update document in mongodb using java

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update document in mongodb using java:
　　Mongodb driver provides functionality to update document in mongodb using java. Update is a process in which single or multiple documents can be updated based on certain criteria. Let us see what javadoc says about update

12<a>                       <a>Update a single document in the collection according to the specified arguments.Parameters:filter – a document describing the query filter, which may not be null.update – a document describing the update, which may not be null. The update to apply must include only update operators.Returns:the result of the update one operation

　　Let us try to understand with an example. To update document in mongodb using java, consider we have below document in collection.
123456{    "_id" : ObjectId("55daa2f7e60dd21204306b77"),    "name" : "Harish Taware",    "salary" : 40000,    "type" : "FT"}　　Now we want to update the salary to 80000. We have to provide

• A document which will>
  
• A document which will specify the “$set” operation and the value which will itself be a Document.
  

　　Consider below code
1234Bson filter = new Document("name", "Harish Taware");Bson newValue = new Document("salary", 90000);Bson updateOperationDocument = new Document("$set", newValue);collection.updateOne(filter, updateOperationDocument);　　Here,

• filter variable stores the document with name Harish Taware
  
• newValue is the document which specifies salary needs to be updated to 90000
  
• updateOperationDocument specifies that a set operation is to be performed.
  
• collection.updateOne(filter,updateOperationDocument)  actually does the job of updating document.
  

　　Here is complete code
123456789101112131415161718192021222324252627282930package com.thejavageek.mongodb; import java.util.ArrayList;import java.util.List; import org.bson.Document;import org.bson.conversions.Bson; import com.mongodb.MongoClient;import com.mongodb.client.MongoCollection;import com.mongodb.client.MongoDatabase; public>  public static void main(String[] args) {  MongoClient client = new MongoClient("localhost", 27017); MongoDatabase database = client.getDatabase("employee_db"); MongoCollection<Document> collection = database .getCollection("employees");  Bson filter = new Document("name", "Harish Taware"); Bson newValue = new Document("salary", 90000); Bson updateOperationDocument = new Document("$set", newValue); collection.updateOne(filter, updateOperationDocument);  client.close();  }}　　Run the program to update mongodb document using java. Notice the salary is changed
     Java 123456{    "_id" : ObjectId("55daa2f7e60dd21204306b77"),    "name" : "Harish Taware",    "salary" : 90000,    "type" : "FT"}　　Just like updateOne, we have updateMany() method to update multiple documents at once. I hope the article helped understand how to update document in mongodb using java.