在传入三个参数后，用于模糊查的sql语句查询不出值，也，不报错

Question

public List findBook(int pageIndex,int pageSize,String key) {
List list=new ArrayList();
try {
String sql;
List tiaojian=new ArrayList();
if(key==null||key.length()==0||key.equals("null")){
sql="select * from book limit ?,?"; }else{
sql="select * from book where bookname like ? limit ?,?";
tiaojian.add("'"+key+"%'"); } tiaojian.add((pageIndex-1)*pageSize); tiaojian.add(pageSize);
rs=query(sql,tiaojian);
for (int i = 0; i < tiaojian.size(); i++) {
System.out.println(tiaojian.get(i)); }
while(rs.next()){
Book b=new Book();
b.setBookid(rs.getInt("bookid")); b.setBookname(rs.getString("bookName")); b.setCount(rs.getInt("count")); b.setImage(rs.getString("image")); b.setPrice(rs.getDouble("price")); list.add(b);
} } catch (SQLException e) { e.printStackTrace();
}finally{
closeAll();
} return list; }

Answer 1

你这是模糊查询吗，不应该是“%”+key+“”吗，如果你的key什么都没有就是都差不出来，key也不能为""这个