mongodb-java-driver基本用法

1、先下载mongodb-java-driver ，可以百度搜索maven仓库的mongoDB的java语言的driver。

2、下面是基本的CRUD示例代码:

import com.google.gson.Gson;
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;

import java.net.UnknownHostException;
import java.util.Calendar;
import java.util.Date;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import org.junit.Test;

public class TestMongoDriver {

    @Test
    public void testCRUD() throws UnknownHostException {
        // 连接到mongodb
        Mongo mongo = new Mongo("localhost", 27017);

        // 打开数据库test
        DB db = mongo.getDB("test");

        // 遍历所有集合的名字
        Set<String> colls = db.getCollectionNames();
        for (String s : colls) {
            System.out.println(s);
            // 先删除所有Collection(类似于关系数据库中的"表")
            if (!s.equals("system.indexes")) {
                db.getCollection(s).drop();
            }
        }

        // 取得集合emp(若：emp不存在，mongodb将自动创建该集合)
        DBCollection coll = db.getCollection("emp");

        // delete all
        DBCursor dbCursor = coll.find();
        for (DBObject dbObject : dbCursor) {
            coll.remove(dbObject);
        }

        // create
        BasicDBObject doc = new BasicDBObject("name", "杨俊明").append("sex", "男")
                .append("address",
                        new BasicDBObject("postcode", "201202").append(
                                "street", "田林路888号").append("city", "上海"));
        coll.insert(doc);

        // retrieve
        BasicDBObject docFind = new BasicDBObject("name", "杨俊明");
        DBObject findResult = coll.findOne(docFind);
        System.out.println(findResult);

        // update
        doc.put("sex", "MALE");// 把sex属性从"男"，改成"MALE"
        coll.update(docFind, doc);
        findResult = coll.findOne(docFind);
        System.out.println(findResult);

        coll.dropIndexes();// 先删除所有索引
        // create index
        coll.createIndex(new BasicDBObject("name", 1)); // 1代表升序

        // 复杂对象
        UserData userData = new UserData("jimmy", "123456");
        Set<String> pets = new HashSet<String>();
        pets.add("cat");
        pets.add("dog");
        Map<String, String> favoriteMovies = new HashMap<String, String>();
        favoriteMovies.put("dragons", "Dragons II");
        favoriteMovies.put("avator", "Avator I");
        userData.setFavoriteMovies(favoriteMovies);
        userData.setPets(pets);
        userData.setBirthday(getDate(1990, 5, 1));
        BasicDBObject objUser = new BasicDBObject("key", "jimmy").append(
                "value", toDBObject(userData));
        coll.insert(objUser);
        System.out.println(coll.findOne(objUser));
    }

    /**
     * 将普通Object对象转换成mongodb的DBObject对象
     * 
     * @param obj
     * @return
     */
    private DBObject toDBObject(Object obj) {
        Gson gson = new Gson();
        String json = gson.toJson(obj);
        return (DBObject) JSON.parse(json);
    }

    /**
     * 获取指定日期
     * 
     * @param year
     * @param month
     * @param day
     * @return
     */
    private Date getDate(int year, int month, int day) {
        Calendar calendar = Calendar.getInstance();
        calendar.clear();
        calendar.set(year, month - 1, day);
        return calendar.getTime();

    }

}

　　其中，为了演示复杂对象的持久化，类UserData定义如下：　

import java.io.Serializable;
import java.util.Date;
import java.util.Map;
import java.util.Set;

public class UserData implements Serializable {

    private static final long serialVersionUID = -4770493237851400594L;
    private String userName;
    private String password;
    private Set<String> pets;
    private Map<String, String> favoriteMovies;
    private Date birthday;

    public UserData() {
    }
    public UserData(String userName, String passWord) {
        this.userName = userName;
        this.password = passWord;
    }
    public String getUserName() {
        return userName;
    }
    public void setUserName(String userName) {
        this.userName = userName;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public Set<String> getPets() {
        return pets;
    }
    public void setPets(Set<String> pets) {
        this.pets = pets;
    }
    public Map<String, String> getFavoriteMovies() {
        return favoriteMovies;
    }
    public void setFavoriteMovies(Map<String, String> favoriteMovies) {
        this.favoriteMovies = favoriteMovies;
    }
    public Date getBirthday() {
        return birthday;
    }
    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }
}

　　运行效果如下：

emp
system.indexes
{ "_id" : { "$oid" : "53d34795744ec171e7f6980a"} , "name" : "杨俊明" , "sex" : "男" , "address" : { "postcode" : "201202" , "street" : "田林路888号" , "city" : "上海"}}
{ "_id" : { "$oid" : "53d34795744ec171e7f6980a"} , "name" : "杨俊明" , "sex" : "MALE" , "address" : { "postcode" : "201202" , "street" : "田林路888号" , "city" : "上海"}}
{ "_id" : { "$oid" : "53d34796744ec171e7f6980b"} , "key" : "jimmy" , "value" : { "userName" : "jimmy" , "password" : "123456" , "pets" : [ "cat" , "dog"] , "favoriteMovies" : { "dragons" : "Dragons II" , "avator" : "Avator I"} , "birthday" : "May 1, 1990 12:00:00 AM"}}