else语句失效
新手上路，请多关照。实现窗体填入个人信息，增加到数据库中。用了if else语句进行判断是否学号已存在，但弹出窗体填入信息点击确定按钮，第一次成功填入。不关闭窗体，保留原来的信息，再次点击按钮插入仍然是成功的 （应该是学号已经存在，插入信息失败）
求大神解答。{:10_266:}
代码如下：
package com.zsgc.jframe;
import java.awt.Color;
import java.awt.GridLayout;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JTextField;
import com.jdbc.driver.GetConn;
import com.jdbc.manager.*;
/**
*
* @author 23203 增加学生信息的窗体，待完善。
*
*/
public class InsertFrane extends JFrame { // ItemListener
// 下拉列表监听器
private JPanel panel1, panel2, panel3, panel4, panel5, panel6, panel7;
private JComboBox<String> comboBox1, comboBox2, comboBox3, comboBox4,
comboBox5;
private JButton button1, button2;
private JTextField textField1, textField2, textField3, textField4;
private String nation[] = { "汉", "白", "傣", "蒙古族", "水族", "维吾尔族", "美" };
private String sex[] = { "男", "女" };
private int START_YEAR = 1980;
private int END_YEAR = 2010;
public static void main(String[] args) {
InsertFrane A = new InsertFrane();
A.setVisible(true);
}
public InsertFrane() {
button1 = new JButton("确定");
button2 = new JButton("取消");
comboBox1 = new JComboBox<String>(nation);
comboBox2 = new JComboBox<String>(sex);
comboBox3 = new JComboBox<String>();
comboBox4 = new JComboBox<String>();
comboBox5 = new JComboBox<String>();
panel1 = new JPanel();
panel2 = new JPanel();
panel3 = new JPanel();
panel4 = new JPanel();
panel5 = new JPanel();
panel6 = new JPanel();
panel7 = new JPanel();
textField1 = new JTextField(10);
textField2 = new JTextField(10);
textField3 = new JTextField(10);
textField4 = new JTextField(10);
setTitle("增加学生信息");
setLocation(200, 200);
setSize(400, 400);
setResizable(false);
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setLayout(new GridLayout(8, 1));
panel1.add(new JLabel("学号："));
panel1.add(textField1);
panel2.add(new JLabel("姓名："));
panel2.add(textField2);
panel3.add(new JLabel("年级："));
panel3.add(textField3);
panel3.add(new JLabel("例如：1601,1602"));
panel4.add(new JLabel("专业："));
panel4.add(textField4);
panel5.add(new JLabel("民族："));
panel5.add(comboBox1);
panel5.add(new JLabel(" 性别："));
panel5.add(comboBox2);
panel6.add(new JLabel("生日：年："));
panel6.add(comboBox3);
panel6.add(new JLabel(" 月："));
panel6.add(comboBox4);
panel6.add(new JLabel(" 日："));
panel6.add(comboBox5);
panel7.add(button1);
panel7.add(button2);
add(panel1);
add(panel2);
add(panel3);
add(panel4);
add(panel5);
add(panel6);
add(panel7);
// 初始化年月日
for (int i = START_YEAR; i <= END_YEAR; i++) {
comboBox3.addItem("" + i);
}// 初始化年份
for (int i = 1; i <= 12; i++) {
comboBox4.addItem("" + i);
}// 初始化月份
for (int i = 1; i <= 31; i++) {
comboBox5.addItem("" + i);
}// 初始化号
comboBox4.addItemListener(new ItemListener() {
/**
* 下拉列表事件，解决闰年二月份问题。和别的事件处理方法一致，注意曾经写错（继承监听器，却没有注册监听器）
*/
@Override
public void itemStateChanged(ItemEvent e) {
int data = 31;
Object obj = comboBox4.getSelectedItem(); // getSelectedItem()方法，返回当前下拉列表的值（以对象的形式返回）
// 取得当前月份
if (obj != null)
comboBox5.removeAllItems();// removeAllItems()方法，删除掉下拉列表的所有的项目，清空掉日
int mouth = Integer.valueOf(obj.toString());// 将对象（月份）变为整数
if (mouth == 4 || mouth == 6 || mouth == 9 || mouth == 11) {
data = 30;
} else if (mouth == 2) {
int year = Integer.valueOf(comboBox3.getSelectedItem()
.toString());// 取得当前年号
if (year % 400 == 0 || (year % 4 == 0 && year % 100 != 0))// 是闰年
data = 29;
else
data = 28;
}
for (int i = 1; i <= data; i++) {
comboBox5.addItem("" + i);
}// 添加号
}
});
// 鼠标事件
button1.addMouseListener(new MouseAdapter() {
String sql = "select *from student_information";
@Override
public void mouseClicked(MouseEvent e) {
GetConn getconn = new GetConn();
Connection conn = getconn.getConnection();
try {
Statement statement1 = conn.createStatement();
ResultSet resultSet1 = statement1.executeQuery(sql);
while (resultSet1.next()) {
int userID = resultSet1.getInt("userId");
if (textField1.getText().equals("" + userID)) {
button1.setBackground(Color.RED);
JOptionPane.showMessageDialog(null, "此学号已存在");
break;
} else {
int UserId = Integer.parseInt(textField1.getText());
String Name = textField2.getText();
String Sex = String.valueOf(comboBox2
.getSelectedItem());
String birthday = String.valueOf(comboBox3
.getSelectedItem())
+ String.valueOf(comboBox4
.getSelectedItem())
+ String.valueOf(comboBox5
.getSelectedItem());
int Birthday = Integer.parseInt(birthday);
String Nation = String.valueOf(comboBox1
.getSelectedItem());
int Class1 = Integer.parseInt(textField3.getText());
String Zhuanye = textField4.getText();
new InsertInformation(UserId, Name, Sex, Birthday,
Nation, Class1, Zhuanye);// 调用插入的方法，连接数据库等等操作
button1.setBackground(Color.GREEN);
JOptionPane.showMessageDialog(null, "插入信息成功");
break;
}
}
} catch (SQLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} finally {
if (conn != null) {
try {
conn.close();// 关闭当前数据库连接
} catch (SQLException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
}
}
});
button2.addMouseListener(new MouseAdapter() {
@Override
public void mouseClicked(MouseEvent e) {
System.exit(0);
super.mouseClicked(e);
}
});
}
}
这里要用到刷新数据库的知识吗？还是程序本身的存在问题，{:10_266:}，不能沉，不能沉 本帖最后由 zlj19931010 于 2017-7-4 11:13 编辑
你单步调式下呗，没有你的数据库，我不能帮你调式 把报的错误信息发上来看下，应该是你分析的那样，表中有主键，主键不能重复，第二次添加的时候重复，如果是这样就会报SQLException，如果不是这个错误，那应该是逻辑错误 如果重复 肯定else肯定不能执行
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