这是我正在执行的代码。在这段代码中，我正在尝试使用我从组合框中获取的详细信息来更新数据库..
private void SubmitActionPerformed(java.awt.event.ActionEvent evt) {
Connection connection;
try {
int flag=1;
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (Exception ex) {
System.out.println("Error"+ex);
}
connection = DriverManager.getConnection("jdbc:derby://localhost:1527/loginDB", "login_user" ,"root");
String query = "INSERT into FACULTY_DETAILS (FACULTYNAME,LECTUREQUALITY,COMSKILLS,KNOWLEDGE,BEHAVIOUR,NOTESPROVIDED,PUNCTUALITY,SUGGESTION) values(?,?,?,?,?,?,?,?)";
PreparedStatement pt = connection.prepareStatement(query);
//Statement pt = connection.createStatement();
pt.executeUpdate();
ResultSet rs = pt.executeQuery("SELECT * FROM LOGIN_USER.FACULTY_DETAILS");
while(rs.next()){
if(rs.getString(1).equals(kapil.getText())){
pt.setString(2, (String) javalec.getSelectedItem());
pt.setString(3,(String)javacomm.getSelectedItem());
pt.setString(4,(String)javaknow.getSelectedItem());
pt.setString(5, (String) javabeh.getSelectedItem());
pt.setString(6, (String) javanot.getSelectedItem());
pt.setString(7, (String) javapun.getSelectedItem());
pt.setString(8,javatext.getText());
pt.executeUpdate(); flag=0;}
if(rs.getString(1).equals(ziaul.getText())){
pt.setString(2, (String) oslec.getSelectedItem());
pt.setString(3,(String)oscomm.getSelectedItem());
pt.setString(4,(String)osknow.getSelectedItem());
pt.setString(5, (String) osbeha.getSelectedItem());
pt.setString(6, (String) osnote.getSelectedItem());
pt.setString(7, (String) ospun.getSelectedItem());
pt.setString(8,ostext.getText());
pt.executeUpdate();
flag=0;}
if(rs.getString(1).equals(saurabh.getText())){
pt.setString(2, (String) daalec.getSelectedItem());
pt.setString(3,(String)daacomm.getSelectedItem());
pt.setString(4,(String)daakno.getSelectedItem());
pt.setString(5, (String) daabeh.getSelectedItem());
pt.setString(6, (String) daanot.getSelectedItem());
pt.setString(7, (String) daapun.getSelectedItem());
pt.setString(8,daatext.getText());
pt.executeUpdate();
flag=0;}
if(rs.getString(1).equals(gayatri.getText())){
pt.setString(2, (String) ecolec.getSelectedItem());
pt.setString(3,(String)ecocomm.getSelectedItem());
pt.setString(4,(String)ecokno.getSelectedItem());
pt.setString(5, (String) ecobeh.getSelectedItem());
pt.setString(6, (String) econot.getSelectedItem());
pt.setString(7, (String) ecopun.getSelectedItem());
pt.setString(8,ecotext.getText());
pt.executeUpdate();
flag=0;}
if(rs.getString(1).equals(tasleem.getText())){
pt.setString(2, (String) clec.getSelectedItem());
pt.setString(3,(String)ccomm.getSelectedItem());
pt.setString(4,(String)cknow.getSelectedItem());
pt.setString(5, (String) cbeh.getSelectedItem());
pt.setString(6, (String) cnote.getSelectedItem());
pt.setString(7, (String) cpun.getSelectedItem());
pt.setString(8,ctext.getText());
pt.executeUpdate();
flag=0;}
if(rs.getString(1).equals(saurabhs.getText())){
pt.setString(2, (String)graplec.getSelectedItem());
pt.setString(3,(String)grapcomm.getSelectedItem());
pt.setString(4,(String)grapknow.getSelectedItem());
pt.setString(5, (String) grapbeh.getSelectedItem());
pt.setString(6, (String) grapnot.getSelectedItem());
pt.setString(7, (String) grappun.getSelectedItem());
pt.setString(8,graphtext.getText());
pt.executeUpdate();
flag=0;}
if(rs.getString(1).equals(sanjay.getText())){
pt.setString(2, (String) softlec.getSelectedItem());
pt.setString(3,(String) softcomm.getSelectedItem());
pt.setString(4,(String) softknow.getSelectedItem());
pt.setString(5, (String) softbeh.getSelectedItem());
pt.setString(6, (String) softnot.getSelectedItem());
pt.setString(7, (String) softpun.getSelectedItem());
pt.setString(8,softtext.getText());
pt.executeUpdate();
flag=0;
}
if(flag==0){
JOptionPane.showMessageDialog(null,"Feedback Submitted Successfully");
}
}
} catch (SQLException ex) {
Logger.getLogger(Login.class.getName()).log(Level.SEVERE, null, ex);
}
}
这是我正在使用的代码请帮助我.. 我正在尝试执行我给出的代码，但它一直给我错误＆＃34;当前语句中至少有一个参数未初始化。＆＃34;所以请帮助......
答案 0 :(得分：1)
预准备语句中的SQL具有参数标记：
String query = "INSERT into FACULTY_DETAILS (FACULTYNAME,LECTUREQUALITY,COMSKILLS,KNOWLEDGE,BEHAVIOUR,NOTESPROVIDED,PUNCTUALITY,SUGGESTION) values(?,?,?,?,?,?,?,?)";
在执行SQL之前需要设置这些参数（如果没有值代替?，它就没有意义）。
但是，您尝试在不设置参数的情况下执行语句：
PreparedStatement pt = connection.prepareStatement(query);
pt.executeUpdate();
会导致您描述的错误。目前执行该声明并不清楚你打算做什么。
此外，您尝试对查询和更新使用相同的语句对象。我不相信这会奏效。为查询创建单独的语句：
PreparedStatement queryStatement = connection.prepareStatement("SELECT * FROM LOGIN_USER.FACULTY_DETAILS");
ResultSet rs = queryStatement.executeQuery();
最后，请注意，pt.executeUpdate()块中if的后续调用也会在未设置所有参数的情况下发生，因为在任何这些情况下都不会设置参数编号1。您还需要将该参数设置为适当的值。
答案 1 :(得分：1)
这里的问题是，在设置了您需要的详细信息之后，您正在准备一份将在以后使用的声明。
然后，您尝试执行executeUpdate()，期望设置值。
解决方案：在获取executeUpdate()之前移除ResultSet并设置PreparedStatement的值。
private void SubmitActionPerformed(java.awt.event.ActionEvent evt) {
Connection connection;
PreparedStatement pt;
Statement st;
ResultSet rs;
try {
int flag = 1;
try {
Class.forName("com.mysql.jdbc.Driver");
} catch (Exception ex) {
System.out.println("Error" + ex);
}
connection = DriverManager.getConnection("jdbc:derby://localhost:1527/loginDB", "login_user", "root");
String query = "INSERT into FACULTY_DETAILS (FACULTYNAME,LECTUREQUALITY,COMSKILLS,KNOWLEDGE,BEHAVIOUR,NOTESPROVIDED,PUNCTUALITY,SUGGESTION) values(?,?,?,?,?,?,?,?)";
pt = connection.prepareStatement(query);
st = connection.createStatement();
rs = st.executeQuery("SELECT * FROM LOGIN_USER.FACULTY_DETAILS");
while (rs.next()) {
if (rs.getString(1).equals(kapil.getText())) {
pt.setString(2, (String) javalec.getSelectedItem());
pt.setString(3, (String) javacomm.getSelectedItem());
pt.setString(4, (String) javaknow.getSelectedItem());
pt.setString(5, (String) javabeh.getSelectedItem());
pt.setString(6, (String) javanot.getSelectedItem());
pt.setString(7, (String) javapun.getSelectedItem());
pt.setString(8, javatext.getText());
pt.executeUpdate();
flag = 0;
} else if (rs.getString(1).equals(ziaul.getText())) {
pt.setString(2, (String) oslec.getSelectedItem());
pt.setString(3, (String) oscomm.getSelectedItem());
pt.setString(4, (String) osknow.getSelectedItem());
pt.setString(5, (String) osbeha.getSelectedItem());
pt.setString(6, (String) osnote.getSelectedItem());
pt.setString(7, (String) ospun.getSelectedItem());
pt.setString(8, ostext.getText());
pt.executeUpdate();
flag = 0;
} else if (rs.getString(1).equals(saurabh.getText())) {
pt.setString(2, (String) daalec.getSelectedItem());
pt.setString(3, (String) daacomm.getSelectedItem());
pt.setString(4, (String) daakno.getSelectedItem());
pt.setString(5, (String) daabeh.getSelectedItem());
pt.setString(6, (String) daanot.getSelectedItem());
pt.setString(7, (String) daapun.getSelectedItem());
pt.setString(8, daatext.getText());
pt.executeUpdate();
flag = 0;
} else if (rs.getString(1).equals(gayatri.getText())) {
pt.setString(2, (String) ecolec.getSelectedItem());
pt.setString(3, (String) ecocomm.getSelectedItem());
pt.setString(4, (String) ecokno.getSelectedItem());
pt.setString(5, (String) ecobeh.getSelectedItem());
pt.setString(6, (String) econot.getSelectedItem());
pt.setString(7, (String) ecopun.getSelectedItem());
pt.setString(8, ecotext.getText());
pt.executeUpdate();
flag = 0;
} else if (rs.getString(1).equals(tasleem.getText())) {
pt.setString(2, (String) clec.getSelectedItem());
pt.setString(3, (String) ccomm.getSelectedItem());
pt.setString(4, (String) cknow.getSelectedItem());
pt.setString(5, (String) cbeh.getSelectedItem());
pt.setString(6, (String) cnote.getSelectedItem());
pt.setString(7, (String) cpun.getSelectedItem());
pt.setString(8, ctext.getText());
pt.executeUpdate();
flag = 0;
} else if (rs.getString(1).equals(saurabhs.getText())) {
pt.setString(2, (String) graplec.getSelectedItem());
pt.setString(3, (String) grapcomm.getSelectedItem());
pt.setString(4, (String) grapknow.getSelectedItem());
pt.setString(5, (String) grapbeh.getSelectedItem());
pt.setString(6, (String) grapnot.getSelectedItem());
pt.setString(7, (String) grappun.getSelectedItem());
pt.setString(8, graphtext.getText());
pt.executeUpdate();
flag = 0;
} else if (rs.getString(1).equals(sanjay.getText())) {
pt.setString(2, (String) softlec.getSelectedItem());
pt.setString(3, (String) softcomm.getSelectedItem());
pt.setString(4, (String) softknow.getSelectedItem());
pt.setString(5, (String) softbeh.getSelectedItem());
pt.setString(6, (String) softnot.getSelectedItem());
pt.setString(7, (String) softpun.getSelectedItem());
pt.setString(8, softtext.getText());
pt.executeUpdate();
flag = 0;
}
if (flag == 0) {
JOptionPane.showMessageDialog(null, "Feedback Submitted Successfully");
}
}
} catch (SQLException ex) {
Logger.getLogger(Login.class.getName()).log(Level.SEVERE, null, ex);
} finally {
if (rs != null) {
rs.close();
}
if (st != null) {
st.close();
}
if (pt != null) {
pt.close();
}
if (connection != null) {
connection.close();
}
}
}
注意：我在else if的位置使用if以避免重复的条件检查。并且，最后阻止以避免内存泄漏