java - 错误 : SQLException: Parameter index out of range (1 > number of parameters, 为 0)

Question

这个问题已经有答案了:

java.sql.SQLException Parameter index out of range (1 > number of parameters, which is 0) [closed] (2 个回答)

已关闭 4 年前。

尽管上述准备好的语句的语法是正确的，但我收到以下错误:

java.sql.SQLException: Parameter index out of range (1 > number of parameters, which is 0)

预期结果是以下代码必须返回表的值

try{
        conn = DatabaseMain.getConnection();
        String instqury = "Select quality_name,quality_size,quality_weight,quality_spec from quality where quality_code = '?'";
        pst1 = conn.prepareStatement(instqury);
        pst1.setString(1, quality);

        rs1 = pst1.executeQuery();
        rs1.next();
        name.setText(String.valueOf(rs1.getString("quality_name")));

    }
    catch(Exception e){
        e.printStackTrace();
        System.out.println("Error in setting labels for Machine View");
    }

Answer 1

不要将占位符放在单引号之间:

String instqury = 
    "Select quality_name,quality_size,quality_weight,quality_spec " + 
    "from quality where quality_code = ?";
                                       ^-- here