跨域：指的是浏览器不能执⾏其他⽹站的脚本。它是由浏览器的同源策略造成的，是浏览器对javascript施加的安全限制。
例如：a页⾯想获取b页⾯资源，如果a、b页⾯的协议、域名、端⼝、⼦域名不同，所进⾏的访问⾏动都是跨域的，⽽浏览器
为了安全问题⼀般都限制了跨域访问，也就是不允许跨域请求资源。注意：跨域限制访问，其实是浏览器的限制。理解这⼀点
很重要
同源策略：是指协议，域名，端⼝都要相同，其中有⼀个不同都会产⽣跨域；
直接在Controller方法或者类上增加@CrossOrigin注解，SpringMVC使用@CrossOrigin使用场景要求 jdk1.8+ Spring4.2+
@GetMapping("/hello")
@CrossOrigin
public String hello() {
return "hello:" + simpleDateFormat.format(new Date());
}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 ConfigConfiguration {
@Bean
public CorsFilter CorsFilter() {
CorsConfiguration corsConfiguration = new CorsConfiguration();
corsConfiguration.addAllowedOriginPattern("*");
corsConfiguration.addAllowedHeader("*");
corsConfiguration.addAllowedMethod("*");
corsConfiguration.setAllowCredentials(true);
UrlBasedCorsConfigurationSource ub = new UrlBasedCorsConfigurationSource();
ub.registerCorsConfiguration("/**", corsConfiguration);
return new CorsFilter(ub);
}
}@Component
public class CustomFilter implements Filter {
@Override
public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
HttpServletResponse res = (HttpServletResponse) servletResponse;
// 设置允许Cookie
res.addHeader("Access-Control-Allow-Credentials", "true");
// 允许http://www.xxx.com域（自行设置，这里只做示例）发起跨域请求
res.addHeader("Access-Control-Allow-Origin", "*");
// 设置允许跨域请求的方法
res.addHeader("Access-Control-Allow-Methods", "GET, POST, DELETE, PUT");
// 允许跨域请求包含content-type
res.addHeader("Access-Control-Allow-Headers", "Content-Type,X-CAF-Authorization-Token,sessionToken,X-TOKEN");
if (((HttpServletRequest) servletRequest).getMethod().equals("OPTIONS")) {
servletResponse.getWriter().println("ok");
return;
}
filterChain.doFilter(servletRequest, servletResponse);
}
}import org.springframework.stereotype.Component;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurer;
@Component
public class MyWebMvcConfigurer implements WebMvcConfigurer {
@Override
public void addCorsMappings(CorsRegistry registry) {
registry.addMapping("/**") // 匹配所有的路径
.allowCredentials(true) // 设置允许凭证
.allowedHeaders("*") // 设置请求头
.allowedMethods("GET", "POST", "PUT", "DELETE") // 设置允许的方式
.allowedOriginPatterns("*");
}
}
