在工作中使用到了MongoDB，平时也看了一些资料，感觉MongoDB官网内develop zone有个不错的manual，很多资料都可以查到，地址如下：http://www.mongodb.org/display/DOCS/Manual
另外，本blog主要记录一下使用mongodb java driver来访问数据库的一些总结。
主要是由createMongoInstance()方法完成初始化工作。
protected static final Mongo mongoInstance = createMongoInstance();
private static Mongo createMongoInstance() {
MongoOptions mo = new MongoOptions();
mo.socketKeepAlive=true;
mo.autoConnectRetry = true;
mo.maxAutoConnectRetryTime=10;
mo.connectionsPerHost = 40;
mo.connectTimeout = 20 * 1000;
mo.socketTimeout = 60 * 1000;
try {
if (DatabaseProject.DB_CONFIG.containsKey("mongodb.ips")) {
return new Mongo(getServerAddrsFromConf("mongodb"),mo);
}
return new Mongo(new ServerAddress(DatabaseProject.DB_CONFIG.getString("mongodb.ip"), DatabaseProject.DB_CONFIG.getInt("mongodb.port")),mo);
} catch (Throwable e) {
DatabaseProject.LOGGER.error("Failed to init mongodb", e);
throw new ExceptionInInitializerError(e);
}
}
其中有一些数据库配置直接写在配置文件里了，在MongoJavaDriverDAO中初始化一部分数据：
public void insertCollData(){
//如果该collection不存在则会自动创建
DBCollection parentcoll = getCollection("ParentColl");
DBCollection childcoll = getCollection("ChildColl");
for(int i=0;i<1000;i++){
DBObject document = new BasicDBObject();
document.put("intData", 1000+i);
document.put("longData", System.currentTimeMillis());
document.put("strData", UUID.randomUUID().toString());
document.put("doubleData", 1.123+i);
document.put("createDate", new Date());
document.put("booleanData", true);
DBObject innerDoc = new BasicDBObject();
innerDoc.put("innertype", "string");
innerDoc.put("innerContent", "string"+i);
document.put("documentData", innerDoc);
parentcoll.insert(document);
DBObject childDocument = new BasicDBObject();
childDocument.put("parentId", document.get("_id"));
childDocument.put("createDate", new Date());
List list = new ArrayList();
list.add("str" + i%10);
list.add("str" + i%20);
list.add(new BasicDBObject("arr"+(i%10),(i%10)));
list.add(new BasicDBObject("arr"+(i%20),(i%20)));
childDocument.put("arrays",list);
childcoll.insert(childDocument);
}
System.out.println("ParentColl Count:"+parentcoll.count());
System.out.println("ChildColl Count:"+childcoll.count());
}
其中getCollection方法会获取集合，不存在的话会自动创建一个。getCollection方法如下：
public static DBCollection getCollection(String collectionName){
return getDB().getCollection(collectionName);
}
现在创建了2个集合ParentColl、ChildColl，并初始化了数据。
查询相关方法：
/**
* 查询全部数据
*/
public void findColl(){
coll = getCollection("ParentColl");
DBCursor cur = coll.find();
while(cur.hasNext()){
System.out.println(cur.next());
}
System.out.println("Count:"+coll.count());
}
/**
* 根据ObjectId查询
*/
public void findById(String id){
coll = getCollection("ParentColl");
DBCursor cur = coll.find(new BasicDBObject("_id", new ObjectId(id)));//直接用string查不出来
while(cur.hasNext()){
System.out.println(cur.next());
}
}
/**
* And多条件查询
*/
public void findByAndQuery(int intData,long longData){
coll = getCollection("ParentColl");
BasicDBObject query = new BasicDBObject();
query.put("intData", intData);
query.put("longData", longData);
System.out.println(coll.findOne(query));
}
/**
* OR多条件查询
*/
public void findByORQuery(int lte,int gt,long longData){
coll = getCollection("ParentColl");
BasicDBObject query=new BasicDBObject();
BasicDBObject longdata = new BasicDBObject("longData", longData);
BasicDBObject intdata = new BasicDBObject("intData", new BasicDBObject().append("$gt", gt).append("$lte",lte));
BasicDBList cond=new BasicDBList();
cond.add(longdata);
cond.add(intdata);
query.put("$or", cond);
DBCursor cur = coll.find(query);
while(cur.hasNext()){
System.out.println(cur.next());
}
}
/**
* IN查询
*/
public void findByINQuery(int value1,int value2){
coll = getCollection("ParentColl");
BasicDBObject query=new BasicDBObject();
BasicDBList cond=new BasicDBList();
cond.add(value1);
cond.add(value2);
query.put("intData",new BasicDBObject("$in", cond));
DBCursor cur = coll.find(query);
while(cur.hasNext()){
System.out.println(cur.next());
}
}
/**
* NOT查询
*/
public void findByNotQuery(int value1,int value2){
coll = getCollection("ParentColl");
BasicDBObject query=new BasicDBObject();
BasicDBList cond=new BasicDBList();
cond.add(value1);
cond.add(value2);
query.put("intData",new BasicDBObject("$nin", cond));
System.out.println("Count:"+coll.find(query).count());
}
/**
* 获取结果集第一条
*/
public void fetchFirstQuery(int value1,int value2){
coll = getCollection("ParentColl");
BasicDBList cond = new BasicDBList();
cond.add(value1);
cond.add(value2);
BasicDBObject query = new BasicDBObject().append("intData",new BasicDBObject("$nin",cond));
System.out.println(coll.findOne(query));
}
/**
* 查询文档部分列
*/
public void querySomeKey(){
coll = getCollection("ParentColl");
DBCursor cur = coll.find(new BasicDBObject(),new BasicDBObject("intData",true));
while(cur.hasNext()){
System.out.println(cur.next());
}
}
/**
* 查询内嵌文档
*/
public void queryInnerDocument(){
coll = getCollection("ParentColl");
BasicDBObject map = new BasicDBObject();
map.put("innertype","string");
map.put("innerContent","string0");
DBCursor cur = coll.find(new BasicDBObject("documentData",map));
while(cur.hasNext()){
System.out.println(cur.next());
}
}
/**
* 查询内嵌部分文档
*/
public void querySubInnerDocument(){
coll = getCollection("ParentColl");
DBCursor cur = coll.find(new BasicDBObject("documentData.innerContent","string0"));
while(cur.hasNext()){
System.out.println(cur.next());
}
}
/**
* 查询分页文档
*/
public void queryByPage(int skipNum,int pageNum){
coll = getCollection("ParentColl");
DBCursor cur = coll.find().skip(skipNum).limit(pageNum);
while(cur.hasNext()){
System.out.println(cur.next());
}
}
/**
* 查询文档某列是否存在
*/
public void queryExists(){
coll = getCollection("ParentColl");
DBCursor cur = coll.find(new BasicDBObject("longData",new BasicDBObject("$exists",true)));
while(cur.hasNext()){
System.out.println(cur.next());
}
}
/**
* 查询文档排序
*/
public void sortDocument(){
coll = getCollection("ParentColl");
DBCursor cur = coll.find().sort(new BasicDBObject("intData",-1));//1:asc / -1:desc
while(cur.hasNext()){
System.out.println(cur.next());
}
}
补充distinct查询：
/**
* 获取根据某元素做distinct查询.
*/
public void distinctKey(){
coll = getCollection("ParentColl");
List<String> list = coll.distinct("documentData.innertype");
for(String str:list){
System.out.println(str);
}
}
不难发现主要用到BasicDBObject、BasicDBList、DBCursor这三个类。BasicDBObject好比一个map，好比使用json查询中的{} 。BasicDBList是个list，用于or，nin等条件查询。DBCursor用于遍历结果集。其实只要将对应的json查询使用这3个类转化一下，就能写出对应的java代码了。
更新相关：
/**
* 更新文档1
*/
public void updateDocument(){
DB db = getDB();
//由于mongodb中使用连接池的原因,getLastError()需要再次从连接池中获取连接.
//保证update操作和getLastError()使用同一个连接.
db.requestStart();
coll = db.getCollection("ParentColl");
WriteResult result = coll.update(new BasicDBObject("intData",1100),new BasicDBObject("$set", new BasicDBObject("booleanData",false)));
System.out.println("update count:"+result.getN());
if(result.getLastError().ok()){//获取上次操作结果是否有错误.
System.out.println("update document success.");
}else{
System.out.println(result.getLastError().getErrorMessage());
}
db.requestDone();
}
/**
* 更新文档2
*/
public void updateMultiDocument(){
DB db = getDB();
db.requestStart();
coll = db.getCollection("ParentColl");
//第三个参数:如果没有该文档是否创建,第四个参数:是否更新全部匹配条件的文档.
WriteResult result = coll.update(new BasicDBObject("booleanData",false),new BasicDBObject("$set", new BasicDBObject("booleanData",true)),false,true);
System.out.println("update count:"+result.getN());
if(result.getLastError().ok()){//获取上次操作结果是否有错误.
System.out.println("update document success.");
}else{
System.out.println(result.getLastError().getErrorMessage());
}
db.requestDone();
}
注意requestStart、requestDone方法保证使用同一个数据库连接。WriteResult记录更新结果。
索引相关：
/**
* 创建唯一索引
*/
public void createIndexes(){
coll = getCollection("ParentColl");
BasicDBObject index = new BasicDBObject();
index.put("intData",1);//1:asc / -1:desc
index.put("unique",true);//唯一索引
coll.createIndex(index);
}
/**
* 查询索引信息
*/
public void getIndexes(){
coll = getCollection("ParentColl");
List<DBObject> indexInfo = coll.getIndexInfo();
System.out.println(indexInfo);
}
/**
* 删除索引信息
*/
public void dropIndexes(){
coll = getCollection("ParentColl");
//删除的索引必须跟创建的索引名称\排序\是否唯一都相同才能删除
BasicDBObject index = new BasicDBObject();
index.put("intData",1);
index.put("unique",true);
coll.dropIndex(index);
}
对于文档可能还会对数组操作：
/**
* 取出文档中的数组
*/
public void queryArray(){
coll = getCollection("ChildColl");
DBCursor cur = coll.find(new BasicDBObject(),new BasicDBObject("arrays",1));
while(cur.hasNext()){
BasicDBObject bo = (BasicDBObject)cur.next();
List<BasicDBObject> list = (List<BasicDBObject>)bo.get("arrays");
System.out.println(list.toString());
}
}
/**
* 查询数组内是否包含某元素
*/
public void queryElementInArray(){
coll = getCollection("ChildColl");
BasicDBObject query = new BasicDBObject();
BasicDBObject obj = new BasicDBObject();
obj.put("arr0",0);
query.put("arrays", new BasicDBObject("$elemMatch",obj));
DBCursor cur = coll.find(query);
while(cur.hasNext()){
System.out.println(cur.next());
}
}
/**
* 数组内包含元素的值
*/
public void queryElementArray(){
coll = getCollection("ChildColl");
BasicDBObject obj = new BasicDBObject();
obj.put("arrays", "str0");
obj.put("arrays.arr0",0);
obj.put("arrays.arr10",10);
DBCursor cur = coll.find(obj);
while(cur.hasNext()){
System.out.println(cur.next());
}
}
/**
* push(pushAll) array element
*/
public void pushElementInArray(String _id){
DB db = getDB();
db.requestStart();
coll = getCollection("ChildColl");
//WriteResult result = coll.update(new BasicDBObject("_id", new ObjectId(_id)),new BasicDBObject("$push",new BasicDBObject("arrays",new BasicDBObject("arr99","99"))));
List<BasicDBObject> list=new ArrayList<BasicDBObject>();
list.add(new BasicDBObject("arr99",99));
list.add(new BasicDBObject("arr100",100));
WriteResult result = coll.update(new BasicDBObject("_id", new ObjectId(_id)),new BasicDBObject("$pushAll",new BasicDBObject("arrays",list)));
System.out.println("update count:"+result.getN());
if(result.getLastError().ok()){
System.out.println("update document success.");
}else{
System.out.println(result.getLastError().getErrorMessage());
}
db.requestDone();
}
/**
* pull(pullAll) array element
*/
public void pullElementInArray(String _id){
DB db = getDB();
db.requestStart();
coll = getCollection("ChildColl");
List<BasicDBObject> list=new ArrayList<BasicDBObject>();
list.add(new BasicDBObject("arr99",99));
list.add(new BasicDBObject("arr100",100));
//WriteResult result = coll.update(new BasicDBObject("_id", new ObjectId(_id)),new BasicDBObject("$pull",new BasicDBObject("arrays",new BasicDBObject("arr100",100))));
WriteResult result = coll.update(new BasicDBObject("_id", new ObjectId(_id)),new BasicDBObject("$pullAll",new BasicDBObject("arrays",list)));
System.out.println("update count:"+result.getN());
db.requestDone();
}
/**
* pop array element(1,last;-1,first)
*/
public void popElementInArray(String _id){
coll = getCollection("ChildColl");
WriteResult result = coll.update(new BasicDBObject("_id", new ObjectId(_id)),new BasicDBObject("$pop",new BasicDBObject("arrays",-1)));//1,last;-1,first
System.out.println("update count:"+result.getN());
}
/**
* addToSet And Each array element
*/
public void addToSetAndEachElementInArray(String _id){
coll = getCollection("ChildColl");
List list = new ArrayList();
list.add("str0");
list.add("str1");
list.add(new BasicDBObject("arr99",99));
WriteResult result = coll.update(new BasicDBObject("_id", new ObjectId(_id)),new BasicDBObject("$addToSet",new BasicDBObject("arrays",new BasicDBObject("$each",list))));//1,last;-1,first
System.out.println("update count:"+result.getN());
}
/**
* 按数组位置更新文档(查询条件需要包含更新内容，$为数组位置占位符，只更新匹配到的第一个文档.)
*/
public void updatePositionInArray(String _id){
coll = getCollection("ChildColl");
WriteResult result = coll.update(new BasicDBObject("arrays.arr0", 100),new BasicDBObject("$set",new BasicDBObject("arrays.$.arr0",101)));
System.out.println("update count:"+result.getN());
}
以上都是一些基本的查询、更新操作，当然还有一些如map reduce和关联查询等复杂的方法，我将另写一篇blog总结一下。
参考文献包括：《mongodb权威指南》、《mongodb管理与开发精要》，另外文章开头提到的MongoDB官网内的develop zone也是很不错的资料来源。
PS：
mongodb driver在线API文档： http://api.mongodb.org/java/2.8.0/ （目前是2.8.0）