创建handle=》MyAccessDeniedHandle类

/**
 * @author etern
 * @title: MyAccessDeniedHandler
 * @projectName springsecuritydemo
 * @description: TODO 设置自定义403响应码
 * @date 2022/1/22 20:24
 */
//因为之后要引用这个类
@Component
public class MyAccessDeniedHandler implements AccessDeniedHandler {
    @Override
    public void handle(HttpServletRequest request, HttpServletResponse response, AccessDeniedException accessDeniedException) throws IOException, ServletException {
        //获取设置响应403状态码
        response.setStatus(HttpServletResponse.SC_FORBIDDEN);
        //设置响应请求头
        response.setHeader("Content-Type", "application/json;charset=utf-8");
        PrintWriter writer = response.getWriter();
        writer.write("{\"status\":\"error\",\"msg\":\"权限不足,请联系管理员\"}");
        //刷新
        writer.flush();
        //关闭
        writer.close();
    }
}

到配置中(SecurityConfig.java)
添加异常处理

//异常处理
http.exceptionHandling()
        //添加异常403自定义处理
        .accessDeniedHandler(myAccessDeniedHandler);