//按照參數集合進行查詢
public?List<Goddess>?queryByParams(List<Map<String,Object>>?params)?throws?Exception{
????List<Goddess>?goddesses?=?new?ArrayList<Goddess>();
????Connection?conn?=?DBHelper.getConn();
????StringBuilder?sb?=?new?StringBuilder();
????sb.append("select?*?from?imooc_goddess?where?1=1?");
????if?(params!=null&&params.size()>0){
????????for?(int?i=0;i<params.size();i++)?{
????????????if(i?==?0){
????????????????Map<String,?Object>?param?=?params.get(i);
????????????????sb.append("?and?"+"?(?"?+?param.get("name")?+?"?"?+?param.get("relat")?+?"?"?+?param.get("value")?+?"?");
????????????}else?if(i==1){
????????????????Map<String,?Object>?param?=?params.get(i);
????????????????sb.append("?or?"?+?param.get("name")?+?"?"?+?param.get("relat")?+?"?"?+?param.get("value")?+?"?");
????????????}
????????}
????????sb.append("?)?");
????}
????PreparedStatement?statement?=?conn.prepareStatement(sb.toString());
????System.out.println(sb.toString());
????ResultSet?rs?=?statement.executeQuery();
????Goddess?g?=?null;
????while(rs.next()){
????????g=new?Goddess();
????????g.setUser_name(rs.getString("user_name"));
????????g.setId(rs.getInt("id"));
????????g.setAge(rs.getInt("age"));
????????g.setSex(rs.getInt("sex"));
????????g.setBirthday(rs.getDate("birthday"));
????????g.setEmail(rs.getString("email"));
????????g.setMobile(rs.getString("mobile"));
????????g.setCreate_date(rs.getDate("create_date"));
????????g.setCreate_user(rs.getString("create_user"));
????????g.setUpdate_date(rs.getDate("update_date"));
????????g.setUpdate_user(rs.getString("update_user"));
????????g.setIsdel(rs.getInt("isdel"));
????????goddesses.add(g);
????}
????return?goddesses;
}

main方法：
GoddessDao?gd?=new?GoddessDao();
List<Map<String,Object>>?params?=?new?ArrayList<Map<String,Object>>();
Map<String,Object>?param1?=?new?HashMap<String,?Object>();
param1.put("name","user_name");
param1.put("relat","=");
param1.put("value","'小美'");
params.add(param1);
Map<String,Object>?param2?=?new?HashMap<String,?Object>();
param2.put("name","mobile");
param2.put("relat","=");
param2.put("value","'187'");
params.add(param2);
List<Goddess>?goddesses?=?gd.queryByParam(params);
for?(Goddess?g?:?goddesses){
????System.out.println(g.toString());
}


是?i==0?判斷不了嗎？