public String gettext(HttpServletRequest request,HttpServletResponse response){

        List<xuanhuan_> xuanhuan = service.getxuanhuan();

        JSONArray json = JSONArray.fromObject(xuanhuan);

        System.out.println(json);//在这里可以看到，json类型可以直接打印出来

        return "/index";

    }

[{"content":"","id":0,"name":"《测试》1","shijian":null},{"content":"","id":0,"name":"《测试》2","shijian":null},{"content":"","id":0,"name":"《测试》3","shijian":null},{"content":"","id":0,"name":"《测试》4","shijian":null},{"content":"","id":0,"name":"《测试》5","shijian":null},null,null,null]

        <!-- json的包，不是项目自带的 -->

        <dependency>

            <groupId>net.sf.json-lib</groupId>

            <artifactId>json-lib</artifactId>

            <version>2.4</version>

            <classifier>jdk15</classifier>

        </dependency>