MongoDB学习03之JAVA简单操作增删改查

       经过前面几篇博文的学习，对MongoDB已经有一定的了解了，现在用JAVA来操作MongoDB,进行一些简单的增删改查，查询有复杂查询，这里不一一列举，同学自己看看API就OK了。

      MongoDB JAVA驱动下载：https://github.com/mongodb/mongo-java-driver/downloads

Student.java

package com.fei;public class Student {private int id;private String name;private int age;private int height;public Student() {}public Student(int id, String name, int age, int height) {super();this.id = id;this.name = name;this.age = age;this.height = height;}public int getId() {return id;}public void setId(int id) {this.id = id;}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 int getHeight() {return height;}public void setHeight(int height) {this.height = height;}public String toString(){return "student["+"id="+id+",name="+name+",age="+age+",height="+height+"]";}}

MongoDBUtil.java

package com.fei;import java.net.UnknownHostException;import com.mongodb.DB;import com.mongodb.DBCollection;import com.mongodb.Mongo;public class MongoDBUtil {private final static String IP = "127.0.0.1";private final static int PORT = 27017;private final static String DBNAME = "school";private   Mongo mg = null;private   DB db = null;private  DBCollection  collection= null;private MongoDBUtil(){};public static MongoDBUtil getInstance(){return new MongoDBUtil();}public DBCollection getDBConllection(String collectionName){init();collection = db.getCollection(collectionName);return collection;}private  void init(){try {mg = new Mongo(IP,PORT);} catch (UnknownHostException e) {e.printStackTrace();throw new RuntimeException("mongo连接失败！");}db = mg.getDB(DBNAME);}public  void destory(){if(mg != null)mg.close();db = null;collection = null;}}

StudentDaoImpl.java

package com.fei;import java.util.ArrayList;import java.util.List;import com.mongodb.BasicDBObject;import com.mongodb.DBCollection;import com.mongodb.DBCursor;import com.mongodb.DBObject;public class StudentDaoImpl {private final static String COLLECTION_NAME = "student";private final static String[] FIELDS = new String[]{"_id","name","age","height"};private MongoDBUtil dbUtil = null;public List<Student> queryAll(){List<Student> students = new  ArrayList<Student>();DBCollection collection = getDBCollection();DBCursor cursor = collection.find();while(cursor.hasNext()){DBObject dbObject = cursor.next();students.add(convert(dbObject));}destory();return students;}    public void add(Student s){    DBObject o = new BasicDBObject();    o.put(FIELDS[0],s.getId());    o.put(FIELDS[1], s.getName());    o.put(FIELDS[2], s.getAge());    o.put(FIELDS[3], s.getHeight());        DBCollection collection = getDBCollection();    //insert 与 save的区别，如果_id已存在，使用insert会报错，使用save，则新的替换旧的    //collection.insert(o);    collection.save(o);    destory();    }public void update(Student s){DBObject q = new BasicDBObject();q.put(FIELDS[0],s.getId());DBObject o = new BasicDBObject();    o.put(FIELDS[1], s.getName());    o.put(FIELDS[2], s.getAge());    o.put(FIELDS[3], s.getHeight());        DBCollection collection = getDBCollection();    collection.update(q, o);    destory();}    public void remove(int id){    DBCollection collection = getDBCollection();    DBObject o = new BasicDBObject();    o.put(FIELDS[0], id);    collection.remove(o);    destory();    }        private DBCollection getDBCollection(){    if(dbUtil == null){    dbUtil = MongoDBUtil.getInstance();    }    return dbUtil.getDBConllection(COLLECTION_NAME);    }private Student convert(DBObject dbObject){if(! isStudent(dbObject)){return null;}Student s = new Student();s.setId(Double.valueOf(dbObject.get(FIELDS[0]).toString()).intValue());s.setName(dbObject.get(FIELDS[1]).toString());s.setAge(Double.valueOf(dbObject.get(FIELDS[2]).toString()).intValue());s.setHeight(Double.valueOf(dbObject.get(FIELDS[3]).toString()).intValue());return s;}private boolean isStudent(DBObject dbObject){for(String field : FIELDS){if(! dbObject.containsField(field)){return false;}}return true;}private void destory(){if(dbUtil != null)dbUtil.destory();}}

dbData.txt

use school;db.createCollection('student');db.student.insert({'_id':1,'name':'貂蝉','age':16,'height':160});db.student.insert({'_id':2,'name':'蔡琰','age':17,'height':165});db.student.insert({'_id':3,'name':'甄宓','age':13,'height':155});db.student.insert({'_id':4,'name':'孙尚香','age':15,'height':160});

MongoDBTest.java

package com.fei;public class MongoDBTest {private static StudentDaoImpl dao = new StudentDaoImpl();public static void main(String[] args) {queryAll();Student s = new Student(10,"赵飞燕",16,170);add(s);queryAll();s.setAge(15);s.setHeight(165);update(s);queryAll();remove(10);queryAll();}private static void queryAll(){System.out.println("=======查询全部学生========");for(Student s : dao.queryAll()){System.out.println(s);}}private static void add(Student s){System.out.println("=======新增学生========");System.out.println(s);dao.add(s);}private static void update(Student s){System.out.println("=======修改学生=======");System.out.println(s);dao.update(s);}private static void remove(int id){System.out.println("=======删除学生=====");System.out.println("学生id="+id);dao.remove(id);}}

运行结果图：

源代码下载