springboot 请求拦截器---含后端解决前端跨域问题
拦截器参考: https://www.jianshu.com/p/e52444f0a121
跨域参考: https://www.cnblogs.com/yuansc/p/9076604.html
创建一个Config来注册拦截器，代码如下：
MyMvcConfig -----这个意义是 让配置的一些接口，不需要走拦截器的逻辑
package com.config;
import com.controle.lanjie.LoginHandlerInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
@Configuration
public class MyMvcConfig implements WebMvcConfigurer {
//所有的WebMvcConfigurerAdapter组件都会一起起作用
@Bean //将组件注册在容器中
public WebMvcConfigurer webMvcConfigurerAdapter(){
return new WebMvcConfigurer(){
//注册拦截器
@Override
public void addInterceptors(InterceptorRegistry registry) {
//静态资源； *.css,*.js
//SpringBoot已经做好了静态资源映射
registry.addInterceptor(new LoginHandlerInterceptor()).addPathPatterns("/**");
// .excludePathPatterns("/index.html","/","/user/login","/static/**","/webjars/**");
// /** 表示拦截所有路径下的所有请求
// registry.addInterceptor(new LoginHandlerInterceptor())
// .addPathPatterns("/person.html","/Person.html",
// "/questionnaire.html","/Questionnaire.html",
// "/result.html","/Result.html");
}
};
}
}
创建一个拦截器
LoginHandlerInterceptor
package com.controle.lanjie;
import org.springframework.stereotype.Component;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@Component
public class LoginHandlerInterceptor implements HandlerInterceptor {
//目标方法执行之前
@Override
public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
//--------------------------------------------------------添加请求头，允许跨域----方法一
setHeader(name, value)：如果Header中没有定义则添加，如果已定义则用新的value覆盖原用value值。
addHeader(name, value)：如果Header中没有定义则添加，如果已定义则保持原有value不改变。
response.setHeader("Access-Control-Allow-Origin","*");
response.setHeader("Access-Control-Allow-Headers", "*");
//Access-Control-Allow-Methods: 真实请求允许的方法
//Access-Control-Allow-Headers: 服务器允许使用的字段
//Access-Control-Allow-Credentials: 是否允许用户发送、处理 cookie
//Access-Control-Max-Age: 预检请求的有效期，单位为秒。有效期内，不会重复发送预检请求
//获取请求参数
Object user5 = request.getQueryString();
System.out.println(user5);
//获取请求头参数
Object user6 = request.getHeader("currentUser");
System.out.println(user6);
//获取请求方式
Object user7 = request.getMethod();
System.out.println(user7);
//获取请求路径
Object user8 = request.getRequestURI();
System.out.println(user8);
//重定向访问路径
response.sendRedirect("/bbb2");
// 添加请求头
response.addHeader("location","http://baidu.com");
// if (user == null) {
// //未登录,返回登录页面
// System.out.println("第一拦截了，请求前");
//// response.sendRedirect("/LoginError.html");
// return false;
// }else {
// //放行
return true;
// }
}
@Override
public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) {
System.out.println("第二拦截了，请求中");
}
@Override
public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) {
System.out.println("第三拦截了，请求后");
}
}
允许前端跨域方法二 ----添加全局配置类
package com.config;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
@Configuration
public class WebConfig implements WebMvcConfigurer {
/**
* 跨域支持
* @param registry
*/
@Override
public void addCorsMappings(CorsRegistry registry) {
registry.addMapping("/**")
.allowedOrigins("*")
.allowCredentials(true)
.allowedMethods("GET", "POST", "DELETE", "PUT")
.allowedHeaders("*")
.maxAge(3600 * 24);
}
}
还可以通过添加 Filter 的方式，配置 CORS 规则，并手动指定对哪些接口有效。---这个我没试过，上面2种亲测ok
@Bean
public FilterRegistrationBean corsFilter() {
UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
CorsConfiguration config = new CorsConfiguration();
config.setAllowCredentials(true); config.addAllowedOrigin("http://localhost:9000");
config.addAllowedOrigin("null");
config.addAllowedHeader("*");
config.addAllowedMethod("*");
source.registerCorsConfiguration("/**", config); // CORS 配置对所有接口都有效
FilterRegistrationBean bean = newFilterRegistrationBean(new CorsFilter(source));
bean.setOrder(0);
return bean;
}
三更草堂是向下面那样写的 亲测成功
bilibili.com/video/BV1U44y1W77D
package com.qingge.springboot.config;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.cors.CorsConfiguration;
import org.springframework.web.cors.UrlBasedCorsConfigurationSource;
import org.springframework.web.filter.CorsFilter;
@Configuration
public class CorsConfig {
// 当前跨域请求最大有效时长。这里默认1天
private static final long MAX_AGE = 24 * 60 * 60;
@Bean
public CorsFilter corsFilter() {
UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
CorsConfiguration corsConfiguration = new CorsConfiguration();
corsConfiguration.addAllowedOrigin("*"); // 1 设置访问源地址
corsConfiguration.addAllowedHeader("*"); // 2 设置访问源请求头
corsConfiguration.addAllowedMethod("*"); // 3 设置访问源请求方法
corsConfiguration.setMaxAge(MAX_AGE);
source.registerCorsConfiguration("/**", corsConfiguration); // 4 对接口配置跨域设置
return new CorsFilter(source);
}
}增加跨域配置解决的方法见 https://www.cnblogs.com/kaibindirver/p/16189077.html
