关于search 查询女神信息代码 问题

else if(OPERATION_SEARCH.equals(in.toUpperCase())

||OPERATION_SEARCH.substring(0,1).equals(in.toUpperCase())

||OPERATION_SEARCH.equals(previous)){

previous =OPERATION_SEARCH;

//查找

List<Map<String,Object>> params=new ArrayList<Map<String,Object>> ();

Map<String,Object> param=new HashMap<String,Object>();

if(step==1){

System.out.println("请输入的name：");

}else if(2==step){

param.put("name", in);

System.out.println("请输入的关系：");

}else if(3==step){

param.put("rela", in);

System.out.println("请输入的结果：");

}else if(4==step){

param.put("value", in);

params.add(param);

try {

List<Goddess> gs =action.query(params);

for(Goddess g:gs){

System.out.print(g.toString());

}

} catch (Exception e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

}

if(OPERATION_SEARCH.equals(previous)){

step++;

}

}

最后显示结果

select * from imooc_goddess where 1=1 and null null 3

com.mysql.jdbc.exceptions.MySQLSyntaxErrorException: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'null 3' at line 1

不知道最后sql为什么是null，不是传了值吗