Question

这一段代码的意思求解答

public String getRecordNumber(String queryString,
Hashtable<String, Object> map) throws DataAccessException {
List<Object> list = null;
String[] params = new String[map.size()];
Object[] value = new Object[map.size()];
Iterator<String> it = map.keySet().iterator();
int i = 0;
while (it.hasNext()) {
String key = it.next();
params[i] = key;
value[i++] = (Object) map.get(key);
}
list = getHibernateTemplate().findByNamedParam(queryString, params,
value);
String RecordNumber;
if (list != null && list.size() > 0) {
RecordNumber = (list.get(0)).toString();
} else {
RecordNumber = "0";
}
return RecordNumber;
}
while (it.hasNext()) {
String key = it.next();
params[i] = key;
value[i++] = (Object) map.get(key);
}
这一段该怎么理解

Answer 1

就是hibernate的一个多参数查询呗
findByNamedParam(queryString, params, value);
queryString 这是 查询语句 比如 from XXX where a=:aaa and b=:bbb
params 这是设置参数 参数1 参数2 ... 如 a, b
value 这是对应的值 参数1的值 参数2的值 ... 如 aaa , bbb

Answer 2

String[] params = new String[map.size()];
Object[] value = new Object[map.size()];
Iterator<String> it = map.keySet().iterator();
int i = 0;
while (it.hasNext()) {
String key = it.next();
params[i] = key;
value[i++] = (Object) map.get(key);
遍历hashmap,依次把key放入params,把value放入value数组

list = getHibernateTemplate().findByNamedParam(queryString, params,
value);
String RecordNumber;
if (list != null && list.size() > 0) {
RecordNumber = (list.get(0)).toString();
} else {
RecordNumber = "0";
}
return RecordNumber;
结果有数据就返回查询结果,没有就默认返回0

Answer 3

动态参数查询一条数据而已

Answer 4

用的是|,|,|,|,|,|

Answer 5

关于迭代器！