Java操作mongodb增删改查的基本操作
1、在项目中引入MongoDB驱动包2、创建类，执行以下步骤2.1.获取连接对象：【MongoClient mc = new MongoClient("localhost",27017);】2.2.获取并创建库对象：【MongoDatabase db = mc.getDatabase("myschool");】
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目录
一、java操作MongoDB数据库的基本步骤
1、在项目中引入MongoDB驱动包
2、在MongoDB数据库中创建myschool集合。【db.createCollection("student");】
3、创建类，执行以下步骤
3.1.获取连接对象：【MongoClient mc = new MongoClient("localhost",27017);】
3.2.获取并创建库对象：【MongoDatabase db = mc.getDatabase("myschool");】
3. 3.获取并创建集合对象：【MongoCollection<Document> collection = db.getCollection("student");】
3. 4.关闭mc.close()；
对于后续方便操作我们可以将其封装起来【写成一个MongoDBUtil.java文件】
package com.ape.dao;
import com.mongodb.MongoClient;
import com.mongodb.client.MongoDatabase;
public class MongoUtil {
private static MongoClient mongoClient;
public static MongoDatabase getDB() {
MongoClient mongoClient = new MongoClient("localhost",27017);
MongoDatabase database = mongoClient.getDatabase("bookComm");
return database;
}
public static void closeMongo() {
if(mongoClient != null) {
mongoClient.close();
}
}
}
二、操作MongoDB数据库—— insert数据
语法：collection.insertOne(document);//一次添加一条数据
collection.insertMany(list);//一次添加多条记录
具体实例如下
1.创建学生实体类
package com.shang.Bean;
import java.util.Date;
public class Student {
private Date birthday;
private String name;
private String sex;
private int age;
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date date) {
this.birthday = date;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public Student() {
super();
// TODO Auto-generated constructor stub
}
public Student(Date birthday, String name, String sex, int age) {
super();
this.birthday = birthday;
this.name = name;
this.sex = sex;
this.age = age;
}
@Override
public String toString() {
return "Student [birthday=" + birthday + ", name=" + name + ", sex=" + sex + ", age=" + age + "]";
}
}
2.创建测试类
@SuppressWarnings("resource")
public static void main(String[] args) {
//1.获取MongoDB的连接对象
MongoClient mc = new MongoClient("localhost",27017);
System.out.println(mc);
//查看数据库中所有的库 数据库连接对象.listDatabaseNames();得到一个iterator，遍历
MongoIterable<String> listDatabaseNames = mc.listDatabaseNames();
MongoCursor<String> iterator = listDatabaseNames.iterator();
while(iterator.hasNext()) {
String next = iterator.next();
System.out.println(next);
}
//2.获得库对象： 数据库连接对象.getDatabase("数据库名")
MongoDatabase db = mc.getDatabase("myschool");
System.out.println(db);
//取到库中的集合 ：库对象.listCollectionNames(); 遍历
MongoIterable<String> listCollectionNames = db.listCollectionNames();
for(String str:listCollectionNames) {
System.out.println(str);
}
//3.获取对象
MongoCollection<Document> collection = db.getCollection("student");
System.out.println();
//新增
Document document = new Document();
document.put("name", "张瑜");
document.put("birthday", "2022-9-13");
document.put("sex", "男");
document.put("age", "18");
//添加一条数据，没有返回值
collection.insertOne(document);
//添加多条数据
Document document1 = new Document();
document1.put("name", "张瑜");
document1.put("birthday", "2022-9-13");
document1.put("sex", "男");
document1.put("age", "18");
Document document2 = new Document();
document2.put("name", "婳樱");
document2.put("birthday", "2022-9-13");
document2.put("sex", "女");
document2.put("age", "18");
Document document3 = new Document();
document3.put("name", "王黎");
document3.put("birthday", "2022-9-13");
document3.put("sex", "男");
document3.put("age", "18");
Document document4 = new Document();
document4.put("name", "张瑜");
document4.put("birthday", "2022-9-13");
document4.put("sex", "男");
document4.put("age", "18");
Document document5 = new Document();
document5.put("name", "张瑜");
document5.put("birthday", "2022-9-13");
document5.put("sex", "男");
document5.put("age", "18");
ArrayList<Document> list =new ArrayList<>();
list.add(document1);
list.add(document2);
list.add(document3);
list.add(document4);
list.add(document5);
collection.insertMany(list);
三、操作MongoDB数据库—— delete数据
语法： collection.deleteOne(new Document("name","张瑜"));//一次删除一条数据
collection.updateMany(eq, new Document("$set",new Document("age",20)));;//一次删除多条记录
具体实例如下
Bson gt = Filters.gt("age", 100);
Bson exists = Filters.exists("sex");
Bson exists2 = Filters.exists("sex", false);
//一次删除一条数据
DeleteResult deleteOne = collection.deleteOne(new Document("name","张瑜"));
System.out.println(deleteOne);
DeleteResult deleteOne2 = collection.deleteMany(gt);
System.out.println(deleteOne2);
//一次删除多条数据
DeleteResult deleteMany = collection.deleteMany(exists2);
System.out.println(deleteMany);关于过滤器，bson的解释
学习过滤器Filters：该过滤器为所有的MongoDB的查询操作静态工厂方法。每个方法返回BSON类型，又可以传递给期望查询锅过滤器的任何一个方法的实例。【Bson eq = Filters.eq("name","张瑜");
四、操作MongoDB数据库—— update数据
语法： collection.updateOne(eq, new Document("$set",new Document("age",21)));//一次更新一条数据
collection.updateMany(eq, new Document("$set",new Document("age",20)));;//一次更新多条记录
具体实例如下
//修改[学习过滤器Filters]
Bson eq = Filters.eq("name","张瑜");
//一次更新一条数据
UpdateResult updateOne = collection.updateOne(eq, new Document("$set",new Document("age",21)));
System.out.println(updateOne);
//输出结果matchedCount=1, modifiedCount=1, upsertedId=null
//一次更新多条数据
UpdateResult updateMany = collection.updateMany(eq, new Document("$set",new Document("age",20)));
System.out.println(updateMany);
//输出结果：matchedCount=7, modifiedCount=1, upsertedId=null
//使upsertid有值【matchedCount=0, modifiedCount=0, upsertedId=BsonObjectId{value=631fe6fdcdfd423e2a54d588}】
UpdateResult updateMany1 = collection.updateMany(eq, new Document("$set",new Document("age",20)),new UpdateOptions().upsert(true));
System.out.println(updateMany1);
//Filters利用and/or方法将多个条件变成一个Bson格式作为条件，年龄大于20，小于等于30的学 生性别改为保密
Bson eq1 = Filters.gte("age",20);
Bson lte = Filters.lte("age", 30);
Bson and = Filters.and(eq1,lte);
UpdateResult updateMany2 = collection.updateMany(and, new Document("$set",new Document("sex","保密")));
System.out.println(updateMany2);
//Inc给文件的字段加上100
UpdateResult updateMany3 = collection.updateMany(and, new Document("$inc",new Document("age",100)));
System.out.println(updateMany3);关于update输出结果的解释【三个输出值的解释】
1、matchedCount 找到的符合条件的记录条数 ，
2、modifiedCount=1 更新的记录条数，
3、upsertedId 如果更新的记录不存在，就会新建一条数据，返回的是新建数据的id号
案例中输出的三个如下，可供参考理解
1、新增一条数据：updateOne();【UpdateResult updateOne = collection.updateOne(eq, new Document("$set",new Document("age",20)));】
输出结果：matchedCount=1, modifiedCount=1, upsertedId=null
2、新增多条数据：uodateMany();【UpdateResult updateMany = collection.updateMany(eq, new Document("$set",new Document("age",20)));】
输出结果：matchedCount=7, modifiedCount=1, upsertedId=null
3、upsertedId：使upsertedId有值，当新增条件不成立的时候，设置这个值，就会新增一条新的数据。【UpdateResult updateMany1 = collection.updateMany(eq, new Document("$set",new Document("age",20)),new UpdateOptions().upsert(true));】
输出结果：matchedCount=0, modifiedCount=0, upsertedId=BsonObjectId{value=631fe6fdcdfd423e2a54d588}
五、操作MongoDB数据库—— find数据
语法： collection.find()//查找所有
collection.updateMany(eq, new Document("$set",new Document("age",20)));;//有条件查询
具体实例如下
//查询find
FindIterable<Document> find = collection.find();
System.out.println(find);
//模糊查询 ^regex$
Bson eq = Filters.regex("name", "张");
FindIterable<Document> findmh = collection.find(eq);
System.out.println(findmh);六、全部代码展示
项目结构【注意一部分一部分测试理解，导入参考驱动包，本项目lib下两个驱动包】
实体类Student
package com.shang.Bean;
import java.util.Date;
public class Student {
private Date birthday;
private String name;
private String sex;
private int age;
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date date) {
this.birthday = date;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
public Student() {
super();
// TODO Auto-generated constructor stub
}
public Student(Date birthday, String name, String sex, int age) {
super();
this.birthday = birthday;
this.name = name;
this.sex = sex;
this.age = age;
}
@Override
public String toString() {
return "Student [birthday=" + birthday + ", name=" + name + ", sex=" + sex + ", age=" + age + "]";
}
}
DaoUtil
package com.shang.Dao;
import java.lang.reflect.Field;
import java.util.Iterator;
import java.util.Set;
import org.bson.Document;
public class DocUtil {
public static <T> Document ObjToDoc(T t){
Document doc = new Document();
Field[] fields = t.getClass().getDeclaredFields();
if(fields != null) {
for(int i = 0; i< fields.length;i++) {
try {
fields[i].setAccessible(true);
String name = fields[i].getName();
Object value = fields[i].get(t);
doc.append(name, value);
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
return doc;
}
public static <T> T DocToObj(Document doc,Class<T> t) {
T obj = null;
try {
obj = t.newInstance();
Set<String> keySet = doc.keySet();
System.out.println(keySet);
Iterator<String> iterator = keySet.iterator();
while (iterator.hasNext()) {
String next = iterator.next();
String keyname = next.toLowerCase();
if(!keyname.equals("_id")) {
Field[] declaredFields = t.getDeclaredFields();
Field declaredField = t.getDeclaredField(keyname);
declaredField.setAccessible(true);
declaredField.set(obj, doc.get(next));
}
}
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
return obj;
}
}
测试文件
package com.shang.test;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import org.bson.Document;
import org.bson.conversions.Bson;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.mongodb.MongoClient;
import com.mongodb.client.FindIterable;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoCursor;
import com.mongodb.client.MongoDatabase;
import com.mongodb.client.MongoIterable;
import com.mongodb.client.model.Filters;
import com.mongodb.client.result.DeleteResult;
import com.shang.Bean.Student;
public class test01 {
@SuppressWarnings("resource")
public static void main(String[] args) {
//1.获取MongoDB的连接对象
MongoClient mc = new MongoClient("localhost",27017);
System.out.println(mc);
//查看数据库中所有的库 数据库连接对象.listDatabaseNames();得到一个iterator，遍历
MongoIterable<String> listDatabaseNames = mc.listDatabaseNames();
MongoCursor<String> iterator = listDatabaseNames.iterator();
while(iterator.hasNext()) {
String next = iterator.next();
System.out.println(next);
}
//2.获得库对象： 数据库连接对象.getDatabase("数据库名")
MongoDatabase db = mc.getDatabase("myschool");
System.out.println(db);
//取到库中的集合 ：库对象.listCollectionNames(); 遍历
MongoIterable<String> listCollectionNames = db.listCollectionNames();
for(String str:listCollectionNames) {
System.out.println(str);
}
//3.获取对象
MongoCollection<Document> collection = db.getCollection("student");
System.out.println();
//新增
Document document = new Document();
document.put("name", "张瑜");
document.put("birthday", "2022-9-13");
document.put("sex", "男");
document.put("age", "18");
//添加一条数据，没有返回值
collection.insertOne(document);
//一次性添加多条数据 insertMany();
Document document1 = new Document();
document1.put("name", "张瑜");
document1.put("birthday", "2022-9-13");
document1.put("sex", "男");
document1.put("age", "18");
Document document2 = new Document();
document2.put("name", "婳樱");
document2.put("birthday", "2022-9-13");
document2.put("sex", "女");
document2.put("age", "18");
Document document3 = new Document();
document3.put("name", "王黎");
document3.put("birthday", "2022-9-13");
document3.put("sex", "男");
document3.put("age", "18");
Document document4 = new Document();
document4.put("name", "张瑜");
document4.put("birthday", "2022-9-13");
document4.put("sex", "男");
document4.put("age", "18");
Document document5 = new Document();
document5.put("name", "张瑜");
document5.put("birthday", "2022-9-13");
document5.put("sex", "男");
document5.put("age", "18");
ArrayList<Document> list =new ArrayList<>();
list.add(document1);
list.add(document2);
list.add(document3);
list.add(document4);
list.add(document5);
collection.insertMany(list);
//修改[学习过滤器Filters]
Bson eq = Filters.eq("name","张瑜");
UpdateResult updateOne = collection.updateOne(eq, new Document("$set",new Document("age",21)));
System.out.println(updateOne);
//输出结果matchedCount=1, modifiedCount=1, upsertedId=null
UpdateResult updateMany = collection.updateMany(eq, new Document("$set",new Document("age",20)));
System.out.println(updateMany);
//输出结果：matchedCount=7, modifiedCount=1, upsertedId=null
//使upsertid有值【matchedCount=0, modifiedCount=0, upsertedId=BsonObjectId{value=631fe6fdcdfd423e2a54d588}】
UpdateResult updateMany1 = collection.updateMany(eq, new Document("$set",new Document("age",20)),new UpdateOptions().upsert(true));
System.out.println(updateMany1);
//Filters利用and/or方法将多个条件变成一个Bson格式作为条件，年龄大于20，小于等于30的学生性别改为保密
Bson eq1 = Filters.gte("age",20);
Bson lte = Filters.lte("age", 30);
Bson and = Filters.and(eq1,lte);
UpdateResult updateMany2 = collection.updateMany(and, new Document("$set",new Document("sex","保密")));
System.out.println(updateMany2);
//Inc给文件的字段加上100
UpdateResult updateMany3 = collection.updateMany(and, new Document("$inc",new Document("age",100)));
System.out.println(updateMany3);
//删除
Bson gt = Filters.gt("age", 100);
Bson exists = Filters.exists("sex");
Bson exists2 = Filters.exists("sex", false);
DeleteResult deleteOne = collection.deleteOne(new Document("name","张瑜"));
System.out.println(deleteOne);
DeleteResult deleteOne2 = collection.deleteMany(gt);
System.out.println(deleteOne2);
DeleteResult deleteMany = collection.deleteMany(exists2);
System.out.println(deleteMany);
Student s=new Student();
s.setAge(20);
s.setBirthday(new Date());
s.setSex("男");
s.setName("十四");
//JSON格式的转换
Gson gson=new GsonBuilder().create();
Document document1 = new Document();
//将student对象转换为JSON格式
String json=gson.toJson(s);
//以JSON的格式将数据加入到MongoDB数据库中
collection.insertOne(Document.parse(json));
//查询find
FindIterable<Document> find = collection.find();
System.out.println(find);
//模糊查询 ^regex$
Bson eq = Filters.regex("name", "张");
FindIterable<Document> findmh = collection.find(eq);
System.out.println(findmh);
//分页skip();
Document document = new Document("birthday",-1);
FindIterable<Document> find1= collection.find(eq).sort(document);
for (Document doc :find1) {
System.out.println(doc);
}
List<Student> slist=new ArrayList<>();
MongoCursor<Document> iterator2 = find.iterator();
Student s1=new Student();
Document next = iterator2.next();
s1.setSex("男");
s1.setBirthday(new Date());
s1.setAge(20);
s.setName("花火");
//参数一 JSON 字符串
// 参数二 需要的对象的类型
json=next.toJson();
System.out.println(json);
gson.fromJson(json, Student.class);
slist.add(s1);
for(Student ss:slist) {
System.out.println(ss);
}
mc.close();
}
}
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