java学习(三) java 中 mongodb的各种操作
一. 常用查询:
1. 查询一条数据:(多用于保存时判断db中是否已有当前数据,这里 is 精确匹配,模糊匹配 使用 regex...)
public PageUrl getByUrl(String url) { return findOne(new Query(Criteria.where("url").is(url)),PageUrl.class); }
2. 查询多条数据:linkUrl.id 属于分级查询
public List<PageUrl> getPageUrlsByUrl(int begin, int end,String linkUrlid) { Query query = new Query(); query.addCriteria(Criteria.where("linkUrl.id").is(linkUrlid)); return find(query.limit(end - begin).skip(begin), PageUrl.class); }
3. 模糊查询:
public long getProcessLandLogsCount(List<Condition> conditions) { Query query = new Query(); if (conditions != null && conditions.size() > 0) { for (Condition condition : conditions) { query.addCriteria(Criteria.where(condition.getKey()).regex(".*?\\" +condition.getValue().toString()+ ".*"));
} } return count(query, ProcessLandLog.class); }
4. gte: 大于等于,lte小于等于...注意查询的时候各个字段的类型要和mongodb中数据类型一致
public List<ProcessLandLog> getProcessLandLogs(int begin,int end,List<Condition> conditions,String orderField,Direction direction) { Query query = new Query(); if (conditions != null && conditions.size() > 0) { for (Condition condition : conditions) { if(condition.getKey().equals("time")){ query.addCriteria(Criteria.where("time").gte(condition.getValue())); //gte: 大于等于 }else if(condition.getKey().equals("insertTime")){ query.addCriteria(Criteria.where("insertTime").gte(condition.getValue())); }else{ query.addCriteria(Criteria.where(condition.getKey()).is(condition.getValue())); } } } return find(query.limit(end - begin).skip(begin).with(new Sort(new Sort.Order(direction, orderField))), ProcessLandLog.class); }
public List<DpsLand> getDpsLandsByTime(int begin, int end, Date beginDate,Date endDate) {
return find(new Query(Criteria.where("updateTime").gte(beginDate).lte(endDate)).limit(end - begin).skip(begin),
DpsLand.class);
}
查询字段不存在的数据
public List<GoodsDetail> getGoodsDetails2(int begin, int end) { Query query = new Query(); query.addCriteria(Criteria.where("goodsSummary").not()); return find(query.limit(end - begin).skip(begin),GoodsDetail.class); }
5. 查询数量:
public long getPageInfosCount(List<Condition> conditions) { Query query = new Query(); if (conditions != null && conditions.size() > 0) { for (Condition condition : conditions) {
query.addCriteria(Criteria.where(condition.getKey()).is(condition.getValue())); } } return count(query, PageInfo.class); }
6. 更新一条数据的一个字段:
public WriteResult updateTime(PageUrl pageUrl) { String id = pageUrl.getId(); return updateFirst(new Query(Criteria.where("id").is(id)),Update.update("updateTime", pageUrl.getUpdateTime()), PageUrl.class); }
7. 更新一条数据的多个字段:
//调用更新 private void updateProcessLandLog(ProcessLandLog processLandLog, int crawlResult) { List<String> fields = new ArrayList<String>(); List<Object> values = new ArrayList<Object>(); fields.add("state"); fields.add("result"); fields.add("time"); values.add("1"); values.add(crawlResult); values.add(Calendar.getInstance().getTime()); processLandLogReposity.updateProcessLandLog(processLandLog, fields, values); } //更新 public void updateProcessLandLog(ProcessLandLog land, List<String> fields,List<Object> values) { Update update = new Update(); int size = fields.size(); for(int i = 0 ; i < size; i++){ String field = fields.get(i); Object value = values.get(i); update.set(field, value); } updateFirst(new Query(Criteria.where("id").is(land.getId())), update,ProcessLandLog.class); }
8. 删除数据:
public void deleteObject(Class<T> clazz,String id) { remove(new Query(Criteria.where("id").is(id)),clazz); }
9.保存数据:
//插入一条数据
public void saveObject(Object obj) { insert(obj); }
//插入多条数据 public void saveObjects(List<T> objects) { for(T t:objects){ insert(t); } }