React+ SpringBoot 跨域问题

1.新建CORSConfiguration.java 文件
2.编写代码

package com.vuvivian.jianshu;

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.CorsRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

@Configuration
public class CORSConfiguration extends WebMvcConfigurerAdapter {
    @Override
    public void addCorsMappings(CorsRegistry registry){
        registry
                .addMapping("/**")
                .allowedMethods("*")
                .allowedOrigins("*")
                .allowedHeaders("*");
    }
}

3.写个接口，新建类：HelloController ，编写代码

package com.vuvivian.jianshu;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloController {
    @RequestMapping(value = "/hello",method = RequestMethod.GET)
    public String say() {
        return  "区块链";
    }
}

4.React调用axios方法，调接口

  axios.get('http://localhost:8080/hello').then((res)=>{
            const data = res.data;
            console.log(data)
        }).catch(()=>{
            console.log("error")
        })

5.打开页面，查看结果