Java通過mongo-java-driver-3.0+查詢mongodb資料庫
阿新 • • 發佈：2018-12-24
本文以mongo-java-driver-3.5.0.jar為例
1 基本查詢關鍵字（對應的sql語句）：
| MongoDB Aggregation Operators | SQL Terms, Functions, and Concepts |
|---|---|
| $match | WHERE/HAVING |
| $group | GROUP BY |
| $project | SELECT |
| $limit | LIMIT |
| $sort (降序:-1 升序:1) | ORDER BY (降序:DESC 升序:ASC預設) |
| $skip 跳過n個 | 持久化框架有介面 |
| $sum | SUM()/COUNT() |
| $in | IN() |
| $nin | NOT IN() |
| $or | OR |
| $and | AND |
| $regex 模糊查詢 | LIKE |
| $gt | > |
| $gte | >= |
| $lt | < |
| $lte | <= |
| $ne | != |
| = |
2 構造複雜查詢條件的3種方法：
2.1 測試資料
{ "_id" : { "$oid" : "59c8cbea6157d6c78dab4ff0" }, "name" : "yy", "password" : "123" 2.3 實現構造複雜查詢條件的3種方法：
public static MongoCollection<Document> connect() {
@SuppressWarnings("resource")
MongoClient client = new MongoClient("127.0.0.1", 27017);
MongoDatabase db = client.getDatabase("test");
MongoCollection<Document> collection = db.getCollection("user");
return collection;
}
public static List<Document> findBy(Bson filter) {
List<Document> results = new ArrayList<Document>();
FindIterable<Document> iterables = connect().find(filter);
MongoCursor<Document> cursor = iterables.iterator();
while (cursor.hasNext()) {
results.add(cursor.next());
}
return results;
}
public static List<Document> findBy1(DBObject filter) {
List<Document> results = new ArrayList<Document>();
FindIterable<Document> iterables = connect().find((Bson) filter);
MongoCursor<Document> cursor = iterables.iterator();
while (cursor.hasNext()) {
results.add(cursor.next());
}
return results;
}
// 方法1：運用Filters.and新增複合條件；
@Test
public void testFindByLickQuery2(){
int iid = 2;
String name = "yy";
String nickname = "ygirl2";
Bson filter = null;
if (iid >= 0) {
if (name != "") {
if (nickname != "") {
filter = Filters.and(Filters.gte("iid", iid), Filters.eq("nickname", nickname), Filters.regex("name", name));
} else {
filter = Filters.and(Filters.gte("iid", iid), Filters.regex("name", name));
}
} else {
if (nickname != "") {
filter = Filters.and(Filters.gte("iid", iid), Filters.eq("nickname", nickname));
} else {
filter = Filters.and(Filters.gte("iid", iid));
}
}
} else {
if (name != "") {
if (nickname != "") {
filter = Filters.and(Filters.eq("nickname", nickname), Filters.regex("name", name));
} else {
filter = Filters.and(Filters.regex("name", name));
}
} else {
if (nickname != "") {
filter = Filters.and(Filters.eq("nickname", nickname));
} else {
filter = Filters.and();
}
}
}
List<Document> results = findBy(filter);
for(Document doc : results){
System.out.println(doc.toJson());
}
// { "_id" : { "$oid" : "59c8cbea6157d6c78dab4ff0" }, "name" : "yy", "password" : "123", "nickname" : "ygirl2", "iid" : 2 }
// { "_id" : { "$oid" : "59c9ec75a4e55c541a000003" }, "name" : "yy", "password" : "123", "nickname" : "ygirl2", "iid" : 8.0, "isRead" : false, "createTime" : { "$date" : 1506405705952 }, "money" : 88.88 }
}
// 方法2：運用Document filter.append新增複合條件；
@Test
public void testFindByLickQuery1(){
int iid = 3, iid2 = 4;
String name = "";
String nickname = "";
Document filter = new Document();
if (iid >= 0) {
filter.append("iid", new Document("$gte", iid));
}
// 得到iid<=4結果；
// iid>=3條件被覆蓋，Document.append不適合在同一個結果新增多個條件
if (iid2 >= 0) {
filter.append("iid", new Document("$lte", iid2));
}
if (name != "") {
filter.append("name",new Document("$regex", name));
}
if (nickname != "") {
filter.append("nickname",nickname);
}
List<Document> results = findBy(filter);
for(Document doc : results){
System.out.println(doc.toJson());
}
// { "_id" : { "$oid" : "59c8cbea6157d6c78dab4ff0" }, "name" : "yy", "password" : "123", "nickname" : "ygirl2", "iid" : 2 }
// { "_id" : { "$oid" : "59b34277beca1aaeaf1d1fbe" }, "name" : "yan", "password" : "ygirlyan", "nickname" : "ygirl2", "iid" : 3.0 }
// { "_id" : { "$oid" : "59b34282beca1aaeaf1d1fbf" }, "name" : "yan", "password" : "ygirlyan", "nickname" : "ygirl2", "iid" : 4.0 }
}
// 方法3：運用DBObject.put新增複合條件；
@Test
public void testFindByLickQuery1Copy(){
int iid = 3, iid2 = 4;
String name = "";
String nickname = "";
DBObject filter = new BasicDBObject();
if (iid >= 0) {
filter.put("iid", new BasicDBObject("$gte", iid));
}
// 得到iid<=4結果；
// iid>=3條件被覆蓋，Document.append不適合在同一個結果新增多個條件
if (iid2 >= 0) {
if (iid >= 0) {
BasicDBObject[] queryObjectAnd = new BasicDBObject[] { new BasicDBObject("iid", new BasicDBObject("$gte", iid)),
new BasicDBObject("iid", new BasicDBObject("$lte", iid2)) };
filter.put("$and", queryObjectAnd);
} else {
filter.put("iid", new BasicDBObject("$lte", iid2));
}
}
if (name != "") {
filter.put("name",new BasicDBObject("$regex", name));
}
if (nickname != "") {
filter.put("nickname",nickname);
}
List<Document> results = findBy1(filter);
for(Document doc : results){
System.out.println(doc.toJson());
}
// { "_id" : { "$oid" : "59b34277beca1aaeaf1d1fbe" }, "name" : "yan", "password" : "ygirlyan", "nickname" : "ygirl2", "iid" : 3.0 }
// { "_id" : { "$oid" : "59b34282beca1aaeaf1d1fbf" }, "name" : "yan", "password" : "ygirlyan", "nickname" : "ygirl2", "iid" : 4.0 }
} 2.3 分析構造複雜查詢條件的3種方法異同：
| 方法 | 實現 | 難易程度 | 能否給同一個欄位加大於1個約束條件 | 適用於 |
|---|---|---|---|---|
| 方法1 | Bson filter=Filters.and(Filters 1,…) | 條件越多實現越困難，if-else越複雜 | 能 | 查詢條件少且固定永遠不變 |
| 方法2 | Document f=append(key, v) Document f=append(key, newBasicDBObject(“$gte”,v)) |
條件越多實現不會太困難 | 不能，後面的append條件會覆蓋前面的 | 查詢條件多且每個屬性查詢條件<=1 |
| 方法3 | DBObject filter=put(“iid”,new BasicDBObject(“$gte”,v)); | 條件越多實現不會太困難 | 能 | 適用於一切查詢，特別適用於複雜條件查詢應用 |
3 其他查詢關鍵字應用：
3.1 String型別按條件聚合
@Test
public void testGroup() {
/* Group操作*/
//DBObject groupFields = new BasicDBObject("_id", new BasicDBObject("name", "$name").append("nickname", "$nickname"));
// 1 加入標誌項_id，即聚合欄位值;
DBObject groupFields = new BasicDBObject("_id", "$name");
// 2 加入統計數count，即聚合個數；
groupFields.put("count", new BasicDBObject("$sum", 1));
DBObject group = new BasicDBObject("$group", groupFields);
// 排序操作 ，按count降序
DBObject sortchBasicDBObjet = new BasicDBObject("$sort", new BasicDBObject("count",-1));
// 分頁操作.skip(startRow)，首先取2個記錄，再跳過1個記錄取出第二個記錄顯示出來；
DBObject limitBasicDBObjet = new BasicDBObject("$limit",2);
DBObject limitBasicDBObjet2 = new BasicDBObject("$skip",2);
// project 操作 : 過濾查詢顯示欄位個數,db.books.aggregate( [ { $project : { _id: 0, name : 1 , password : 1 }]);只顯示name和password
// DBObject projectBasicDBObjet = new BasicDBObject("$project", new BasicDBObject("_id",0).append("times", "$_id.times").append("user_id", "$_id.user_id").append("user_account", "$_id.user_account").append("count", 1));
List<Bson> list = new ArrayList<Bson>();
list.add((Bson) group);
list.add((Bson) sortchBasicDBObjet);
// $limit和$skip add到list順序不一樣，結果不一樣
list.add((Bson) limitBasicDBObjet2);
list.add((Bson) limitBasicDBObjet);
// list.add((Bson) limitBasicDBObjet2);
List<Document> results = MongoDb.group(list);;
for(Document doc : results){
System.out.println(doc.toJson());
}
}
/*
*
* isRead "0"表示未讀，"1"表示已讀
*/
public List<Object> findIfreadAlarmLog(String isRead, String CommunityName, String EQAddress) {
MongoCollection<Document> collection = getMongodbCollection();
// 新增統計統計
//DBObject matchBasicDBObjet = new BasicDBObject("$match",new BasicDBObject("IsRead", "0"));
DBObject queryCondition = new BasicDBObject();
queryCondition.put("IsRead", isRead);
if (CommunityName != null && !"".equals(CommunityName)) {
// 模糊匹配
queryCondition.put("CommunityName", new BasicDBObject("$regex", CommunityName));
}
if (EQAddress != null && !"".equals(EQAddress)) {
// 模糊匹配
queryCondition.put("EQAddress", new BasicDBObject("$regex", EQAddress));
}
DBObject matchBasicDBObjet = new BasicDBObject("$match", queryCondition);
// 新增統計條件
DBObject groupFields = new BasicDBObject("_id", new BasicDBObject("CommunityID", "$CommunityID").append("CommunityName", "$CommunityName").append("EQName", "$EQName")
.append("EQAccount", "$EQAccount").append("EQAddress", "$EQAddress").append("Coordinate", "$Coordinate").append("SingleCoordinate", "$SingleCoordinate"));
// 加入統計數count，即聚合個數；
groupFields.put("count", new BasicDBObject("$sum", 1));
DBObject group = new BasicDBObject("$group", groupFields);
// 新增顯示條件
DBObject projectBasicDBObjet = new BasicDBObject("$project", new BasicDBObject("_id",0).append("CommunityID", "$_id.CommunityID").append("CommunityName", "$_id.CommunityName").append("EQName", "$_id.EQName")
.append("EQAccount", "$_id.EQAccount").append("EQAddress", "$_id.EQAddress").append("Coordinate", "$_id.Coordinate").append("SingleCoordinate", "$_id.SingleCoordinate").append("count", 1));
List<Bson> list = new ArrayList<Bson>();
list.add((Bson) matchBasicDBObjet);
list.add((Bson) group);
list.add((Bson) projectBasicDBObjet);
AggregateIterable<Document> iterables = collection.aggregate(list);
List<Object> results = new ArrayList<Object>();
MongoCursor<Document> cursor = iterables.iterator();
while (cursor.hasNext()) {
results.add(cursor.next());
}
return results;
}3.2 json格式的查詢
/*
* 先轉換為Object再查詢
*/
public List<String> getHouseHouseAccounts(List<Object> singleCoords , String isRead) {
MongoCollection<Document> collection = getMongodbCollection();
DBObject queryCondition = new BasicDBObject();
List<String> resultArray = new ArrayList<String>();
// 報錯：org.bson.codecs.configuration.CodecConfigurationException: Can't find a codec for class cn.com.vo.Point.,Point包含lng，lat屬性
// queryCondition.put("SingleCoordinate", JsonUtils.jsonToPojo(singleCoord, Point.class));
// 返回空
//queryCondition.put("SingleCoordinate", singleCoord);
// 成功返回，(DBObject) JSON.parse(singleCoord)=JSON.parse(singleCoord)={ "lng" : 102.731653 , "lat" : 25.052474}，88:H20170926000002 88:H20170926000003,H20170926000004
//queryCondition.put("SingleCoordinate", JSON.parse(singleCoord));
// 成功返回，JsonUtils.jsonToPojo(singleCoord, Object.class)={lng=102.731653, lat=25.052474}，88:H20170926000002 88:H20170926000003,H20170926000004
for (Object object : singleCoords) {
//queryCondition.put("SingleCoordinate", JsonUtils.jsonToPojo(singleCoord, Object.class));
queryCondition.put("SingleCoordinate", object);
queryCondition.put("IsRead", isRead);
List<Object> list = new ArrayList<Object>();
FindIterable<Document> findIterable =collection.find((Bson) queryCondition);
MongoCursor<Document> mongoCursor = findIterable.iterator();
while(mongoCursor.hasNext()){
Document document=mongoCursor.next();
list.add(document);
}
List<AlarmLog> alarmLogLists = JsonUtils.jsonToList(JsonUtils.objectToJson(list), AlarmLog.class);
for (AlarmLog alarmLog : alarmLogLists) {
resultArray.add("'" + alarmLog.getHouseAccount() + "'");
}
}
//return StringUtils.collectionToDelimitedString(resultArray, ",");
return resultArray;
}3.3 $or和$and關鍵字查詢
/**
* Document OR AND 查詢:db.user.find({"likes": {$gt:50}, $or: [{"by": "菜鳥教程"},{"title": "MongoDB 教程"}]}).pretty()；
* 適合少條件且條件不變的查詢，適合單欄位多條件查詢
*/
@Test
public void testFindByOrAnd(){
// (查詢iid等於2或者iid等於8的資料) 失敗 只能查到8
Document filter = new Document();
filter.append("iid", 2);
filter.append("iid", 8);
List<Document> results = MongoDb.findBy(filter);
// $or (查詢iid等於2或者iid等於8的資料)
BasicDBObject queryObjectOr = new BasicDBObject().append(
"$or",
new BasicDBObject[] { new BasicDBObject("iid", 2),
new BasicDBObject("iid", 8) });
// (查詢iid等於2並且name等於nie的資料) 成功查出相應資料
Document filter2 = new Document();
filter2.append("iid", 2);
filter2.append("name", "yy");
List<Document> results2 = MongoDb.findBy(filter2);
// $and(查詢iid等於2並且name等於nie的資料)
BasicDBObject queryObjectAnd = new BasicDBObject().append("$and",
new BasicDBObject[] { new BasicDBObject("iid", 2),
new BasicDBObject("name", "yy") });
List<Document> results3 = MongoDb.findBy(queryObjectOr);
List<Document> results4 = MongoDb.findBy(queryObjectAnd);
for(Document doc : results){
System.out.println(doc.toJson());
}
System.out.println("==========");
for(Document doc : results3){
System.out.println(doc.toJson());
}
System.out.println("==========");
for(Document doc : results4){
System.out.println(doc.toJson());
}
System.out.println("==========");
for(Document doc : results2){
System.out.println(doc.toJson());
}
// { "_id" : { "$oid" : "59c9c1393471f5330c65ccd2" }, "name" : "nie", "password" : "nie", "nickname" : "nn", "iid" : 8 }
// { "_id" : { "$oid" : "59c9ec75a4e55c541a000003" }, "name" : "yy", "password" : "123", "nickname" : "ygirl2", "iid" : 8.0, "isRead" : false, "createTime" : { "$date" : 1506405705952 }, "money" : 88.88 }
// ==========
// { "_id" : { "$oid" : "59c8cbea6157d6c78dab4ff0" }, "name" : "yy", "password" : "123", "nickname" : "ygirl2", "iid" : 2 }
// { "_id" : { "$oid" : "59c9c1393471f5330c65ccd2" }, "name" : "nie", "password" : "nie", "nickname" : "nn", "iid" : 8 }
// { "_id" : { "$oid" : "59c9ec75a4e55c541a000003" }, "name" : "yy", "password" : "123", "nickname" : "ygirl2", "iid" : 8.0, "isRead" : false, "createTime" : { "$date" : 1506405705952 }, "money" : 88.88 }
// ==========
// { "_id" : { "$oid" : "59c8cbea6157d6c78dab4ff0" }, "name" : "yy", "password" : "123", "nickname" : "ygirl2", "iid" : 2 }
// ==========
// { "_id" : { "$oid" : "59c8cbea6157d6c78dab4ff0" }, "name" : "yy", "password" : "123", "nickname" : "ygirl2", "iid" : 2 }
}3.4$in和$nin關鍵字查詢
/**
* Document in nin 查詢
*/
@Test
public void testFindByInNin(){
// $in （查詢iid為1和2的資料）
BasicDBObject queryObjectIn = new BasicDBObject().append("iid", new BasicDBObject(
"$in", new int[] { 2, 8 }));
// $nin （查詢iid不為1,2,3,4,5,6,7,8,9的資料）
BasicDBObject queryObjectNin = new BasicDBObject().append("iid", new BasicDBObject(
"$nin", new int[] { 2, 9 }));
List<Document> results3 = MongoDb.findBy(queryObjectIn);
List<Document> results4 = MongoDb.findBy(queryObjectNin);
for(Document doc : results3){
System.out.println(doc.toJson());
}
// { "_id" : { "$oid" : "59c8cbea6157d6c78dab4ff0" }, "name" : "yy", "password" : "123", "nickname" : "ygirl2", "iid" : 2 }
// { "_id" : { "$oid" : "59c9c1393471f5330c65ccd2" }, "name" : "nie", "password" : "nie", "nickname" : "nn", "iid" : 8 }
// { "_id" : { "$oid" : "59c9ec75a4e55c541a000003" }, "name" : "yy", "password" : "123", "nickname" : "ygirl2", "iid" : 8.0, "isRead" : false, "createTime" : { "$date" : 1506405705952 }, "money" : 88.88 }
}