英文:
How to get a String inside an Object Array using MongoDB Java?
问题
我试图学习 MongoDB 并且我想要获取对象数组中的字符串，我的 MongoDB 文档如下所示：
{
"_id" : ObjectId("5f1507fed91e81246c409a59"),
"identification" : "punishment",
"lastID" : 2,
"punishmentsTypes" : [
{
"category" : "OFENSA_JOGADOR",
"reason" : "Ofensa a Jogador",
"group" : [
"HELPER",
"MODERATOR",
"ADMINISTRATOR",
"MANAGER",
"MASTER"
],
"description" : "Ofender algum jogador",
"cases" : [
{
"1" : {
"type" : "MUTE",
"duration" : 604800000
}
},
{
"2" : {
"type" : "BAN",
"duration" : 0
}
}
]
},
{
"category" : "FALSIFICACAO",
"reason" : "Falsificação de provas",
"group" : [
"ADMINISTRATOR",
"MANAGER",
"MASTER"
],
"description" : "Falsicar provas ao denunciar um jogador em nosso fórum",
"cases" : [
{
"1" : {
"type" : "BAN",
"duration" : 0
}
}
]
},
{
"category" : "HACK",
"reason" : "Hack",
"group" : [
"MODERATOR",
"ADMINISTRATOR",
"MANAGER",
"MASTER"
],
"description" : "Uso de cheats ou programas ilícitos",
"cases" : [
{
"1" : {
"type" : "BAN",
"duration" : 7776000000.0
}
},
{
"2" : {
"type" : "BAN",
"duration" : 0
}
}
]
}
],
"unpunishmentTypes" : [
{}
]
}
我尝试了以下代码：
MongoCollection<Document> collection = mongoDatabase.getCollection("settings");
BasicDBObject query = new BasicDBObject();
BasicDBObject field = new BasicDBObject();
query.put("id", "punish");
field.put("punishmentsTypes", 1);
field.put("_id", 0);
Document test = collection.find(query).projection(field).first();
assert test != null;
Object object = test.get("punishmentsTypes");
System.out.println(object);
这是输出结果：
[Document{{category=OFENSA_JOGADOR}},
Document{{category=FALSIFICACAO}}, Document{{category=HACK}}]
如何仅获取类别字符串，以便输出为：OFENSA_JOGADOR, FALSIFICACAO, HACK?
英文:
I'm trying to learn MongoDB and I want to get a String inside an Object Array, my MongoDB document is here:
{
"_id" : ObjectId("5f1507fed91e81246c409a59"),
"identification" : "punishment",
"lastID" : 2,
"punishmentsTypes" : [
{
"category" : "OFENSA_JOGADOR",
"reason" : "Ofensa a Jogador",
"group" : [
"HELPER",
"MODERATOR",
"ADMINISTRATOR",
"MANAGER",
"MASTER"
],
"description" : "Ofender algum jogador",
"cases" : [
{
"1" : {
"type" : "MUTE",
"duration" : 604800000
}
},
{
"2" : {
"type" : "BAN",
"duration" : 0
}
}
]
},
{
"category" : "FALSIFICACAO",
"reason" : "Falsificação de provas",
"group" : [
"ADMINISTRATOR",
"MANAGER",
"MASTER"
],
"description" : "Falsicar provas ao denunciar um jogador em nosso fórum",
"cases" : [
{
"1" : {
"type" : "BAN",
"duration" : 0
}
}
]
},
{
"category" : "HACK",
"reason" : "Hack",
"group" : [
"MODERATOR",
"ADMINISTRATOR",
"MANAGER",
"MASTER"
],
"description" : "Uso de cheats ou programas ilícitos",
"cases" : [
{
"1" : {
"type" : "BAN",
"duration" : 7776000000.0
}
},
{
"2" : {
"type" : "BAN",
"duration" : 0
}
}
]
}
],
"unpunishmentTypes" : [
{}
]
}
I've tried this:
MongoCollection<Document> collection = mongoDatabase.getCollection("settings");
BasicDBObject query = new BasicDBObject();
BasicDBObject field = new BasicDBObject();
query.put("id", "punish");
field.put("punishmentsTypes", 1);
field.put("_id", 0);
Document test = collection.find(query).projection(field).first();
assert test != null;
Object object = test.get("punishmentsTypes");
System.out.println(object);
And that's the output:
> [Document{{category=OFENSA_JOGADOR}},
> Document{{category=FALSIFICACAO}}, Document{{category=HACK}}]
How can I get only the category string, to the output be: OFENSA_JOGADOR, FALSIFICACAO, HACK?
答案1
得分: 1
我不确定你是如何通过你的查询得到那个结果的，但这是我获取结果的方法：
MongoCollection<Document> collection = mongoDatabase.getCollection("settings");
Document query = new Document();
query.put("identification", "punishment");
Document test = collection.find(query).first();
List<Document> punishmentsTypes = test.getList("punishmentsTypes", Document.class);
for (Document document : punishmentsTypes) {
String category = document.getString("category");
System.out.println(category);
}
英文:
I'm not sure how did you get that result with your query but here is how I get your result:
MongoCollection<Document> collection = mongoDatabase.getCollection("settings");
Document query = new Document();
query.put("identification", "punishment");
Document test = collection.find(query).first();
List<Document> punishmentsTypes = test.getList("punishmentsTypes", Document.class);
for (Document document : punishmentsTypes) {
String category = document.getString("category");
System.out.println(category);
}
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