PS:作者是小白能接触到的就只会这样写。勿喷。

前提

思路: 结合io流将登录token存储到配置文件中,不将token存储到浏览器端，从而避免盗取。

下面jwt的学习可以参考下这个:

JWT --- 入门学习_本郡主是喵的博客-CSDN博客

JWT工具类

@Component
public class JWTtUtils {public static final String USER_NAME = "username";public static final String PASS_WORD = "password";public static final String CREATE_TIME = "createTime";public static final String SIGN_KEY = "QHX2004"; // 解析key/*** 用用户名和密码生成JWT** @param username* @param password* @return*/public String generatorJWTFromUserNameAndPassword(String username,String password){HashMap<String, Object> hashMap = new HashMap<>(); // 生成maphashMap.put(USER_NAME,username);hashMap.put(PASS_WORD,password);hashMap.put(CREATE_TIME,new Date());return  generatorJWTFromUserNameAndPassword(hashMap);}/*** 生成jwt过期时间,1个月** @param* @return*/private Date generatorExpirationDate() {return new Date(System.currentTimeMillis() + (1000L * 60 * 60 *24 *30));}/*** 用用户名和密码生成jwt** @param paramMap* @return*/private String generatorJWTFromUserNameAndPassword(HashMap<String, Object> paramMap) {JwtBuilder jwtBuilder = Jwts.builder().setClaims(paramMap).setExpiration(generatorExpirationDate()) // 设置过期时间.signWith(SignatureAlgorithm.HS512,SIGN_KEY);return jwtBuilder.compact(); // 拿到token}/*** 解析token拿到Claims*** @param token* @return*/private Claims getClaimsFromToken(String token){Claims claims = Jwts.parser().setSigningKey(SIGN_KEY).parseClaimsJws(token).getBody();return claims;}/*** 校验token是否过期** @param token* @return*/// 过期返回truepublic boolean checkTokenIsOverdue(String token){Claims claims = getClaimsFromToken(token);Date date =  claims.getExpiration();return date.getTime() < new Date().getTime();}/*** 刷新token:重新生成一个token** @param* @return*/public String flushToken(String token){Claims claims = getClaimsFromToken(token);String username = (String) claims.get(USER_NAME);String password = (String)claims.get(PASS_WORD);return generatorJWTFromUserNameAndPassword(username,password);}}

IO工具类

public class IOUtils {public static final String FILE_NAME = "conf.properties";/***   配置文件读取* @param key* @return  value*/public static String getPropertiesKey(String key)  {return  getKey(key);}/*** 配置文件读取** @param  key* @return*/private static String getKey(String key) {Properties properties = new Properties();File file = new File(FILE_NAME);FileInputStream inputStream = null;try {inputStream = new FileInputStream(file);properties.load(inputStream); // 其实已经将配置文件拿到手了} catch (IOException e) {e.printStackTrace();}finally {if(inputStream != null){  // 还是这样关比较好，万一报错就tm关不了try {inputStream.close();} catch (IOException e) {e.printStackTrace();}}}return  properties.getProperty(key);}/*** 配置文件设置** @param key* @param value* @return*/public static boolean setPropertiesKey(String key,String value) {// 判断key是否有重复String key1 = getKey(key);if(key1 == null){return setKey(key,value); // 把核心业务逻辑抽出来}return false;}/***  配置文件设置** @param key* @param value* @return boolean*/private static boolean setKey(String key, String value) {Properties properties = new Properties();File file = new File(FILE_NAME); // 其实有其他配置可以同意下yaml文件里面配置，然后这里面读取，好统一调配。FileWriter fileWriter = null;try {fileWriter = new FileWriter(file,true);properties.setProperty(key, value); // 存进map里面properties.store(fileWriter,""); // 将map对应的键值对写进输出流。} catch (IOException e) {// 卧槽我加入设置key,value失败，肯定调到这个逻辑return false;} finally {if (fileWriter != null) {  // 还是这样关比较好，万一报错就tm关不了try {fileWriter.flush();fileWriter.close();} catch (IOException e) {e.printStackTrace();}}}return true;}}

测试文件

@SpringBootTest
class IoDemoApplicationTests {@Testvoid contextLoads() {// 用户第一登录 ----,我们这里浏览器端不存token，只存用户名,更安全。String username = "qhx2005";String password = "123456";// 生成jwtJWTtUtils jwTtUtils = new JWTtUtils();String token = jwTtUtils.generatorJWTFromUserNameAndPassword(username, password);// 将jwt存进配置文件boolean success = IOUtils.setPropertiesKey(username, token);System.out.println("存进配置文件成功状态:"+success);assert success;// 用户登录后访问其他页面。检验token过期，拿出配置文件是否存在----// 获取tokenString token1 = IOUtils.getPropertiesKey(username);System.out.println(token1);// 检验token是否过期boolean overdue = jwTtUtils.checkTokenIsOverdue(token);// 本来这里如果token过期,我们响应一个状态码，让前端axios过滤器捕获到，删除本地username,重定向到登录页。System.out.println("已经过期:"+overdue);}}