当前位置：首页 > news >正文

java操作mongodb详解

news 来源：原创 2024/9/21 11:22:35

前言
一切操作都应该以官方文档为准，mongodb官网文档地址： https://www.mongodb.com/docs/ ，网上关于java操作mongodb的文章偏少，而且有些乱。这篇文章是在项目中使用mongodb后的一些总结，希望能帮到大家。

1.创建mongodb客户端（这里注册了自定义解码器，方便直接存java对象）

String linkUrl = "mongodb://" + url;
if (hasAuth) { //需要用户名密码用下面的方式拼接urllinkUrl = "mongodb://" + username + ":" + password + "@" + url + "/" + databaseName;
}
CodecRegistry pojoCodecRegistry = CodecRegistries.fromRegistries(MongoClientSettings.getDefaultCodecRegistry(),CodecRegistries.fromProviders(PojoCodecProvider.builder().automatic(true).build()));MongoClientSettings build = MongoClientSettings.builder().codecRegistry(pojoCodecRegistry).applyConnectionString(new ConnectionString(linkUrl)).build();MongoClient client = MongoClients.create(build);

2.批量写入对象数据

  public static void write(MongoClient client, String databaseName, String collectionName, List<?> dataList) {if (dataList != null && dataList.size() != 0) {MongoDatabase database = client.getDatabase(databaseName);MongoCollection<Document> collection = database.getCollection(collectionName);List<WriteModel<Document>> writes = new ArrayList();Iterator var7 = dataList.iterator();while(var7.hasNext()) {Object data = var7.next();Map<String, Object> dataMap = ObjectToMapUtil.objectToMap(data);writes.add(new InsertOneModel(new Document(dataMap)));}collection.bulkWrite(writes);}}public static Map<String, Object> objectToMap(Object obj) {Map<String, Object> map = new HashMap();try {Class<?> clazz = obj.getClass();for (Field field : clazz.getDeclaredFields()) {field.setAccessible(true);map.put(field.getName(), field.get(obj));}}catch (Exception e){log.info("ObjectToMapUtil.objectToMap 实体类转换成Map失败={}", JSON.toJSONString(e.getMessage()));e.printStackTrace();}return map;}

3.批量更新数据

private void batchUpdateData(MongoCollection<Document> collection, List<POJO> list) {if (CollectionUtil.isEmpty(list)) {return;}List<String> ids = list.stream().map(POJO::get_id).collect(Collectors.toList());List<WriteModel<Document>> writes = new ArrayList();for (int i = 0; i < list.size(); i++) {Object data = list.get(i);String id = ids.get(i);Map<String, Object> dataMap = ObjectToMapUtil.objectToMap(data);UpdateOneModel updateOneModel = new UpdateOneModel(Filters.eq("_id", id), new Document("$set", new Document(dataMap)), (new UpdateOptions()).upsert(true));writes.add(updateOneModel);}collection.bulkWrite(writes);
}

4.查询

4.1.自定义条件封装，二维数组

private Document buildReportQuery(BasicPageBO pageBO) {Document query = new Document();List<List<Condition>> conditions = pageBO.getConditions();if (CollectionUtil.isEmpty(conditions)) {return query;}query = MongoOperateUtil.buildConditions(conditions);return query;}//BasicPageBO是一个灵活的参数对象，里面有分页信息，非常好用//条件参数对象public static class Condition implements Serializable {@ApiModelProperty("字段名")private String field;@ApiModelProperty("操作符，gt,gte,eq等")private String operator;@ApiModelProperty("值")private String value;@ApiModelProperty("逻辑条件,and、or等")private String logic;}public static Document strEq(String field, String value) {return  new Document(field, value);}public static Document buildBson(BasicPageBO.Condition condition) {String operator = condition.getOperator();switch (operator) {case "eq" :return MongoOperateUtil.strEq(condition.getField(), condition.getValue());case "ne" :return MongoOperateUtil.strNe(condition.getField(), condition.getValue());case "like" :return MongoOperateUtil.like(condition.getField(), condition.getValue());case "startWith" :return MongoOperateUtil.leftLike(condition.getField(), condition.getValue());case "endWith" :return MongoOperateUtil.rightLike(condition.getField(), condition.getValue());case "in" :return MongoOperateUtil.strIn(condition.getField(), condition.getValue());case "nin" :return MongoOperateUtil.strNin(condition.getField(), condition.getValue());case "isNull" :return MongoOperateUtil.isNull(condition.getField(), null);default: {return null;}}}private static Document strNe(String field, String value) {return new Document(field, new Document("$ne", value));}private static Document isNull(String field, String value) {return new Document(field, value);}public static Document buildConditions(List<List<BasicPageBO.Condition>> conditionAll){Document totalBson = null;for (int i = 0; i < conditionAll.size(); i++) {List<BasicPageBO.Condition> conditions = conditionAll.get(i);Document oneBson = null;String twoLogic = conditions.get(0).getLogic();for (int j = 0; j < conditions.size(); j++) {BasicPageBO.Condition condition = conditions.get(j);String logic = condition.getLogic();//加上前缀condition.setField("dataMap." + condition.getField());//单个构建Document bson = MongoOperateUtil.buildBson(condition);if (0 == j) {oneBson = bson;} else {oneBson = MongoOperateUtil.conditionOn(oneBson, bson, logic);}}if (0 == i) {totalBson = oneBson;} else {totalBson = MongoOperateUtil.conditionOn(totalBson, oneBson, twoLogic);}}return totalBson;}public static Document conditionOn(Document first, Document two, String logic) {BasicDBList list = new BasicDBList();list.add(first);list.add(two);if ("and".equals(logic)) {return new Document("$and", list);} else if("or".equals(logic)) {return new Document("$or", list);}return null;}public static Document strIn(String field, String value) {String[] valueArr = value.split(",");List<String> vList = Arrays.asList(valueArr);String operate = "$in";BasicDBList vBasics = new BasicDBList();vBasics.addAll(vList);return new Document(field, new Document(operate, vBasics));}public static Document strNin(String field, String value) {String[] valueArr = value.split(",");List<String> vList = Arrays.asList(valueArr);String operate = "$nin";BasicDBList vBasics = new BasicDBList();vBasics.addAll(vList);return new Document(field, new Document(operate, vBasics));}public static Document like(String field, String value) {Document dbo = new Document();Pattern pattern = Pattern.compile("^.*" + value+ ".*$", Pattern.CASE_INSENSITIVE);dbo.put(field, pattern);return dbo;}public static Document leftLike(String field, String value) {Document dbo = new Document();Pattern pattern = Pattern.compile("^" + Pattern.quote(value) + ".*", Pattern.CASE_INSENSITIVE);dbo.put(field, pattern);return dbo;}public static Document rightLike(String field, String value) {Document dbo = new Document();Pattern pattern = Pattern.compile(".*" + Pattern.quote(value) + "$", Pattern.CASE_INSENSITIVE);dbo.put(field, pattern);return dbo;}

4.2 单表查询

Document condition = new Document();condition.put(k,v)//加各种条件计数 db.getCollection(表名).countDocuments(condition)分页查询 db.getCollection(表名).find(condition).skip(skip).limit(pageSize);

4.3 多表lookup关联查询(大数据量时，已经放弃，分页查询求count时性能极慢(30w数据，耗时30秒左右))

4.3.1 执行的各个阶段
$l oo k u p - >$ match-> $g ro u p - >$ sort-> $u n w in d - >$ project-> $s ki p - >$ limit
leftjoin用到$unwind preserveNullAndEmptyArrays: true

	4.3.2 如下是一个案例：

	int current = (int) pageBO.getCurrent();int pageSize = (int) pageBO.getSize();int skip = pageSize * (current - 1);//以key(某个字段)关联String joinField = "key";//注意，这个字段名需要与返回数据对象中的(关联对象）属性名称对应，不然json解析不出数据String tableAlias = "linkDto";// 联合查询条件List<Bson> aggregationList = new LinkedList<Bson>();//主表查询条件Bson matchFilter = Aggregates.match(match);aggregationList.add(matchFilter);//从表名、主表连接字段、从表连接字段、别名aggregationList.add(Aggregates.lookup(param.getTableId(), joinField, joinField, tableAlias));BasicDBObject bson = new BasicDBObject();bson.put(statusKey, param.getStatus);aggregationList.add(Aggregates.unwind("$linkDto", new UnwindOptions().preserveNullAndEmptyArrays(true)));aggregationList.add(Aggregates.match(bson));List<Bson> countBson = new ArrayList<>(aggregationList);countBson.add(Aggregates.group("_id", new BsonField("count", new BasicDBObject("$sum", 1))));//分组聚会统计数量AggregateIterable<Document> countAgg = util.getDb().getCollection(表名).aggregate(countBson).batchSize(1);long total = 0;Document first = countAgg.first();if (Objects.nonNull(first) && Objects.nonNull(first.get("count"))) {total = (long) (Integer) first.get("count");}aggregationList.add(Aggregates.skip(skip));aggregationList.add(Aggregates.limit(pageSize));AggregateIterable<Document> labelList = util.getDb().getCollection(表名).aggregate(aggregationList);//提取和转换结果集for (Document dr : labelList) {dr.toJson();//todo .....}PageDto<POJOView> pageBean = new PageDto<>();pageBean.setTotal(total);pageBean.setRecords(results);pageBean.setCurrent(current);pageBean.setSize(pageSize);

		## 5.命令行相关查询(直接放到navicat上执行)例子1,总数```javascriptdb.getCollection("主表名").aggregate([{$lookup: {from: "从表名", // 关联的集合名称localField: "key", // 本地字段，主表关联字段，建索引也没有卵用 集合中用于关联的字段foreignField: "key", // 外部字段，从表关联字段 集合中用于关联的字段， 意思是主表key=从表key，若不是相等，可以用管线的形式（构建其他条件，最后别用，真是难用）as: "report" // 关联结果存放的字段名}},{$unwind: {path: "$report",preserveNullAndEmptyArrays: true // 保留没有匹配的订单文档}},{ $match : { "report.字段a":"xxx",$or: [{ "report.字段b": "aaa" }]}},{$group: {_id:null,count:{$sum:1}}},{$project: {count:1}}])

例子2，关联查询list数据

db.getCollection("主表名").aggregate([{$lookup: {from: "从表名", // 关联的集合名称localField: "主表关联key", // 本地字段，orders 集合中用于关联的字段foreignField: "从表关联key", // 外部字段，customers 集合中用于关联的字段as: "report" // 关联结果存放的字段名}},{$unwind: {path: "$report",preserveNullAndEmptyArrays: true // 保留没有匹配的订单文档}},{ $match : { "report.字段a":"xxx",$or: [{ "report.字段b": "xxxc" }]}},{$project: {_id: 1,主表字段a:1,主表字段b:1,report: {_id: "$report._id",......}}},{$skip: 0 // 跳过的文档数，用于分页},{$limit: 10 // 限制返回的文档数，用于分页}])

6.其他

6.1 可视化工具，MongoDB Compass,实用又好用，查看，编辑，导入导出，下载地址https://www.mongodb.com/try/download/compass
6.2 navicat可以执行命令，查询数据选择行模式
6.3 springboot项目，打印命令行参数(参考)，yml或properties中配置logging.level.root debuglogging.level.org.springframework.data.mongodb.core: debug6.4分片集群分片集群部署https://blog.csdn.net/github_38616039/article/details/134158118分配数据创建sh.enableSharding("库名")db.getCollection(表名).createIndex({ fieldName: 1 })sh.shardCollection('库名.表名',{pkValue:1})db.adminCommand("flushRouterConfig")sh.enableBalancing("库名.表名")sh.startBalancer() sh.status({"verbose":1})db.表名.getShardDistribution()

7.参考网站

http://www.manongjc.com/detail/33-nlyyuqqbufycepj.html
https://www.mongodb.com/docs/manual/reference/operator/aggregation/count/
https://www.mongodb.com/docs/manual/reference/operator/aggregation/lookup/?_ga=2.167579261.2108825086.1710915715-66292563.1709890069
https://www.jb51.net/program/285486kdm.htm#_lab2_2_5
https://blog.csdn.net/superatom01/article/details/135004991?spm=1001.2014.3001.5506
https://www.knowledgedict.com/tutorial/mongodb-create-index.html