Java对MongoDB的增删改查

package lesson01;

import com.google.gson.Gson;
import com.mongodb.MongoClient;
import com.mongodb.client.FindIterable;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;
import com.mongodb.client.model.Filters;
import org.bson.Document;

public class demo01_Connect_MongoDB {

    public static void main(String[] args) {
        CRUD crud = new CRUD();
        crud.Find2();
    }

    static class CRUD {

        public MongoCollection<Document> connect() {
            //  1.连接到指定的MongoDB数据库，如果不设置host和port，则自动连接localhost:27017
            MongoClient client = new MongoClient("localhost",27017);
            //  2.连接到指定的数据库
            MongoDatabase testDB = client.getDatabase("test");
            //  3.获取指定的集合对象
            MongoCollection<Document> stuColl = testDB.getCollection("students");
            return stuColl;
        }

        public void Insert() {  //  将java中的对象插入
            MongoCollection<Document> stuColl = connect();
            //  4.创建一个学生对象
            Student stu = new Student("猪八戒", 28, "男");
            //  5.将stu转换为JSON
            Gson gson = new Gson();
            String stuJSON = gson.toJson(stu);
            //  6.将json转换为document
            Document doc = Document.parse(stuJSON);
            //  7.将stu对象插入到数据库中
            stuColl.insertOne(doc);
        }

        public void Find() {
            MongoCollection<Document> stuColl = connect();
            //  4.查询数据库中的文档
            Document doc = stuColl.find().first();
            Gson gson = new Gson();
            Student stu = gson.fromJson(doc.toJson(), Student.class);
            System.out.println(stu);
        }

        public void Find2() {
            MongoCollection<Document> stuColl = connect();
            //  4.查询数据库中的文档
            FindIterable<Document> docs = stuColl.find(Filters.eq("name", "猪八戒"));
            for (Document doc : docs) {
                System.out.println(doc.toJson());
            }
        }

        public void Remove() {
            MongoCollection<Document> stuColl = connect();
            stuColl.deleteOne(Filters.eq("name", "猪八戒"));
        }

        public void updateOne() {
            MongoCollection<Document> stuColl = connect();
            stuColl.updateOne(Filters.eq("name", "猪八戒"), new Document("$set", new Document("age", 20)));
        }

    }

    static class Student {
        String name;
        int age;
        String gender;

        public Student(String name, int age, String gender) {
            this.name = name;
            this.age = age;
            this.gender = gender;
        }

        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }

        public int getAge() {
            return age;
        }

        public void setAge(int age) {
            this.age = age;
        }

        public String getGender() {
            return gender;
        }

        public void setGender(String gender) {
            this.gender = gender;
        }

        @Override
        public String toString() {
            return "Student{" +
                    "name='" + name + '\'' +
                    ", age=" + age +
                    ", gender='" + gender + '\'' +
                    '}';
        }
    }

}