Gson替换掉多漏洞的FastJson

<!-- gson -->
    <dependency>
      <groupId>com.google.code.gson</groupId>
      <artifactId>gson</artifactId>
      <version>2.8.5</version>
    </dependency>

DemoVo vo = new DemoVo();
System.out.println(new Gson().toJson(vo));