记录Threadlocal使用

编写ThreadLocal工具类

package com.jjking.jplan.context;public class BaseContext<T> {public static final ThreadLocal threadLocal = new ThreadLocal();//存储用户public static void set(Object t) {threadLocal.set(t);}//获取用户public static <T> T get() {return (T) threadLocal.get();}//移除用户public static void remove() {threadLocal.remove();}
}

搭配拦截器使用

package com.jjking.jplan.interceptors;import com.jjking.jplan.context.BaseContext;
import com.jjking.jplan.pojo.User;
import com.jjking.jplan.utils.JwtUtil;
import jakarta.servlet.http.HttpServletRequest;
import jakarta.servlet.http.HttpServletResponse;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;import java.util.Map;@Component
public class LoginInterceptors implements HandlerInterceptor {@Overridepublic boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {//获取tokenString token = request.getHeader("Authorization");try {//解析tokenMap<String, Object> clamis = JwtUtil.parseToken(token);//将当前信息装入ThreadLocalUser user = User.builder().id((Integer) clamis.get("id")).username((String) clamis.get("username")).build();BaseContext.set(user);return true;} catch (Exception e) {response.setStatus(401);//回去把孩子return false;}}@Overridepublic void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {//清空ThreadLoacl信息BaseContext.remove();}
}

我们在请求发送到服务器前,判断是否带着token,如果token解析正确,写入ThreadLocal

并且在请求完成之后,清空ThreadLocal

附录

jwt工具类

package com.jjking.jplan.utils;import com.auth0.jwt.JWT;
import com.auth0.jwt.algorithms.Algorithm;import java.util.Date;
import java.util.Map;public class JwtUtil {//秘钥private static final String KEY = "itheima";//接收业务数据,生成token并返回public static String genToken(Map<String, Object> claims) {return JWT.create().withClaim("claims", claims) //载荷.withExpiresAt(new Date(System.currentTimeMillis() + 1000 * 60 * 60 * 12)) //过期时间.sign(Algorithm.HMAC256(KEY));  //加密算法}//接收token,验证token,并返回业务数据public static Map<String, Object> parseToken(String token) {return JWT.require(Algorithm.HMAC256(KEY)).build().verify(token).getClaim("claims").asMap();}}

Md5工具类

package com.jjking.jplan.utils;import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;public class Md5Util {/*** 默认的密码字符串组合，用来将字节转换成 16 进制表示的字符,apache校验下载的文件的正确性用的就是默认的这个组合*/protected static char hexDigits[] = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};protected static MessageDigest messagedigest = null;static {try {messagedigest = MessageDigest.getInstance("MD5");} catch (NoSuchAlgorithmException nsaex) {System.err.println(Md5Util.class.getName() + "初始化失败，MessageDigest不支持MD5Util。");nsaex.printStackTrace();}}/*** 生成字符串的md5校验值** @param s* @return*/public static String getMD5String(String s) {return getMD5String(s.getBytes());}/*** 判断字符串的md5校验码是否与一个已知的md5码相匹配** @param password  要校验的字符串* @param md5PwdStr 已知的md5校验码* @return*/public static boolean checkPassword(String password, String md5PwdStr) {String s = getMD5String(password);return s.equals(md5PwdStr);}public static String getMD5String(byte[] bytes) {messagedigest.update(bytes);return bufferToHex(messagedigest.digest());}private static String bufferToHex(byte bytes[]) {return bufferToHex(bytes, 0, bytes.length);}private static String bufferToHex(byte bytes[], int m, int n) {StringBuffer stringbuffer = new StringBuffer(2 * n);int k = m + n;for (int l = m; l < k; l++) {appendHexPair(bytes[l], stringbuffer);}return stringbuffer.toString();}private static void appendHexPair(byte bt, StringBuffer stringbuffer) {char c0 = hexDigits[(bt & 0xf0) >> 4];// 取字节中高 4 位的数字转换, >>>// 为逻辑右移，将符号位一起右移,此处未发现两种符号有何不同char c1 = hexDigits[bt & 0xf];// 取字节中低 4 位的数字转换stringbuffer.append(c0);stringbuffer.append(c1);}}