HandlerInterceptor简介
拦截器我想大家都并不陌生，最常用的登录拦截、或是权限校验、或是防重复提交、或是根据业务像12306去校验购票时间,总之可以去做很多的事情。
我仔细想了想
这里我分三篇博客来介绍HandlerInterceptor的使用，从基本的使用、到自定义注解、最后到读取body中的流解决无法多次读取的问题。
1、定义实现类
定义一个Interceptor 非常简单方式也有几种，这里简单列举两种
1、类要实现Spring 的HandlerInterceptor 接口
2、类继承已经实现了HandlerInterceptor 接口的类，例如 已经提供的实现了HandlerInterceptor 接口的抽象类HandlerInterceptorAdapter
2、HandlerInterceptor方法介绍
boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
throws Exception;
void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
ModelAndView modelAndView) throws Exception;
void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object
handler, Exception ex) throws Exception;
- preHandle：在业务处理器处理请求之前被调用。预处理，可以进行编码、安全控制、权限校验等处理；
- postHandle：在业务处理器处理请求执行完成后，生成视图之前执行。后处理（调用了Service并返回ModelAndView，但未进行页面渲染），有机会修改ModelAndView （这个博主就基本不怎么用了）；
- afterCompletion：在DispatcherServlet完全处理完请求后被调用，可用于清理资源等。返回处理（已经渲染了页面）；
接下来让我们来实现一个登陆 and 访问权限校验的拦截器吧
2.1 新建LoginInterceptor
@Slf4j
public class LoginInterceptor implements HandlerInterceptor {
public static ThreadLocal<LoginUser> threadLocal = new ThreadLocal<>();
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
if (HttpMethod.OPTIONS.toString().equalsIgnoreCase(request.getMethod())) {
response.setStatus(HttpStatus.NO_CONTENT.value());
return true;
}
String accessToken = request.getHeader("token");
if (StringUtils.isBlank(accessToken)) {
accessToken = request.getParameter("token");
}
if (StringUtils.isNotBlank(accessToken)) {
Claims claims = JWTUtil.checkJWT(accessToken);
if (claims == null) {
//未登录
CommonUtil.sendJsonMessage(response, JsonData.buildResult(BizCodeEnum.ACCOUNT_UNLOGIN));
return false;
}
Long accountNo = Long.parseLong(claims.get("account_no").toString());
String headImg = (String) claims.get("head_img");
String username = (String) claims.get("username");
String mail = (String) claims.get("mail");
String phone = (String) claims.get("phone");
String auth = (String) claims.get("auth");
LoginUser loginUser = LoginUser.builder()
.accountNo(accountNo)
.auth(auth)
.phone(phone)
.headImg(headImg)
.mail(mail)
.username(username)
.build();
//request.setAttribute("loginUser",loginUser);
//通过threadlocal
threadLocal.set(loginUser);
return true;
}
return false;
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
threadLocal.remove();
}
}- jwt加密、解密工具类：
@Slf4j
public class JWTUtil {
/**
* 主题
*/
private static final String SUBJECT = "abclass";
/**
* 加密密钥
*/
private static final String SECRET = "abclass.net168";
/**
* 令牌前缀
*/
private static final String TOKNE_PREFIX = "abclass-link";
/**
* token过期时间，7天
*/
private static final long EXPIRED = 1000 * 60 * 60 * 24 * 7;
/**
* 生成token
*
* @param loginUser
* @return
*/
public static String geneJsonWebTokne(LoginUser loginUser) {
if (loginUser == null) {
throw new NullPointerException("对象为空");
}
String token = Jwts.builder().setSubject(SUBJECT)
//配置payload
.claim("head_img", loginUser.getHeadImg())
.claim("account_no", loginUser.getAccountNo())
.claim("username", loginUser.getUsername())
.claim("mail", loginUser.getMail())
.claim("phone", loginUser.getPhone())
.claim("auth", loginUser.getAuth())
.setIssuedAt(new Date())
.setExpiration(new Date(CommonUtil.getCurrentTimestamp() + EXPIRED))
.signWith(SignatureAlgorithm.HS256, SECRET).compact();
token = TOKNE_PREFIX + token;
return token;
}
/**
* 解密jwt
* @param token
* @return
*/
public static Claims checkJWT(String token) {
try {
final Claims claims = Jwts.parser().setSigningKey(SECRET)
.parseClaimsJws(token.replace(TOKNE_PREFIX, "")).getBody();
return claims;
} catch (Exception e) {
log.error("jwt 解密失败");
return null;
}
}
}- 工具类
@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;
}
/**
* 获取全部请求头
*
* @param request
* @return
*/
public static Map<String, String> getAllRequestHeader(HttpServletRequest request) {
Enumeration<String> headerNames = request.getHeaderNames();
Map<String, String> map = new HashMap<>();
while (headerNames.hasMoreElements()) {
String key = (String) headerNames.nextElement();
//根据名称获取请求头的值
String value = request.getHeader(key);
map.put(key, value);
}
return map;
}
/**
* MD5加密
*
* @param data
* @return
*/
public static String MD5(String data) {
try {
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) {
//生成随机数字和字母,
Random random = new Random();
StringBuilder saltString = new StringBuilder(length);
for (int i = 1; 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) {
response.setContentType("application/json; charset=utf-8");
try (PrintWriter writer = response.getWriter()) {
writer.print(JsonUtil.obj2Json(obj));
response.flushBuffer();
} catch (IOException e) {
log.warn("响应json数据给前端异常:{}", e);
}
}
}- 登录登录用户
@Data
@Builder
@AllArgsConstructor
@NoArgsConstructor
public class LoginUser {
/** 账号*/
private long accountNo;
/** 用户名 */
private String username;
/** 头像 */
private String headImg;
/** 邮箱 */
private String mail;
/** 手机号 */
private String phone;
/** 认证级别 */
private String auth;
}2.2 新建WebAppConfigurer 实现WebMvcConfigurer接口
其实以前都是继承WebMvcConfigurerAdapter类 不过springBoot2.0以上 WebMvcConfigurerAdapter 方法过时，有两种替代方案：
1、继承WebMvcConfigurationSupport
2、实现WebMvcConfigurer
但是继承WebMvcConfigurationSupport会让Spring-boot对mvc的自动配置失效。根据项目情况选择。现在大多数项目是前后端分离，并没有对静态资源有自动配置的需求所以继承WebMvcConfigurationSupport也未尝不可。
@Configuration
@Slf4j
public class InterceptorConfig implements WebMvcConfigurer {
@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(new LoginInterceptor())
//添加拦截的路径
.addPathPatterns("/api/account/*/**", "/api/traffic/*/**")
//排除不拦截
.excludePathPatterns(
"/api/account/*/register","/api/account/*/upload","/api/account/*/login",
"/api/notify/v1/captcha","/api/notify/*/send_code");
}
}是否感觉配置这个地址是不特别方便？下一篇博客介绍2.0版本引入注解来协助完成一系列的拦截任务。
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