX(ydybh) odd_numbers FROM athlete
 </select>

测试代码：

Map map=projectService.getcode(params);
String ydybh= GenerateOddNumbersUtil.getOddNumbers( map.get("odd_numbers").toString());
params.put("ydybh", ydybh);

2、http请求数据工具类(OkHttpClient)

HttpUtils:

import com.squareup.moshi.JsonAdapter;
import com.squareup.moshi.Moshi;
import okhttp3.*;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.io.IOException;
import java.util.List;
import java.util.Map;

public class HttpUtils {


    private static final Moshi moshi = new Moshi.Builder().build(); // json utll
    private static final JsonAdapter<Map> mapAdapter = moshi.adapter(Map.class);
    private static final JsonAdapter<List> listAdapter = moshi.adapter(List.class);
    private final Logger logger = LoggerFactory.getLogger(this.getClass());
    public static final MediaType JSON = MediaType.parse("application/json; charset=utf-8");

    public static Response post(OkHttpClient client, String url, Map params) throws IOException {
        RequestBody reqbody = RequestBody.create(JSON, mapAdapter.toJson(params));
        Request request = new Request.Builder()
                .url(url)
                .addHeader("Accept", "application/json, text/javascript, */*; q=0.01")
                .addHeader("x-requested-with", "XMLHttpRequest")
                .addHeader("Accept-Language", "zh-CN,zh;q=0.9")
                .addHeader("Accept-Encoding", "gzip, deflate")
                .post(reqbody)
                .build();
        Response response = client.newCall(request).execute();
        if (!response.isSuccessful()) {
            throw new IOException("Unexpected code " + response);
        }
        return response;
    }


    public static Response post(OkHttpClient client, String url, Map<String, String> header, Map params) throws IOException {
        RequestBody reqbody = RequestBody.create(JSON, mapAdapter.toJson(params));
        Request.Builder builderHeader = new Request.Builder();
        header.forEach((k, v) -> {
            builderHeader.addHeader(k, v);
        });
        builderHeader.addHeader("Accept", "application/json, text/javascript, */*; q=0.01")
                .addHeader("x-requested-with", "XMLHttpRequest")
                .addHeader("Accept-Language", "zh-CN,zh;q=0.9")
                .addHeader("Accept-Encoding", "gzip, deflate");
        Request request = builderHeader.url(url).post(reqbody).build();
        Response response = client.newCall(request).execute();
        if (!response.isSuccessful()) {
            throw new IOException("Unexpected code " + response);
        }
        return response;
    }

    public static Response get(OkHttpClient client, String url, String cookie) throws IOException {
        HttpUrl parse = HttpUrl.parse(url);
        HttpUrl.Builder httpBuider = parse.newBuilder();
        Request request = new Request.Builder().url(httpBuider.build()).addHeader("Cookie", cookie).build();
        Response response = client.newCall(request).execute();
        if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);
        return response;
    }

    public static Response get(OkHttpClient client, String url) throws IOException {
        HttpUrl parse = HttpUrl.parse(url);
        HttpUrl.Builder httpBuider = parse.newBuilder();
        Request request = new Request.Builder().url(httpBuider.build()).build();
        Response response = client.newCall(request).execute();
        if (!response.isSuccessful()) throw new IOException("Unexpected code " + response);
        return response;
    }

}

具体调用：

public Map test() throws IOException {
     String cookie = "tk=\"eQc7DvlmiOUV41Nrvxlg8eZNBWN93fTcVYgsigh55VEdCObVgqOfSg==\"";
     String URL = "http://xxxxxx";
     Map params = new HashMap();
     String json = "{\"area\":\"\"}";
     params = mapAdapter.fromJson(json);
     OkHttpClient client = new OkHttpClient().newBuilder().build();
     Map header = new HashMap<>();
     header.put("Cookie", cookie);
     header.put("systemCode", "MENU200136");
     Response post = HttpUtils.post(client, URL, header, params);
     return mapAdapter.fromJson(post.body().string());
 }

3、一个注解搞定 SpringBoot 接口防刷

一，技术要点：springboot的基本知识，redis基本操作

首先是写一个注解类：

import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import static java.lang.annotation.ElementType.METHOD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

@Retention(RUNTIME)
@Target(METHOD)
public @interface AccessLimit {

    int seconds();
    int maxCount();
    boolean needLogin()default true;
}

接着就是在Interceptor拦截器中实现：

import com.alibaba.fastjson.JSON;
import com.example.demo.action.AccessLimit;
import com.example.demo.redis.RedisService;
import com.example.demo.result.CodeMsg;
import com.example.demo.result.Result;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;
 
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.OutputStream;
 
@Component
public class FangshuaInterceptor extends HandlerInterceptorAdapter {
 
    @Autowired
    private RedisService redisService;
 
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
 
        //判断请求是否属于方法的请求
        if(handler instanceof HandlerMethod){
 
            HandlerMethod hm = (HandlerMethod) handler;
 
            //获取方法中的注解,看是否有该注解
            AccessLimit accessLimit = hm.getMethodAnnotation(AccessLimit.class);
            if(accessLimit == null){
                return true;
            }
            int seconds = accessLimit.seconds();
            int maxCount = accessLimit.maxCount();
            boolean login = accessLimit.needLogin();
            String key = request.getRequestURI();
            //如果需要登录
            if(login){
                //获取登录的session进行判断
                //.....
                key+=""+"1";  //这里假设用户是1,项目中是动态获取的userId
            }
 
            //从redis中获取用户访问的次数
            AccessKey ak = AccessKey.withExpire(seconds);
            Integer count = redisService.get(ak,key,Integer.class);
            if(count == null){
                //第一次访问
                redisService.set(ak,key,1);
            }else if(count < maxCount){
                //加1
                redisService.incr(ak,key);
            }else{
                //超出访问次数
                render(response,CodeMsg.ACCESS_LIMIT_REACHED); //这里的CodeMsg是一个返回参数
                return false;
            }
        }
 
        return true;
 
    }
    private void render(HttpServletResponse response, CodeMsg cm)throws Exception {
        response.setContentType("application/json;charset=UTF-8");
        OutputStream out = response.getOutputStream();
        String str  = JSON.toJSONString(Result.error(cm));
        out.write(str.getBytes("UTF-8"));
        out.flush();
        out.close();
    }
}

再把Interceptor注册到springboot中

import com.example.demo.ExceptionHander.FangshuaInterceptor;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

@Configuration
public class WebConfig extends WebMvcConfigurerAdapter {
 
    @Autowired
    private FangshuaInterceptor interceptor;
 
 
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(interceptor);
    }
}

接着在Controller中加入注解

import com.example.demo.result.Result;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
 
@Controller
public class FangshuaController {
 
    @AccessLimit(seconds=5, maxCount=5, needLogin=true)
    @RequestMapping("/fangshua")
    @ResponseBody
    public Result<String> fangshua(){
 
 
        return Result.success("请求成功");
 
    }
文章作者: Liu Yuan
文章链接: https://blog.ymxl.me/post/javaTips.html
版权声明: 本博客所有文章除特別声明外，均采用 CC BY 4.0 许可协议。转载请注明来源 Liu Yuan !
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