详解前后端分离之Java后端

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.5.2.RELEASE</version>
    <relativePath /> <!-- lookup parent from repository -->
  </parent>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
    <java.version>1.8</java.version>
  </properties>

  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <!-- JJWT -->
    <dependency>
      <groupId>io.jsonwebtoken</groupId>
      <artifactId>jjwt</artifactId>
      <version>0.6.0</version>
    </dependency>

    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-devtools</artifactId>
      <optional>true</optional>
    </dependency>

    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-test</artifactId>
      <scope>test</scope>
    </dependency>
  </dependencies>

import java.util.Date;

import javax.servlet.ServletException;

import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.RestController;

import io.jsonwebtoken.Jwts;
import io.jsonwebtoken.SignatureAlgorithm;

@RestController
@RequestMapping("/")
public class HomeController {

  @PostMapping("/login")
  public String login(@RequestParam("username") String name, @RequestParam("password") String pass)
      throws ServletException {
    String token = "";
    if (!"admin".equals(name)) {
      throw new ServletException("找不到该用户");
    }
    if (!"1234".equals(pass)) {
      throw new ServletException("密码错误");
    }
    token = Jwts.builder().setSubject(name).claim("roles", "user").setIssuedAt(new Date())
        .signWith(SignatureAlgorithm.HS256, "base64EncodedSecretKey").compact();
    return token;
  }
}

public class JwtFilter extends GenericFilterBean {

  @Override
  public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain)
      throws IOException, ServletException {
    HttpServletRequest request = (HttpServletRequest) req;
    HttpServletResponse response = (HttpServletResponse) res;
    String authHeader = request.getHeader("Authorization");
    if ("OPTIONS".equals(request.getMethod())) {
      response.setStatus(HttpServletResponse.SC_OK);
      chain.doFilter(req, res);
    } else {
      if (authHeader == null || !authHeader.startsWith("Bearer ")) {
        throw new ServletException("不合法的Authorization header");
      }
      // 取得token
      String token = authHeader.substring(7);
      try {
        Claims claims = Jwts.parser().setSigningKey("base64EncodedSecretKey").parseClaimsJws(token).getBody();
        request.setAttribute("claims", claims);
      } catch (Exception e) {
        throw new ServletException("Invalid Token");
      }
      chain.doFilter(req, res);
    }
  }

}

@SpringBootApplication
public class AuthServerApplication {

  @Bean
  public FilterRegistrationBean jwtFilter() {
    FilterRegistrationBean rbean = new FilterRegistrationBean();
    rbean.setFilter(new JwtFilter());
    rbean.addUrlPatterns("/user/*");// 过滤user下的链接
    return rbean;
  }

  public static void main(String[] args) {
    SpringApplication.run(AuthServerApplication.class, args);
  }
}

@RestController
@RequestMapping("/user")
public class UserController {

  @GetMapping("/success")
  public String success() {
    return "恭喜您登录成功";
  }

  @GetMapping("/getEmail")
  public String getEmail() {
    return "xxxx@qq.com";
  }
}

@Configuration
public class CorsConfig {

  @Bean
  public FilterRegistrationBean corsFilter() {
    UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
    CorsConfiguration config = new CorsConfiguration();
    config.setAllowCredentials(true);
    config.addAllowedOrigin("*");
    config.addAllowedHeader("*");
    config.addAllowedMethod("OPTION");
    config.addAllowedMethod("GET");
    config.addAllowedMethod("POST");
    config.addAllowedMethod("PUT");
    config.addAllowedMethod("HEAD");
    config.addAllowedMethod("DELETE");
    source.registerCorsConfiguration("/**", config);
    FilterRegistrationBean bean = new FilterRegistrationBean(new CorsFilter(source));
    bean.setOrder(0);
    return bean;
  }

  @Bean
  public WebMvcConfigurer mvcConfigurer() {
    return new WebMvcConfigurerAdapter() {
      @Override
      public void addCorsMappings(CorsRegistry registry) {
        registry.addMapping("/**").allowedMethods("GET", "PUT", "POST", "GET", "OPTIONS");
      }
    };
  }
}