1、新增maven依賴註解

       <!--跨域需要的jar包-->
        <dependency>
            <groupId>com.thetransactioncompany</groupId>
            <artifactId>java-property-utils</artifactId>
            <version>1.9.1</version>
        </dependency>
        <dependency
 
>
            <groupId>com.thetransactioncompany</groupId>
            <artifactId>cors-filter</artifactId>
            <version>2.5</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId
 
>javax.servlet-api</artifactId>
            <version>3.1.0</version>
            <scope>provided</scope>
        </dependency>

2、新增跨域請求配置類CorsConfig

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 {
    private CorsConfiguration buildConfig() {
        CorsConfiguration corsConfiguration = new CorsConfiguration();
        corsConfiguration.addAllowedOrigin("*"); // 1
        corsConfiguration.addAllowedHeader("*"); // 2
        corsConfiguration.addAllowedMethod("*"); // 3
        return corsConfiguration;
    }

    @Bean
    public CorsFilter corsFilter() {
        UrlBasedCorsConfigurationSource source = new UrlBasedCorsConfigurationSource();
        source.registerCorsConfiguration("/**", buildConfig()); // 4
        return new CorsFilter(source);
    }
}

3、在接收到OPTIONS請求時候，需要返回狀態碼為202，並且設定響應頭部（根據需求變更）

HttpServletResponse httpResponse = response;
        httpResponse.setCharacterEncoding("UTF-8");
        httpResponse.setContentType("application/json; charset=utf-8");
        httpResponse.setHeader("Access-Control-Allow-Origin","*");
        httpResponse.setHeader("Access-Control-Allow-Credentials", "true");
        httpResponse.setHeader("Access-Control-Allow-Methods", "POST,GET,OPTIONS,DELETE,PATCH,PUT");
        httpResponse.setHeader("Access-Control-Max-Age", "3600");
        httpResponse.setHeader("Access-Control-Allow-Headers", "Origin,X-Requested-With,x-requested-with,X-Custom-Header," +
                "Content-Type,Accept,Authorization");
        String method = request.getMethod();
        if ("OPTIONS".equalsIgnoreCase(method)){
            logger.info("OPTIONS請求");
            httpResponse.setStatus(HttpServletResponse.SC_ACCEPTED);
        }