java - 创建一个 Student 将其传递给 SQL 对象并在线程 "AWT-EventQueue-0"lang.ArrayIndexOutOfBoundsException : 4 中获取异常

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这个问题已经有答案了:

What causes a java.lang.ArrayIndexOutOfBoundsException and how do I prevent it? (25 个回答)

已关闭 5 年前。

大家好，我的 Java 代码遇到了问题。我是 Java 的新手，而且我喜欢 Java。截至目前，我正在使用 netbeans 在 java 中开发桌面应用程序，但遇到了运行时错误。谁能帮我解决这个代码。问题似乎是什么。

Exception in thread "AWT-EventQueue-0" lang.ArrayIndexOutOfBoundsException: 4

            Student student = new Student();
            student.setFirstName("JOHN");
            student.setlastName("DOE");
            student.setAge(31);
            student.setGender("Male");
            student.setEmailAddress("xyz@xc.com");
            student.setStduent_Id(314);
            student.setLevel("Grade 5");

等等。假设学生对象具有正确的值，我已经使用完整的条目测试了学生对象，但仍然遇到问题。我的怀疑是在 PreParedStatement 中，任何人都可以指出我的代码所具有的确切信息。 Tnx 和问候

            fname = student.getFirst_name();
            student.getLast_name();
            age = student.getAge();
            student.getGender();
            email_address = student.getEmail_add();
            student_id= student.getStudent_id();
            level=  student.getLevel();
            room = student.getRoom();
            date_birth = student.getDate_birth();
            home_phone_number = student.getHome_phone();
            mobile_number = student.getMobile_phone();
            street = student.getStreet();
            city = student.getCity();
            state_province = student.getState_province();
            zip_postal_codes = student.getZip_postal();
            notes = student.getNotes();


            String SQL = "UPDATE tbl_students SET first_name ='?', last_name = '?', age = 22, gender = '?', email_address='?',student_id = ?, level = '?', room = '?', date_of_birth='?', home_phone_number= ?, mobile_number = ?, street='?', city='?', state_province ='?', zip_postal_code=?, notes = '?' where student_id =" + student_id;



            String fname = student.getFirst_name();
            String  lname = student.getLast_name();
            int age = student.getAge();
            String  gender = student.getGender();
            String email_address = student.getEmail_add();
            int student_id= student.getStudent_id();
            String level=  student.getLevel();
            String room = student.getRoom();

            String date_birth = student.getDate_birth();
            int home_phone_number = student.getHome_phone();

            int mobile_number = student.getMobile_phone();
            String street = student.getStreet();
            String city = student.getCity();
            String state_province = student.getState_province();
            int zip_postal_codes = student.getZip_postal();
            String notes = student.getNotes();

            DBMS.CreateConn();

            Connection conn;
            conn =DBMS.CreateConn();

            PreparedStatement pst = conn.prepareStatement(SQL);

            pst.setString(1, fname);
            pst.setString(2, lname);
            pst.setInt(3, age);
            pst.setString(4, gender);
            pst.setString(5, email_address);
            pst.setInt(6, student_id);
            pst.setString(7,level);
            pst.setString(8, room);
            pst.setString(9, date_birth);
            pst.setInt(10, home_phone_number);
            pst.setInt(11, mobile_number);
            pst.setString(12, street);
            pst.setString(13, city);
            pst.setString(14, state_province);
            pst.setInt(15, zip_postal_codes);
            pst.setString(16, notes);


            int result = pst.executeUpdate();

Answer 1

您必须删除查询中?周围的所有'，否则它们不会被算作参数，而是问号的实际字符串。

String SQL = "UPDATE tbl_students SET first_name =?, last_name = ?, age = 22, gender = ?, email_address=?,student_id = ?, level = ?, room = ?, date_of_birth=?, home_phone_number= ?, mobile_number = ?, street=?, city=?, state_province =?, zip_postal_code=?, notes = ? where student_id =" + student_id;

发生错误的原因是您当前正好有 4 个未加引号的问号，这意味着四个参数，这意味着对设置参数 0 到 3 的调用成功，但在索引 4 处设置参数超出范围。

顺便说一句，为什么您不为 where 条件值使用参数？