Example analysis of common methods of connecting MongoDB in Java
1. Java link to MongoDB
1. Import the Mongo driver package
2. Get the Mongo link object
MongoClient mc = new MongoClient("localhost",27017);
3. Close the link
mc.close();
2. View the library and view the collection
1. Get the library object
MongoDatabase db = mc.getDatabase("myschool");
2. Get the collection of tables in the library
MongoIterable<String> listCollectionNames = db.listCollectionNames(); MongoCursor<String> iterator = listCollectionNames.iterator(); while (iterator.hasNext()) { System.out.println(iterator.next()); }
3 , Java adds, deletes and modifies MongoDB query
1. Add data
a. Add one piece of data
//创建对象 Student s = new Student(); s.setSid(1); s.setSname("王俊凯"); s.setBirthday(new Date()); s.setSsex("男"); s.setClassid(2); //将数据转换为json格式 Gson gson = new GsonBuilder().setDateFormat("yyyy-MM-dd").create(); String json = gson.toJson(s); //获取集合对象 MongoCollection<Document> collection = db.getCollection("student"); //添加一条数据,将json格式转换为document对象 collection.insertOne(Document.parse(json));
b. Add multiple pieces of data
//存入数据 List<Document> dlist=new ArrayList<Document>(); for(int i=0; i<3; i++){ Student s = new Student(); s.setSid(Integer.toString(i+1)); s.setSname("王源"); s.setBirthday(new Date()); s.setSsex("男"); s.setClassid(1); //将数据转换为json格式 Gson gson = new GsonBuilder().setDateFormat("yyyy-MM-dd").create(); String json = gson.toJson(s); dlist.add(Document.parse(json)); } //获取集合对象 MongoCollection<Document> collection = db.getCollection("student"); //添加多条数据 collection.insertMany(dlist);
2. Delete data
a. Delete one piece of data
//获取集合对象 MongoCollection<Document> collection = db.getCollection("student"); Student s = new Student(); s.setSid(1); Gson gson = new GsonBuilder().setDateFormat("yyyy-MM-dd").create(); Bson bson = Document.parse(gson.toJson(s)); DeleteResult deleteOne = collection.deleteOne(bson);
b. Delete multiple pieces of data
//获取集合对象 MongoCollection<Document> collection = db.getCollection("student"); Student s = new Student(); s.setSname("王源"); Gson gson = new GsonBuilder().setDateFormat("yyyy-MM-dd").create(); Bson bson = Document.parse(gson.toJson(s)); DeleteResult deleteMany = collection.deleteMany(bson);
3. Modify data
a. Modify one piece of data
MongoCollection<Document> collection = db.getCollection("student"); //一个条件对象 Bson eq = Filters.eq("sname","易烊千玺"); //要修改的数据 Document doc = new Document(); doc.put("$set", new Document("age",22)); UpdateResult updateone = collection.updateOne(eq, doc); System.out.println(updateone);
b. Modify multiple pieces of data
MongoCollection<Document> collection = db.getCollection("student"); //多条件 Bson bson = Filters.and(Filters.gte("age", 20),Filters.lte("age", 40)); //要修改的数据 Document doc = new Document(); doc.put("$set", new Document("sex","男")); UpdateResult updateMany = collection.updateMany(bson, doc); System.out.println(updateMany);
4. Query data
a. Search all
MongoCollection<Document> collection = db.getCollection("student"); FindIterable<Document> findAll = collection.find(); MongoCursor<Document> iterator = findAll.iterator(); while(iterator.hasNext()){ System.out.println(iterator.next()); }
b. Query with conditions
MongoCollection<Document> collection = db.getCollection("student"); //一个条件对象 Bson eq = Filters.eq("sname","易烊千玺"); FindIterable<Document> findOne = collection.find(eq); MongoCursor<Document> iterator = findOne.iterator(); while(iterator.hasNext()){ System.out.println(iterator.next()); }
c. Fuzzy query
MongoCollection<Document> collection = db.getCollection("student"); //使用正则表达式进行模糊查找 Bson eq = Filters.regex("sname","易"); FindIterable<Document> find = collection.find(eq); MongoCursor<Document> iterator = find.iterator(); while(iterator.hasNext()){ System.out.println(iterator.next()); }
d. Paging query
MongoCollection<Document> collection = db.getCollection("student"); //分页查询 FindIterable<Document> find = collection.find().skip(2).limit(3); MongoCursor<Document> iterator = find.iterator(); while(iterator.hasNext()){ System.out.println(iterator.next()); }
e. Sorting query
MongoCollection<Document> collection = db.getCollection("student"); //排序查询 1升序 -1降序 Bson bson = new Document("sid",1); FindIterable<Document> find = collection.find().sort(bson); MongoCursor<Document> iterator = find.iterator(); while(iterator.hasNext()){ System.out.println(iterator.next()); }
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