如何在java中像python一样分组json值?

Question

我是java新手，但我对python有一些了解，我需要像这样转换json值:

{'ID':'id1','ref':'ref1','categ':'CATEG_A','pagenb':1},
{'ID':'id2','ref':'ref1','categ':'CATEG_A','pagenb':2,},
{'ID':'id3','ref':'ref1','categ':'CATEG_B','pagenb':3}

:

{'ID':['id1','id2],'ref':'ref1','categ':'CATEG_A'},
{'ID':'id3','ref':'ref1','categ':'CATEG_B',},

在python中，我使用pandas dataframe来分组，但我没有找到在java中这样做的最佳方法类别值是动态可变的，可以更改

Answer 1

https://github.com/octomix/josson

Josson josson = Josson.fromJsonString(
"[" +
"  {"ID":"id1","ref":"ref1","categ":"CATEG_A","pagenb":1}," +
"  {"ID":"id2","ref":"ref1","categ":"CATEG_A","pagenb":2}," +
"  {"ID":"id3","ref":"ref1","categ":"CATEG_B","pagenb":3}" +
"]");

JsonNode node = josson.getNode("group(map(ref, categ), ID).map(ID, key.ref, key.categ)");
System.out.println(node.toPrettyString());

输出

[ {
"ID" : [ "id1", "id2" ],
"ref" : "ref1",
"categ" : "CATEG_A"
}, {
"ID" : [ "id3" ],
"ref" : "ref1",
"categ" : "CATEG_B"
} ]