/**
* 插入vo的所有字段.如果vo的id有值并且值大于0,则使用此值插入,否则生成一个id插入.
* 此方法不依赖于数据库id的自增,使用max(id)+1的方式生成id.所以此方法会开启一个事务.如果失败,会放弃添加并回滚.
*
* @param t vo
*/
public void insert(T t) throws Exception {
String sql = this.generator.insert(t.getClass());
Connection con = tran.getConnection(jndiName);
int id = this.getId(t);
if (id <= 0) {
String next = this.generator.nextId(t.getClass());
ResultSet rs = con.createStatement().executeQuery(next);
if (rs.next()) {
Object o = rs.getObject(1);
if (o == null) { // 可能还没有记录
id = 1;
} else {
id = Integer.valueOf(String.valueOf(o));
}
}
}
if (id <= 0) {
return;
}
PreparedStatement ps = con.prepareStatement(sql);
Field[] fields = listFieldsWithoutId(t.getClass());
int index = 1;
ps.setInt(index++, id);
for (Field f : fields) {
this.setParamter(ps, index++, t, f);
}
ps.executeUpdate();
}
/**
* 更新vo,使用vo的id作为条件,更新vo的所有字段.<br>
* 慎用此方法,有可能更新到你不愿意更新的字段
*
* @param t vo
*/
public void update(T t) throws Exception {
String sql = this.generator.update(t.getClass());
Connection con = tran.getConnection(jndiName);
PreparedStatement ps = con.prepareStatement(sql);
int index = 1;
Field[] fields = listFieldsWithoutId(t.getClass());
for (Field f : fields) {
this.setParamter(ps, index++, t, f);
}
ps.setInt(index, this.getId(t));
ps.executeUpdate();
}
/**
* 获取一个vo
*
* @param id vo的id
* @return vo或者null
*/
public T fetch(Object id) throws Exception {
Class<T> type = this.getPoType();
String sql = this.generator.fetch(type);
Connection con = tran.getConnection(jndiName);
PreparedStatement ps = con.prepareStatement(sql);
ps.setObject(1, id);
ResultSet rs = ps.executeQuery();
if (rs.next()) {
T t = type.cast(type.newInstance());
this.fillVO(rs, t);
return t;
}
return null;
}
/**
* 删除一个vo
*
* @param o vo或者id
*/
public void delete(Object o) throws Exception {
if (o == null) {
return;
}
Connection con = tran.getConnection(jndiName);
int id = this.getVOId(o);
if (id > 0) {
String sql = this.generator.delete(this.getPoType());
PreparedStatement ps = con.prepareStatement(sql);
ps.setObject(1, id);
ps.executeUpdate();
} else {
new RuntimeException("传入的参数:" + o + ",无法正确得到id!");
}
}
/**
* 查询所有的vo,没有考虑分页
*
* @return vo的list,没有任何可用值返回emptylist
*/
public List<T> query(Cnd cnd) throws Exception {
Class<T> type = this.getPoType();
String sql = this.generator.query(type);
if (cnd != null) {
sql += cnd.toString();
}
Connection con = tran.getConnection(jndiName);
PreparedStatement ps = con.prepareStatement(sql);
ResultSet rs = ps.executeQuery();
ArrayList<T> list = new ArrayList<T>();
while (rs.next()) {
T t = type.cast(type.newInstance());
this.fillVO(rs, t);
list.add(t);
}
return list;
}