mongodb字段值自增长实现代码

{
  "_id":1,
  "title": "标题",
  "content": "内容1",
  "type": "类型"
}

db.createCollection("counters")

db.counters.insert({_id:"objId",sequence_value:0})

db.counters.findAndModify({
  query: {_id: "objId" },
  update: {$inc:{sequence_value:1}},
  new: true
}).sequence_value;

db.collection.findAndModify({
  query: <document>, //定义关于哪些记录需要修改的选择标准
  sort: <document>, //确定选择标准检索多个文档时应修改的文档
  new: <boolean>, //表示将显示修改后的文档
  fields: <document>, //指定要返回的字段集
  upsert: <boolean> //如果选择标准无法检索文档，则创建一个新文档
  remove: <boolean> //为true，query指定的文档将从数据库中删除
)}

db.createCollection("sms")

db.sms.insert({
  _id: db.counters.findAndModify({query:{_id: "objId" },update: {$inc:{sequence_value:1}},"new":true}).sequence_value,
  title: "标题1",
  content: "短信1",
  type: "1"
})

db.sms.find({}).sort({_id:1})

private MongoDatabase conn;
 
static{
  this.conn = getDatabase(databaseName);
}
 
/**
 * 连接数据库
 * @param databaseName 数据库名称
 * @return       数据库连接对象
 */
private static MongoDatabase getDatabase(databaseName){
  MongoDatabase mongoDatabase = null;
  try{  
    // 连接到 mongodb 服务
    MongoClient mongoClient = new MongoClient( "localhost" , 27017 );
  
    // 连接到数据库
    MongoDatabase mongoDatabase = mongoClient.getDatabase(databaseName); 
    System.out.println("Connect to database successfully");
    
  }catch(Exception e){
    System.err.println( e.getClass().getName() + ": " + e.getMessage() );
  }
  return mongoDatabase;
}
 
/**
 * 获取最新序列号
 * @return 序列号
 */
private static int getNextSequenceValue(){
  DBCollection collection = conn.getCollection("counters");
  DBObject query = new BasicDBObject("_id", new BasicDBObject("$eq", "objId"));
  DBObject newDocument =new BasicDBObject();
  newDocument.put("$inc", new BasicDBObject().append("sequence_value", 1));
  newDocument.put("new": true);
  DBObject ret = collection.findAndModify(query, newDocument);
  if (ret == null){
    return 0;
  }else{
    return (Integer)ret.get("sequence_value");
  }
}
 
/**
 * 新增集合文档
 */
public static void addSms(){
  int id = getNextSequenceValue();
  if(id != 0){
    DBCollection collection = conn.getCollection("sms");
    List<Document> documents = new ArrayList<Document>();
    for(int i = 0; i < 20; i++){
      int id = getNextSequenceValue();
      Document document = new Document("_id", id).
      append("title", "标题" + i).
      append("content", "短信" + i). 
      append("type", 1);
      documents.add(document);
    }
    collection.insertMany(documents); 
    System.out.println("文档插入成功"); 
 
  }
}
 
/**
 * 查询集合
 */
public static void findSms(){
  DBCollection collection = conn.getCollection("sms");
  FindIterable<Document> findIterable = collection.find(); 
  MongoCursor<Document> mongoCursor = findIterable.iterator(); 
  while(mongoCursor.hasNext()){ 
    System.out.println(mongoCursor.next()); 
  }
}