如何通过后台代码获取map类型如下所示的数据：

如何通过后台代码获取map类型如下所示的数据：

data = {

                "ubuntu":{"pkg_type":"deb","boot_type":"upstart"},
                "centOS":{"pkg_type":"rpm","boot_type":"systemd"}

            };

后台json返回一个Map类型的数据：

public Map<String,Object>  selectLdjqpz(){

        Map<String,Object> result = new LinkedHashMap<String,Object>();

              Map<String,String> map2 = new HashMap<String,String>();

                     map2.put("pkg_type","rpm");

                     map2.put("boot_type","systemd");

                     result.put("centOS",map2);

              Map<String,String> map1 = new HashMap<String,String>();

                    map1.put("pkg_type","deb");

                    map1.put("boot_type","upstart");

                    result.put("ubuntu",map1);

        return result;

}

在后台打印的是一个：{centOS={boot_type=systemd, pkg_type=rpm}, ubuntu={boot_type=upstart, pkg_type=deb}}