list集合转换成json类型

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";
    }

打印结果：

[{"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]

下载是maven引入json的包：

        <!-- 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>