springboot 配置拦截器

1 有这样一个需求

服务端对部分请求URL需要验证身份。如果验证错误，停止请求，按照既定的数据格式返回；如果验证正确，继续执行请求。

2 需要这样做

1. 将指定格式的请求拦截下来；

2. 获取参数，验证参数；

3. 验证不通过，返回既定数据格式。

3 步骤

　　需要对参数进行逻辑操作，所以需要在拦截器中注入实例，返回的数据是指定格式，所以要重写response

1.定义拦截器，要继承HandlerInterceptorAdapter ，重写“处理请求前”方法，在该方法中进行逻辑验证。

代码如下：

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

import com.boco.osmp.entities.TokenOriginEntity;
import com.boco.osmp.model.TokenModel;

import java.io.PrintWriter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 *
 *
 * @author
 *
 */
public class CommonInterceptor extends HandlerInterceptorAdapter {
    @Autowired
    private TokenModel tokenModel;

    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {

        String requestUri = request.getRequestURI();
        String contextPath = request.getContextPath();
        String url = requestUri.substring(contextPath.length());

        if ("GET".equalsIgnoreCase(request.getMethod()) || "POST".equalsIgnoreCase(request.getMethod())) {
            if (url.contains("/api/")) {
                String token = request.getHeader("authorization");
                String userId = request.getParameter("userId");
                if (token != null && userId != null) {
                    String tokenSource = tokenModel.getToken(userId);
                    // 如果token验证不通过，返回已经登录的用户信息
                    if (!token.equals(tokenSource)) {
                        String p = tokenModel.decryptTokenToResponse(tokenSource, TokenOriginEntity.class);
                        response.setContentType("application/json;charset=utf-8");
                        PrintWriter writer;
                        writer = response.getWriter();
                        writer.write(p);
                        return false;
                    }
                } else {
                    throw new Exception("token或 用户ID不能为空");
                }
            }
            return true;
        } else {
            throw new Exception("不支持的请求类型!");
        }

    }
    @Override
    public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,
            ModelAndView modelAndView) throws Exception {
        super.postHandle(request, response, handler, modelAndView);
    }
    @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)
            throws Exception {
        super.afterCompletion(request, response, handler, ex);
    }

    @Override
    public void afterConcurrentHandlingStarted(HttpServletRequest request, HttpServletResponse response, Object handler)
            throws Exception {
        super.afterConcurrentHandlingStarted(request, response, handler);
    }
}

拦截器中需要写的是，如果验证错误，需要返回既定格式数据，

是这几行代码实现的

 response.setContentType("application/json;charset=utf-8"); //JSON
                        PrintWriter writer;
                        writer = response.getWriter();
                        writer.write(p); //数据

2. 重写配置文件，添加新增的拦截器

在配置文件中需要实例化一个拦截器，这样才能保证在拦截器中注入的实例有效。

swagger U的默认地址也需要手动添加进去。

代码

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

import com.boco.osmp.interceptor.CommonInterceptor;

/**
 * 配置拦截器
 * 初始化拦截器，这样在拦截器中可以注入@service
 * @author
 */
@EnableWebMvc
@Configuration
public class WebMvcConfig extends WebMvcConfigurerAdapter {

    /**
     * 需要重新该方法，将swagger-ui.html手动加入，否则会请求不到
     */
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
        registry.addResourceHandler("swagger-ui.html")
                .addResourceLocations("classpath:/META-INF/resources/");

        registry.addResourceHandler("/webjars/**")
                .addResourceLocations("classpath:/META-INF/resources/webjars/");
    }

    @Bean
    public CommonInterceptor interceptor() {
        return new CommonInterceptor();
    }

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(interceptor()).addPathPatterns("/**");
        super.addInterceptors(registry);
    }
}