future介绍

Future代表的是异步执行的结果意思是当异步执行结束之后返回的结果将会保存在Future中。 那么我们什么时候会用到Future呢 一般来说当我们执行一个长时间运行的任务时使用Future就可以让我们暂时去处理其他的任务等长任务执行完毕再返回其结果。

场景登录时获取用户ip地址插入登录日志需要获取用户ip对应的地理位置
接口

import cn.hutool.core.thread.ThreadUtil;
   @OpLog(title = "无密码登录", businessType = "用户登录")
    @GetMapping(value = "/secret-key/{secretKey}", produces = "application/json;charset=UTF-8")
    public Result<DiskUserSecretKeyLoginResponseDTO> secretKeyLogin(@PathVariable(name = "secretKey") String secretKey,
                                                                    HttpServletRequest request, HttpServletResponse response) throws IOException {

        if (SecurityUtils.getSubject().isAuthenticated()) {
            log.info("重复调用登陆模块");
            return getLoginInfo(request);
        }

        // 验证密钥是否为空
        if (StrUtil.isBlank(secretKey)) {
            return Result.refuse();
        }

        // 异步获取IP实际地理位置信息
        Future<Region> future = ThreadUtil.execAsync(() -> IpUtils.getIpLocationByBtree(ServletUtil.getClientIP(request)));

      ...后文省略
    }

ip工具类iputils:

import cn.hutool.core.lang.Singleton;
import org.lionsoul.ip2region.DataBlock;
import org.lionsoul.ip2region.DbConfig;
import org.lionsoul.ip2region.DbSearcher;
import org.apache.commons.io.IOUtils;
import cn.hutool.core.io.FileUtil;
import cn.hutool.core.net.NetUtil;
import cn.hutool.core.util.StrUtil;
    public static Region getIpLocationByBtree(String ip) {
        return getIpLocation(ip, "btreeSearch");
    }
 private static synchronized Region getIpLocation(String ip, String algorithm) {
        String intranetIp = "内网IP";
        if (StrUtil.isBlank(ip)) {
            log.info("The IP address detected is empty...");
            return new Region(intranetIp, intranetIp, intranetIp, intranetIp);
        } else if (isInnerIp(ip)) {
            return new Region(intranetIp, intranetIp, intranetIp, intranetIp);
        } else {
            try {
                DbConfig config = (DbConfig)Singleton.get(DbConfig.class, new Object[0]);
                File tempFile = FileUtil.touch((File)Singleton.get(File.class, new Object[]{"ip2region.db"}));
                InputStream inputStream = IpUtils.class.getClassLoader().getResourceAsStream("data/ip2region.db");
                FileOutputStream out = new FileOutputStream(tempFile);
                Throwable var7 = null;

                try {
                    if (inputStream != null) {
                        IOUtils.copy(inputStream, out);
                    }
                } catch (Throwable var17) {
                    var7 = var17;
                    throw var17;
                } finally {
                    if (out != null) {
                        if (var7 != null) {
                            try {
                                out.close();
                            } catch (Throwable var16) {
                                var7.addSuppressed(var16);
                            }
                        } else {
                            out.close();
                        }
                    }

                }

                DbSearcher dbSearcher = (DbSearcher)Singleton.get(DbSearcher.class, new Object[]{config, tempFile.getPath()});
                Method method = dbSearcher.getClass().getMethod(algorithm, String.class);
                DataBlock dataBlock = (DataBlock)method.invoke(dbSearcher, ip);
                if (dataBlock != null && StrUtil.isNotBlank(dataBlock.getRegion())) {
                    String[] ipData = dataBlock.getRegion().split("\\|");
                    return Region.builder().country(ipData[0]).province(ipData[2]).city(ipData[3]).isp(ipData[4]).build();
                } else {
                    return new Region(intranetIp, intranetIp, intranetIp, intranetIp);
                }
            } catch (Exception var19) {
                var19.printStackTrace();
                return new Region(intranetIp, intranetIp, intranetIp, intranetIp);
            }
        }
    }