急求java任务解决方案。。。做了好几天，头疼啊。本人小白。

Question

{
"tables": [
{
"name_en": "atable",
"name_ch": "表中文名",
"column": [
{
"name_en": "columnA1",
"name_ch": "中文名",
"colType": "列类型",
"keyType": "PK/FK"
},
{
"name_en": "columnA2",
"name_ch": "中文名",
"colType": "列类型",
"keyType": "PK/FK"
}
],
"select_columns": [
{
"name_en": "sa1",
"name_ch": "中文名",
"colType": "列类型",
"keyType": "PK/FK"
},
{
"name_en": "sa2",
"name_ch": "中文名",
"colType": "列类型",
"keyType": "PK/FK"
}
],
"order_columns": [
{
"name_en": "oa1",
"name_ch": "中文名",
"colType": "列类型",
"keyType": "PK/FK"
},
{
"name_en": "oa2",
"name_ch": "中文名",
"colType": "列类型",
"keyType": "PK/FK"
}
],
"where_columns": [
{
"name_en": "wa1",
"name_ch": "中文名",
"colType": "列类型",
"keyType": "PK/FK"
},
{
"name_en": "wa2",
"name_ch": "中文名",
"colType": "列类型",
"keyType": "PK/FK"
}
]
},
{
"name_en": "btable",
"name_ch": "表中文名",
"column": [
{
"name_en": "columnB1",
"name_ch": "中文名",
"colType": "列类型",
"keyType": "PK/FK"
},
{
"name_en": "columnB2",
"name_ch": "中文名",
"colType": "列类型",
"keyType": "PK/FK"
}
],
"select_columns": [
{
"name_en": "sb1",
"name_ch": "中文名",
"colType": "列类型",
"keyType": "PK/FK"
},
{
"name_en": "sb2",
"name_ch": "中文名",
"colType": "列类型",
"keyType": "PK/FK"
}
],
"order_columns": [
{
"name_en": "ob1",
"name_ch": "中文名",
"colType": "列类型",
"keyType": "PK/FK"
},
{
"name_en": "ob2",
"name_ch": "中文名",
"colType": "列类型",
"keyType": "PK/FK"
}
],
"where_columns": [
{
"name_en": "wb1",
"name_ch": "中文名",
"colType": "列类型",
"keyType": "PK/FK"
},
{
"name_en": "wb2",
"name_ch": "中文名",
"colType": "列类型",
"keyType": "PK/FK"
}
]
},
{
"name_en": "ctable",
"name_ch": "表中文名",
"column": [
{
"name_en": "columnC1",
"name_ch": "中文名",
"colType": "列类型",
"keyType": "PK/FK"
},
{
"name_en": "columnC2",
"name_ch": "中文名",
"colType": "列类型",
"keyType": "PK/FK"
}
],
"select_columns": [
{
"name_en": "sc1",
"name_ch": "中文名",
"colType": "列类型",
"keyType": "PK/FK"
},
{
"name_en": "sc2",
"name_ch": "中文名",
"colType": "列类型",
"keyType": "PK/FK"
}
],
"order_columns": [
{
"name_en": "oc1",
"name_ch": "中文名",
"colType": "列类型",
"keyType": "PK/FK"
},
{
"name_en": "oc2",
"name_ch": "中文名",
"colType": "列类型",
"keyType": "PK/FK"
}
],
"where_columns": [
{
"name_en": "wc1",
"name_ch": "中文名",
"colType": "列类型",
"keyType": "PK/FK"
},
{
"name_en": "wc2",
"name_ch": "中文名",
"colType": "列类型",
"keyType": "PK/FK"
}
]
}
],
"relations": [
{
"tableA": "atable",
"columnA": "columnA1",
"tableB": "btable",
"columnB": "columnB1",
"type": "leftjoin"
},
{
"tableA": "btable",
"columnA": "columnB2",
"tableB": "ctable",
"columnB": "columnC2",
"type": "innerjoin"
}
]
}

这是一串已知的JSON，有tables和relations两个对象。table里面有三张表，每张表里的coulum指该表包含的所有字段，select__columns指要查询的所有字段，ord er_column指要排序的所有字段，where_column指条件所有字段。relations里面是连接查询。

要求：输入一串json，返回一句连接查询的SQL语句。（json里面表数据会根据输入而不同）。

我做了很多方案：
1、创建实体类的话，就不能解决输入不确定参数数量的问题，比如我不知道几张表，每张表要select多少字段；
2、如果一股脑将所输入的json全部存入一个或者多个list集合里面，那我就不能解决最后拼接成一句sql语句的问题；

关键点就是，固定表数量或者select数量，我可以很好的解决，但是，不确定数量的话，我就很难输出并拼接成一句sql语句。

求大神。。。刚实习，头疼，四天了。。没做出来。

Answer 1

类似输出这种sql语句。