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);
        }
    }