無法向Prepared Statement添加參數。 JAVA。 Spring MVC

Question

我有一個Prepared Statements的方法。當我使用set string/int/etc方法添加參數時，它會顯示我java.sql.SQLException: Parameter index out of range (3 > number of parameters, which is 0). 並且在控制檯中，我收到了這樣的查詢select*from users where users.enabled = true AND users.weight <= ? AND users.gender LIKE ?。它不會取代我的?元素。 這是我的方法！請幫助！

 @SuppressWarnings("unchecked") 
    @Override 
    public List<Users> listUsersSort(int weight, String gender, String place, int ageTo, String currentUser) { 
     System.out.println(weight+gender+place+ageTo+currentUser); 
     Connection dbConnection = null; 
     PreparedStatement preparedStatement = null; 
     Session session=null; 

     int iterator=0; 
     List<Users> usersList =null; 
     String selectSQL="select users.username, users.checkusr, users.password, users.name, users.enabled, users.surname, users.email, users.gender, users.age, users.weight, users.height, users.sport, users.place, users.photo from users where users.enabled = true"; 
     System.out.println(selectSQL); 
     Connection con=getConnection(); 
     try { 
      preparedStatement = con.prepareStatement(selectSQL); 
     } catch (SQLException e1) { 
      // TODO Auto-generated catch block 
      e1.printStackTrace(); 
     } 
     //String query = "; 
     if (weight<40 == false) { 
      String weightParam = " AND users.weight <= ?"; 
      selectSQL=selectSQL.concat(weightParam); 
      System.out.println(selectSQL); 
     // query = query.concat(weightParam); 
      try { 
       iterator+=1; 
       System.out.println(iterator); 
       preparedStatement.setInt(iterator, weight); 
      } catch (SQLException e) { 
       System.out.println("second catch block"); 
       e.printStackTrace(); 
      } 
      System.out.println(selectSQL); 
     } 
     if (gender.isEmpty() == false) { 
      String genderParam = " AND users.gender LIKE '?'"; 
      selectSQL=selectSQL.concat(genderParam); 
      try { 
       iterator+=1; 
       preparedStatement.setString(iterator, gender); 
      } catch (SQLException e) { 
       // TODO Auto-generated catch block 
       e.printStackTrace(); 
      } 

      //String genderParam = " AND users.gender LIKE " + "'" + gender + "'"; 
      //query = query.concat(genderParam); 
      System.out.println(selectSQL); 
     } 

     if (place.isEmpty() == false) { 
      String placeParam = " AND users.place LIKE '?'"; 
      selectSQL=selectSQL.concat(placeParam); 
      try { 
       iterator+=1; 
       preparedStatement.setString(iterator, place); 
      } catch (SQLException e) { 
       // TODO Auto-generated catch block 
       e.printStackTrace(); 
      } 
      //query = query.concat(placeParam); 
      System.out.println(selectSQL); 
     } 
     if (ageTo<40 == false) { 
      String age = " AND users.age <= ?"; 
      selectSQL=selectSQL.concat(age); 
      try { 
       iterator+=1; 
       preparedStatement.setInt(iterator, ageTo); 
      } catch (SQLException e) { 
       // TODO Auto-generated catch block 
       e.printStackTrace(); 
      } 
      //query = query.concat(age); 
      System.out.println(selectSQL); 
     } 
     String withoutUser=" AND users.username NOT LIKE '?'"; 
     //query=query.concat(withoutUser); 
     selectSQL=selectSQL.concat(withoutUser); 
     try { 
      iterator+=1; 
      preparedStatement.setString(iterator, currentUser); 
     } catch (SQLException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 
     ResultSet rs=null; 
     try { 
      rs = preparedStatement.executeQuery(); 
     } catch (SQLException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 
     try { 
      while (rs.next()) { 

       String username = rs.getString("username"); 

       System.out.println("username : " + username); 

      } 
     } catch (SQLException e) { 
      // TODO Auto-generated catch block 
      e.printStackTrace(); 
     } 

     return usersList; 
    } 

Answer 1

你正在做preparedStatement = con.prepareStatement(selectSQL);你是通過連接weightParam等修改您的selectSQL前

您連接weightParam等後selectSQL您應該執行準備預處理語句的以下任務：

try { 
    preparedStatement = con.prepareStatement(selectSQL); 
} catch (SQLException e1) { 
    e1.printStackTrace(); 
} 

然後嘗試通過執行以下操作將值設置爲您的預備聲明：

preparedStatement.setInt(iterator, weight); 

或者，你可以做這樣的事情：

if (weight<40 == false) { 
    String weightParam = " AND users.weight <= ?"; 
    selectSQL = selectSQL.concat(weightParam); 
    System.out.println(selectSQL); 

    try { 
     ++iterator; 
     System.out.println(iterator); 
     /* Note : Change Here */ 
     preparedStatement = con.prepareStatement(selectSQL); 
     preparedStatement.setInt(iterator, weight); 
    } catch (SQLException e) { 
     System.out.println("second catch block"); 
     e.printStackTrace(); 
    } 
    System.out.println(selectSQL); 
}