Question

我在Java中运行一组SQL查询来检索a，b和c值。之后我想用它们做一些操作并将结果打印给用户。

运行以下代码时，我收到“java.lang.NumberFormatException：For input string”：

try {
    String sql1="SELECT COUNT(CASE WHEN Type = 'Sick' THEN 1 ELSE 0 END) AS sick FROM `leave` WHERE `leave`.`EID`=? AND `leave`.`Month`=?";
    pst=conn.prepareStatement(sql1);
    int a = Integer.parseInt(sql1); 
    String sql2="SELECT COUNT(CASE WHEN Type = 'annual' THEN 1 ELSE 0 END) AS annual FROM `leave` WHERE `leave`.`EID`=? AND `leave`.`Date`=?";
    pst=conn.prepareStatement(sql2);
    int b= Integer.parseInt(sql2);
    String sql3="SELECT COUNT(CASE WHEN Type = 'Half day' THEN 1 ELSE 0 END) AS Half_day FROM `leave` WHERE `leave.EID`=? AND `leave`.`Date`=?";
    pst=conn.prepareStatement(sql3);
    rs=pst.executeQuery();
    int c= Integer.parseInt(sql3);

    if ((a+b+(c/2)) < 14) {
        int double_pay = 14 - (a+b+(c/2));
    }
    else {
        int double_pay = 0;
    }
    txt_double_pay.setText(double_pay+"");
} 
catch(Exception e){
    JOptionPane.showMessageDialog(null,e);
}

有谁知道这个例外的原因？

Answer 1

原因是

Integer.parseInt(sql3)

要求 sql3 是一个包含数据的字符串，可以将其解析为整数..

你的sql3对象正在改为：

sql3="SELECT COUNT(CASE WHEN Type = 'Half day' THEN 1 ELSE 0 END) 
   AS Half_day FROM `leave` WHERE `leave.EID`=? AND `leave`.`Date`=?";

所以java永远不会得到任何数量的字符串....

“java.lang.NumberFormatException：对于输入字符串”这个异常的原因是什么

1 个答案: