Java语言链接MongoDB常用的方法

一、Java链接MongoDB

1. 导入Mongo驱动包

2. 获取Mongo链接对象

MongoClient mc = new MongoClient("localhost",27017);

3. 关闭链接

mc.close();

二、查看库，查看集合

1. 获取库对象

MongoDatabase db = mc.getDatabase("myschool");

2. 获取库中表的集合

MongoIterable<String> listCollectionNames = db.listCollectionNames();
        
MongoCursor<String> iterator = listCollectionNames.iterator();
    while (iterator.hasNext()) {
        System.out.println(iterator.next());
    }

三、Java对MongoDB增删改查

1. 添加数据

a. 添加一条数据

//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. 添加多条数据

//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. 删除数据

a. 删除一条数据

//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. 删除多条数据

//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. 修改数据

a. 修改一条数据

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. 修改多条数据

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. 查询数据

a. 全查

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. 带条件查询

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. 模糊查询

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. 分页查询

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. 排序查询

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()); 
}