MongoDB-Java进行增删改查-优快云博客

本文介绍如何使用 Java 对 MongoDB 进行基本的增删改查操作，包括连接数据库、获取集合、读取数据、删除记录、添加新记录及更新记录等步骤。

MongoDB-Java进行增删改查

总结：

操作总结:
1.步骤：创建实例(Mongo)-->获取数据库(DB)-->获取集合(table)(DBCollection)-->获取集合中的数据(DBCursor)
        -->对数据进行操作
 2.无表概念, 集合取代。

代码案例：

package mongo.util;

import java.net.UnknownHostException;
import com.mongodb.BasicDBObject;
import com.mongodb.DB;
import com.mongodb.DBCollection;
import com.mongodb.DBCursor;
import com.mongodb.DBObject;
import com.mongodb.Mongo;
import com.mongodb.util.JSON;

public class MonUtil {
/**
 * Mongodb java操作CRUD
 * @param args
 * @throws UnknownHostException 
 */

/**
 * 操作总结:
 * 1.步骤：创建实例(Mongo)-->获取数据库(DB)-->获取集合(table)(DBCollection)-->获取集合中的数据(DBCursor)
 *        -->对数据进行操作
 * 2.无表概念, 集合取代。
 */
public static void main(String[] args) throws UnknownHostException {
	      //创建一个Mongo实例，默认使用本地"127.0.0.1",端口27017
	      //Mongo mongo1= new Mongo();
              //使用IP+端口号创建 实例
	       Mongo mongo02 = new Mongo("127.0.0.1",27017);
		//得到所有数据库的名称
		for(String name:mongo02.getDatabaseNames()){
			System.out.println("dbName: "+name);
		}
		
	    //取得某个数据库，用于后续对数据库的操作
		DB db = mongo02.getDB("mymongo");
		
		//获取所有的集合
		System.out.println("遍历所有的集合");
		for(String name: db.getCollectionNames()){
			System.out.println("collectionName: "+name);
		}
		//获取对应的集合
		DBCollection users = db.getCollection("sys_user");
		
		//获取集合中的数据
		DBCursor cur = users.find();
		//遍历集合中的所有内容
		System.out.println("遍历集合中的内容：");	
		while(cur.hasNext()){
		   System.out.println(cur.next());	
		}
		System.out.println("cur.count(): " + cur.count());
		System.out.println("cur.getCursorId(): " + cur.getCursorId());
		System.out.println("JSON.serialize(cur): " + JSON.serialize(cur));
		
		//删除
		users.remove(new BasicDBObject("name","wangshuai"));
		System.out.println("删除--cur.count(): " + cur.count());
		
		//新增
		DBObject user1 = new BasicDBObject(); 
		user1.put("name", "dada");
		user1.put("age","28");
		user1.put("sex", "man");
		users.save(user1);
		System.out.println("新增--cur.count(): " + cur.count());
		
		//修改
		DBObject user_update = new BasicDBObject(); 
		user_update.put("name", "wangwu");
		user_update.put("age","18");
		user_update.put("sex", "man");
		users.update(new BasicDBObject("name", "wangwu"),user_update);
		System.out.println("修改--"+JSON.serialize(users.find(new BasicDBObject("name", "wangwu"))));
		System.out.println("遍历所有数据：");
		System.out.println("JSON.serialize(cur): " + JSON.serialize(cur));
	}
}

控制台打印输出：

dbName: KM
dbName: local
dbName: mymongo
dbName: admin
遍历所有的集合
collectionName: sys_user
collectionName: system.indexes
遍历集合中的内容：
{ "_id" : { "$oid" : "5a7409448d2ed42d1280a7c1"} , "name" : "wangwu" , "age" : "18" , "sex" : "man"}
{ "_id" : { "$oid" : "5a74098e8d2e75e7dfc7adbc"} , "name" : "王琦" , "age" : "18" , "sex" : "man"}
{ "_id" : { "$oid" : "5a740a528d2ebd5bc064801f"} , "name" : "chenchen" , "age" : "18" , "sex" : "man"}
{ "_id" : { "$oid" : "5a740af78d2e926c7de492cc"} , "name" : "xuxu" , "age" : "28" , "sex" : "man"}
{ "_id" : { "$oid" : "5a740b2d8d2ede3a44c78876"} , "name" : "niannian" , "age" : "28" , "sex" : "man"}
cur.count(): 5
cur.getCursorId(): 0
JSON.serialize(cur): [ { "_id" : { "$oid" : "5a7409448d2ed42d1280a7c1"} , "name" : "wangwu" , "age" : "18" , "sex" : "man"} , { "_id" : { "$oid" : "5a74098e8d2e75e7dfc7adbc"} , "name" : "王琦" , "age" : "18" , "sex" : "man"} , { "_id" : { "$oid" : "5a740a528d2ebd5bc064801f"} , "name" : "chenchen" , "age" : "18" , "sex" : "man"} , { "_id" : { "$oid" : "5a740af78d2e926c7de492cc"} , "name" : "xuxu" , "age" : "28" , "sex" : "man"} , { "_id" : { "$oid" : "5a740b2d8d2ede3a44c78876"} , "name" : "niannian" , "age" : "28" , "sex" : "man"}]
删除--cur.count(): 5
新增--cur.count(): 6
修改--[ { "_id" : { "$oid" : "5a7409448d2ed42d1280a7c1"} , "name" : "wangwu" , "age" : "18" , "sex" : "man"}]
遍历所有数据：
JSON.serialize(cur): [ { "_id" : { "$oid" : "5a7409448d2ed42d1280a7c1"} , "name" : "wangwu" , "age" : "18" , "sex" : "man"} , { "_id" : { "$oid" : "5a74098e8d2e75e7dfc7adbc"} , "name" : "王琦" , "age" : "18" , "sex" : "man"} , { "_id" : { "$oid" : "5a740a528d2ebd5bc064801f"} , "name" : "chenchen" , "age" : "18" , "sex" : "man"} , { "_id" : { "$oid" : "5a740af78d2e926c7de492cc"} , "name" : "xuxu" , "age" : "28" , "sex" : "man"} , { "_id" : { "$oid" : "5a740b2d8d2ede3a44c78876"} , "name" : "niannian" , "age" : "28" , "sex" : "man"} , { "_id" : { "$oid" : "5a740b778d2e4d08297fc74e"} , "name" : "dada" , "age" : "28" , "sex" : "man"}]