y);
while(cur.hasNext()) {
System.out.println(cur.next());
}
BasicDBObject query = new BasicDBObject();
query = new BasicDBObject();
query.put("i", new BasicDBObject("$gt", 20).append("$lte", 30)); // i.e. 20 < i <= 30
DBCursor cur = coll.find(query);
while(cur.hasNext()) {
System.out.println(cur.next());
}
注:查询指定条件的offer信息。
DBObject tmpdoc = col.findOne(doc);
DBObject tmpdoc = col.findOne(doc);注:查询单条记录;在很明确一条记录有且只有一条时,findOne()比较方便,免得游标移动麻烦。
5.更新:
DBObject tmpdoc = col.findOne(doc);
tmpdoc.put("i", (Integer)tmpdoc.get("i")+1);
System.out.println("update obj: " + col.findOne(tmpdoc));
DBObject tmpdoc = col.findOne(doc);
tmpdoc.put("i", (Integer)tmpdoc.get("i")+1);
System.out.println("update obj: " + col.findOne(tmpdoc));注:更新一条记录,先整个读出再更新部分信息再写入,切记不要读出一部分更新回去。
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6.插入:
int i=1000;
BasicDBObject doc = new BasicDBObject();
doc.put("i", i+1);
col.insert(doc);
System.out.println("insert obj: " + col.findOne(doc));
int i=1000;
BasicDBObject doc = new BasicDBObject();
doc.put("i", i+1);
col.insert(doc);
System.out.println("insert obj: " + col.findOne(doc));注:插入一条记录{i:1001},_id自动生成。
7.删除:
BasicDBObject doc = new BasicDBObject();
doc.put("i", i+1);
col.remove(doc);
System.out.println("insert obj: " + col.findOne(doc));
BasicDBObject doc = new BasicDBObject();
doc.put("i", i+1);
col.remove(doc);
System.out.println("insert obj: " + col.findOne(doc));注:删除一条记录。
摘自 madding.lip