在前后端分离的情况下，后台所写的接口在前端调用的时候，可能前端浏览器已经读取到了数据，但是在前端代码ajax请求的时候，请求回调里会出现页面跨域的控制台打印错误，这个时候只需要后台配置一下头部请求就可以解决
我用的是SpringBoot，讲解一下如何配置SpringBoot来解决页面跨域问题
将关于web的配置信息都用注解的形式来配置，相对比较方便
import com.alibaba.fastjson.serializer.SerializerFeature;
import com.alibaba.fastjson.support.config.FastJsonConfig;
import com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter;
import com.uhope.web.codegenerator.filter.ServiceFilter;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.boot.autoconfigure.http.HttpMessageConverters;
import org.springframework.boot.web.servlet.FilterRegistrationBean;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.converter.HttpMessageConverter;
import org.springframework.web.servlet.config.annotation.ResourceHandlerRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import java.nio.charset.Charset;
/**
* Spring MVC 配置
* @author Chenbin
*/
@Configuration
public class WebMvcConfig extends WebMvcConfigurerAdapter {
private final Logger logger = LoggerFactory.getLogger(WebMvcConfig.class);
/**
* 解决路径资源映射问题
*
* @param registry
*/
@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/");
registry.addResourceHandler("/static/**").addResourceLocations("classpath:/static/");
}
/**
* 使用fastJson代替Jackjson解析JSON数据
*
* @return
*/
@Bean
public HttpMessageConverters fastJsonHttpMessageConverters() {
FastJsonHttpMessageConverter fastConverter = new FastJsonHttpMessageConverter();
FastJsonConfig fastJsonConfig = new FastJsonConfig();
/*
* 转换为JSON字符串，默认:
* WriteNullListAsEmpty List字段如果为null,输出为[],而非null
* WriteNullStringAsEmpty 字符类型字段如果为null,输出为”“,而非null
* WriteMapNullValue 是否输出值为null的字段,默认为false
*/
fastJsonConfig.setSerializerFeatures(SerializerFeature.WriteNullListAsEmpty, SerializerFeature.WriteNullStringAsEmpty, SerializerFeature.WriteMapNullValue, SerializerFeature.WriteDateUseDateFormat);
fastConverter.setFastJsonConfig(fastJsonConfig);
fastConverter.setDefaultCharset(Charset.forName("UTF-8"));
HttpMessageConverter<?> converter = fastConverter;
return new HttpMessageConverters(converter);
}
/**
* 这个Filter 解决页面跨域访问问题
*/
@Bean
public FilterRegistrationBean omsFilter() {
FilterRegistrationBean registration = new FilterRegistrationBean();
registration.setFilter(new ServiceFilter());
registration.addUrlPatterns("/*");
registration.setName("MainFilter");
registration.setAsyncSupported(true);
registration.setOrder(1);
return registration;
}
}
其中JSON数据返回需要引入阿里巴巴FastJson这个依赖，可以自行去pom.xml文件中引入
这样还不够，还需要
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.servlet.*;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
/**
* @author Chenbin
*/
public class ServiceFilter implements Filter {
private static final Logger LOGGER = LoggerFactory.getLogger(ServiceFilter.class);
@Override
public void doFilter(ServletRequest request, ServletResponse response, FilterChain filterChain)
throws IOException, ServletException {
HttpServletResponse resp = (HttpServletResponse) response;
HttpServletRequest req = (HttpServletRequest) request;
// 解决页面跨域访问问题
resp.setHeader("Access-Control-Allow-Origin", "*");
resp.setHeader("Access-Control-Allow-Credentials", "true");
resp.setHeader("Access-Control-Allow-Methods", "*");
resp.setHeader("Access-Control-Allow-Headers", "Content-Type,Access-Token");
resp.setHeader("Access-Control-Expose-Headers", "*");
filterChain.doFilter(req, resp);
}
@Override
public void init(FilterConfig filterConfig) throws ServletException {
}
@Override
public void destroy() {
}
}
这两个类配置好了以后，重启服务，再与前端交互就不会出现这样的跨域问题了，因为在Filter这个类里加了一个请求头Access-Control-Allow-Origin
//跨域认证 axios.defaults.withCredentials = false axios.defaults.crossDomain = true
2个类复制进去
启动类添加包扫描
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
/**
* Cros协议的配置类。
* 继承WebMvcConfigurerAdapter，并且重写方法addCorsMappings。
* addCorsMappings方法是用于增加Cros协议配置的方法。默认的实现是空实现。也就是说，在默认的配置环境中，是不进行Cros协议的配置的。
*/
@Configuration
public class CrosConfiguration extends WebMvcConfigurerAdapter {
@Autowired
ProcessInterceptor processInterceptor;
@Override
public void addInterceptors(InterceptorRegistry registry) {
// 添加拦截器(拦截器中只有preHandle返回true时才继续执行下一个拦截器或者controller，否则直接返回)
// registry.addInterceptor(logInterceptor).addPathPatterns("/**");
registry.addInterceptor(processInterceptor).addPathPatterns("/**");
//registry.addInterceptor(csrCheckInterceptor).addPathPatterns("/**");
//registry.addInterceptor(menuAuthInterceptor).addPathPatterns("/**");
super.addInterceptors(registry);
}
/**
* 就是注册的过程，注册Cors协议的内容。
* 如： Cors协议支持哪些请求URL，支持哪些请求类型，请求时处理的超时时长是什么等。
* @param registry - 就是用于注册Cros协议内容的一个注册器。
*/
@Override
public void addCorsMappings(CorsRegistry registry) {
registry
.addMapping("/**")// 所有的当前站点的请求地址，都支持跨域访问。
.allowedMethods("GET", "POST", "PUT", "DELETE","OPTIONS") // 当前站点支持的跨域请求类型是什么。
.allowCredentials(true) // 是否支持跨域用户凭证
.allowedHeaders("*")
.allowedOrigins("*") // 所有的外部域都可跨域访问。 如果是localhost则很难配置，因为在跨域请求的时候，外部域的解析可能是localhost、127.0.0.1、主机名
.maxAge(3600); // 超时时长设置为1小时。 时间单位是秒。
}
}
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;
/**
* @author:Administrator
* @date:2019/10/9
*/
@Component
public class ProcessInterceptor implements HandlerInterceptor {
@Override
public boolean preHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o) throws Exception {
httpServletResponse.setHeader("Access-Control-Allow-Headers", "X-Requested-With, Accept, Content-Type,Authorization");
httpServletResponse.setHeader("Access-Control-Allow-Methods", "PUT,POST,GET,DELETE,OPTIONS");
String origin = httpServletRequest.getHeader("Origin");
httpServletResponse.setHeader("Access-Control-Allow-Origin", "*");
// 是否允许浏览器携带用户身份信息（cookie）,设置为true,必须设置域名,不能使用通配符
// httpServletResponse.setHeader("Access-Control-Allow-Credentials", "true");
// httpServletResponse.setHeader("Access-Control-Allow-Origin", "*");
// httpServletResponse.setHeader("Access-Control-Allow-Headers", "Content-Type,Content-Length, Authorization, Accept,X-Requested-With");
// httpServletResponse.setHeader("Access-Control-Allow-Methods", "PUT,POST,GET,DELETE,OPTIONS");
String method = httpServletRequest.getMethod();
if (method.equals("OPTIONS")) {
httpServletResponse.setStatus(200);
return false;
}
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 {
}
}
以上为个人经验，希望能给大家一个参考，也希望大家多多支持。
