这是app后台框架搭建的第二课，主要针对app应用是跨域的运用，讲解怎么配置跨域服务；其次讲解怎么进行token验证，通过拦截器设置token验证和把token设置到http报文中。主要有如下：
1）app后台跨域设置
2）拦截器中设置http报文header中token
3）token的生成实现
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1，app后台跨域的设置
1.1 springmvc4 有直接在请求映射中对跨域的处理，只需加一个@CrossOrign()
@CrossOrigin(origins = "http://localhost:9000")
@GetMapping("/greeting")
public Greeting greeting(@RequestParam(required=false, defaultValue="World") String name) {
System.out.println("==== in greeting ====");
return new Greeting(counter.incrementAndGet(), String.format(template, name));
}对全局请求路径的拦截的，则需要在配置类里声明：
@Bean
public WebMvcConfigurer corsConfigurer() {
return new WebMvcConfigurerAdapter() {
@Override
public void addCorsMappings(CorsRegistry registry) {
registry.addMapping("/greeting-javaconfig").allowedOrigins("http://localhost:9000");
}
};
}“/greeting-javaconfig” 则是你定义的请求路径了，你也可以直接设置为 /api/* 之类的，allowedOrigins也可以匹配成 *
可以参考官方文档：https://spring.io/guides/gs/rest-service-cors/
1.2 通过filter过滤器进行处理
其实，spring的拦截器也是可以处理跨域的问题，但对于post+json的支持不是很好，用拦截器的支持会好一些：
首先，定义拦截器：
public class CrossFilter extends OncePerRequestFilter {
@Override
protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain) throws ServletException, IOException {
if (request.getHeader("Access-Control-Request-Method") != null && "OPTIONS".equals(request.getMethod())) {
// CORS "pre-flight" request
response.addHeader("Access-Control-Allow-Origin", "*");
response.addHeader("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE");
response.addHeader("Access-Control-Allow-Headers", "Content-Type");
response.addHeader("Access-Control-Max-Age", "1800");//30 min
}
filterChain.doFilter(request, response);
}
}其次，在web.xml设置过滤：
<filter>
<filter-name>cors</filter-name>
<filter-class>cn.***.filter.CrossFilter</filter-class>
</filter>
<filter-mapping>
<filter-name>cors</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>当然spring4 appalication.xml 也可以配置成：
<mvc:cors>
<mvc:mapping path="/**" allowed-origins="*" allow-credentials="true" max-age="1800" allowed-methods="GET,POST,OPTIONS"/>
</mvc:cors>3）我的配置类配置：
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.*;
import org.springframework.core.env.Environment;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.cors.UrlBasedCorsConfigurationSource;
import org.springframework.web.filter.CorsFilter;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.*;
import org.springframework.web.servlet.mvc.Controller;
import org.springframework.web.servlet.view.InternalResourceViewResolver;
import java.util.ArrayList;
import java.util.List;
/**
* Created by ThinkPad on 2017/6/15.
*/
@Configuration
@EnableWebMvc
@ComponentScan(basePackages = {"com.ouyang.teson"},useDefaultFilters = true)
@PropertySource({"classpath:teson.properties"})
public class WebConfig extends WebMvcConfigurerAdapter{
private final static Logger logger = LoggerFactory.getLogger(WebConfig.class);
public ViewResolver viewResolver() {
InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
viewResolver.setPrefix("/WEB-INF/views/jsp/function/");
viewResolver.setSuffix(".jsp");
return viewResolver;
}
//静态文件
@Override
public void addResourceHandlers(ResourceHandlerRegistry registry) {
logger.info("addResourceHandlers");
registry.addResourceHandler("/static/**").addResourceLocations("/WEB-INF/static/");
}
//允许跨域的接口
@Override
public void addCorsMappings(CorsRegistry registry) {
registry.addMapping("/api/*").allowedOrigins("*")
.allowCredentials(false)
.allowedMethods("GET", "POST", "DELETE", "PUT")
.allowedHeaders("Access-Control-Allow-Origin","Access-Control-Allow-Headers","Access-Control-Allow-Methods"
,"Access-Control-Max-Age")
.exposedHeaders("Access-Control-Allow-Origin")
.maxAge(3600);
}
}2) 在拦截器中设置token
在拦截器中设置token这个比较简单，我就直接带过了，看配置：
拦截器类：HeaderTokenInterceptor.java
package com.ouyang.teson.intercept;
import com.ouyang.teson.WebConfig;
import com.ouyang.teson.util.JwtUtil;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.PrintWriter;
/**
* Created by ThinkPad on 2017/6/20.
*/
public class HeaderTokenInterceptor implements HandlerInterceptor {
private final static Logger logger = LoggerFactory.getLogger(HeaderTokenInterceptor.class);
@Autowired
JwtUtil jwtUtil;
@Override
public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
// String contentPath=httpServletRequest.getContextPath();
// System.out.println("contenxPath:"+contentPath);
String requestURI=httpServletRequest.getRequestURI();
String tokenStr=httpServletRequest.getParameter("token");
String token="";
if(requestURI.contains("/api/")){
token=httpServletRequest.getHeader("token");
if(token==null && tokenStr==null){
System.out.println("real token:======================is null");
String str="{'errorCode':801,'message':'缺少token，无法验证','data':null}";
dealErrorReturn(httpServletRequest,httpServletResponse,str);
return false;
}
if(tokenStr!=null){
token=tokenStr;
}
token=jwtUtil.updateToken(token);
System.out.println("real token:=============================="+token);
System.out.println("real ohter:=============================="+httpServletRequest.getHeader("Cookie"));
}
httpServletResponse.setHeader("token",token);
/* httpServletResponse.setHeader("Access-Control-Allow-Origin", "*");
httpServletResponse.setHeader("Access-Control-Allow-Headers", "Content-Type, Authorization");
httpServletResponse.setHeader("Access-Control-Allow-Methods", "POST, GET, OPTIONS, PUT");*/
return true;
}
@Override
public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
}
@Override
public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
}
// 检测到没有token，直接返回不验证
public void dealErrorReturn(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse,Object obj){
String json = (String)obj;
PrintWriter writer = null;
httpServletResponse.setCharacterEncoding("UTF-8");
httpServletResponse.setContentType("text/html; charset=utf-8");
try {
writer = httpServletResponse.getWriter();
writer.print(json);
} catch (IOException ex) {
logger.error("response error",ex);
} finally {
if (writer != null)
writer.close();
}
}
}httpServletResponse.setHeader("token",token)是设置返回response的header的token信息，每一次拦截的时候，会查看是否有token，如果没有就直接报错
关于app 后台返回的结果，在实际的开发中需要统一返回数据格式，这个会在下一节中讲到。在webconfig.java 类中添加以下两个方法：
@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(getTokenHeader())
.addPathPatterns("/api/*")
.excludePathPatterns(
"/robots.txt");
}
//token 在header的拦截器
@Bean
public HandlerInterceptor getTokenHeader(){
return new HeaderTokenInterceptor();
}3） token的实现
token的实现使用jwt组件生成token，如果想要自己通过md5，或者rsa加密生成token也比较简便了，只是这个token要缓存起来，每次进行验证，验证完更新token。更新token主要是更新token里包含的时间，防止token过期。如果使用token的话，可以不用存放缓存，对于登陆验证成功后，我们会生成token，这个token还能带有用户的id等基本信息，我们就可以验证他的过期时间，id等信息。
关于jwt 组件的介绍，可以去看看我的 java组件的jwt的介绍。
直接进入主题了：
maven需要导入
<!-- java-web-token 验证授权-->
<dependency>
<groupId>com.auth0</groupId>
<artifactId>java-jwt</artifactId>
<version>3.2.0</version>
</dependency>
<!-- https://mvnrepository.com/artifact/io.jsonwebtoken/jjwt -->
<dependency>
<groupId>io.jsonwebtoken</groupId>
<artifactId>jjwt</artifactId>
<version>0.7.0</version>
</dependency>jjwt 主要是对jwt进一步封装，可以快速开发web的token认证。
jwt工具类：jwtUtil.java
package com.ouyang.teson.util;
import io.jsonwebtoken.Claims;
import io.jsonwebtoken.JwtBuilder;
import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;
import javax.crypto.spec.SecretKeySpec;
import javax.xml.bind.DatatypeConverter;
import java.security.Key;
import java.util.Date;
/**
* Created by ThinkPad on 2017/6/17.
*/
@Component
public class JwtUtil {
public static String sercetKey="mingtianhenganghao";
public final static long keeptime=1800000;
/* @Value("${token.sercetKey}")
public static String sercetKey;
@Value("${token.keeptime:30000}")
public static long keeptime;*/
public static String generToken(String id, String issuer, String subject){
long ttlMillis=keeptime;
SignatureAlgorithm signatureAlgorithm = SignatureAlgorithm.HS256;
long nowMillis = System.currentTimeMillis();
Date now = new Date(nowMillis);
byte[] apiKeySecretBytes = DatatypeConverter.parseBase64Binary(sercetKey);
Key signingKey = new SecretKeySpec(apiKeySecretBytes, signatureAlgorithm.getJcaName());
JwtBuilder builder = Jwts.builder().setId(id)
.setIssuedAt(now);
if(subject!=null){
builder.setSubject(subject);
}
if(issuer!=null){
builder.setIssuer(issuer);
}
builder .signWith(signatureAlgorithm, signingKey);
if (ttlMillis >= 0) {
long expMillis = nowMillis + ttlMillis;
Date exp = new Date(expMillis);
builder.setExpiration(exp);
}
return builder.compact();
}
public String updateToken(String token){
try {
Claims claims=verifyToken(token);
String id=claims.getId();
String subject=claims.getSubject();
String issuer=claims.getIssuer();
Date date = claims.getExpiration();
return generToken(id, issuer, subject);
}catch (Exception ex){
ex.printStackTrace();
}
return "0";
}
public String updateTokenBase64Code(String token) {
BASE64Encoder base64Encoder=new BASE64Encoder();
BASE64Decoder decoder = new BASE64Decoder();
try {
token=new String(decoder.decodeBuffer(token),"utf-8");
Claims claims=verifyToken(token);
String id=claims.getId();
String subject=claims.getSubject();
String issuer=claims.getIssuer();
Date date = claims.getExpiration();
String newToken = generToken(id, issuer, subject);
return base64Encoder.encode(newToken.getBytes());
}catch (Exception ex){
ex.printStackTrace();
}
return "0";
}
public static Claims verifyToken(String token){
Claims claims = Jwts.parser()
.setSigningKey(DatatypeConverter.parseBase64Binary(sercetKey))
.parseClaimsJws(token).getBody();
return claims;
}
}关于拦截器的处理token，及更新token，上面已经给出代码，这里不再列出。来看一下简单的控制类，仅供学习，如果要运用到生产环境还得各种配置和测试。
登陆的控制方法：
@RequestMapping("/login")
public String login(String name,String password, Model model){
if(name==null || password==null){
return "error";
}
String token = jwtUtil.generToken("xiaoming",null,null);
model.addAttribute("token", token);
return "redirect:/api/liu";
}这里没有做验证，只是简单根据账户密码，生成token后，重定向；接下来的任务就交给拦截器了，拦截器会拦截/api/* 下的请求，然后请求参数有token的会验证token，并更新token，并把token放到header里。
这里可以看到token字符串有两个点，最好把jwt生成的token进行base64位编码，jwtUtil.java里有updateTokenBase64Code(String token)就是处理token进行base64位编码的。处理速度还是蛮快的。
最后，app后台框架的代码会在第五讲左右，把代码放出来。没有那么充足时间，写博客。
