Explanation:
1. This article is the function realization of Java form (load data, delete a row of data, add order)
2. Need to use two other classes DB. Article http://t.csdn.cn/7m4pk)
3. For the design requirements of the database, see the test questions for details
Main interface:
Function 1: As soon as the program is executed, the table loads data
The specific implementation steps are as follows:
1. In the top constructor of the main form code, add and write the following code (the code in the red box)
2. A method to customize and initialize table data: (write below the constructor, as shown above:)
The source code is as follows:
//自定义的方法：用于初始化表格数据
private void initTable(String sql) {
// 1.准备好所有的数据，放入 data 中
Vector data = new Vector();
ResultSet rs = BaseDao.cx(sql); // 查询数据库
try {
while (rs.next()) {
Vector line = new Vector(); // line 代表存放一行数据的集合
int id = rs.getInt(1); //分别从数据库中取出对应的值
String name = rs.getString(2);
double num = rs.getDouble(3);
String oid = rs.getString(4);
String desc = rs.getString(5);
line.add(id); //将上面获取到的每个数据放到行集合中
line.add(name);
line.add(num);
line.add(oid);
line.add(desc);
data.add(line); // 将当前行存入大的data中
}
} catch (SQLException e) {
e.printStackTrace();
}
// 2.准备好标题文字，放入 bt 中
Vector bt = new Vector(); // bt 用于存放标题
bt.add("编号");
bt.add("商品名字");
bt.add("商品价格");
bt.add("订单编号");
bt.add("订单描述");
// 3.最终任务就是用上面准备好的 数据 和 标题 填充 表格
jTable1.setModel(new DefaultTableModel(data, bt));
}
Function 2: The function of the delete button
Implementation steps
1. Double-click the delete button in the main form, and it will automatically go to the code for writing the button event:
2. Write the delete function in the body of the above automatically opened code method, the code is as follows:
The source code is as follows :
private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {
int rowCount = jTable1.getSelectedRowCount(); // 获取选中的行数，如果为0，则说明没有选中任何行
if (rowCount == 0) {
JOptionPane.showMessageDialog(null, "您未选择任何数据"); //弹出一个带有确定按钮的对话框
} else {
//弹出带有两个按钮：确定和取消的对话框，如果点击【确定】则返回值为0，点击【取消】返回值为1
int isOk = JOptionPane.showConfirmDialog(null, "您确定要删除吗？", "删除确认",JOptionPane.YES_NO_OPTION);
if (isOk == 0) {
// 如果值是 0 ，说明点击了确定要删除
int selectedRow = jTable1.getSelectedRow(); // 获取选中行的索引
int id = (Integer) jTable1.getModel()
.getValueAt(selectedRow, 0); // 找到要删除的行的第一列，其实就是要删除的记录的主键
String sql = "delete from tb_order where id=" + id; // 拿到主键值后，组装出删除的sql语句
boolean zsg = BaseDao.zsg(sql); // 执行删除操作，并返回是否成功
if (zsg) {
JOptionPane.showMessageDialog(null, "删除成功！");
// 删除后，调用表格初始化的方法，重新加载数据，使表格加载显示最新数据：
initTable("select * from tb_order");
} else {
JOptionPane.showMessageDialog(null, "删除失败！");
}
}
}
}
Function 3: Add function
Implementation steps:
1. First create the [Add Form] interface by dragging and dropping, and set the default close property toDISPOSE
2. Click the [Add] button in the [Main Form], and use the code to open the [Add Form]:
Double-click on the [Add] button of ==[main form]==, automatically go to the place where the code is written, and write the code to open the new form: double-click the
blank area of the button above, and automatically enter the code area below:
write code as follows:
3. Write a handler on the [Confirm Add] button of [Add Form]:
After double-clicking the above button, it will automatically go to the following code:
Write the code as shown in the figure below:
Source code:
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
// 1. 获取所有文本框的数据
String name = jTextField1.getText(); // 获取商品名字。jTextField1是第一个输入框的名字（可以改名）
String price = jTextField2.getText(); // 获取价格
String oid = jTextField3.getText(); // 获取商品编号
String desc = jTextField4.getText(); // 获取商品描述
// 2.如果商品名、价格、商品编号有任意一个没填写，则给出提示
if ("".equals(name) || "".equals(price) || "".equals(oid)) {
JOptionPane.showMessageDialog(null, "请录入完整信息！");
}
// 3.如果所有的文本框都填写了，则进行插入操作：
else {
// 所有从文本输入框中获取到的内容都为String字符串类型，要想插入到数据库，必须与数据表中的数据类型一致。
// 因此，需要对价格进行转换（数据库表中价格字段是小数类型）
double pri = Double.parseDouble(price); // 将文本框获取的字符串转换为小数
// 拼装sql插入语句：
String sql = String.format(
"insert into tb_order values(null,'%s',%f,'%s','%s')",
name, pri, oid, desc);
if (BaseDao.zsg(sql)) {
// 真正的执行，并根据返回结果给出提示
JOptionPane.showMessageDialog(null, "新增商品成功！");
// this.setVisible(false); //隐藏当前窗体
this.dispose(); // 销毁当前窗体（即 关闭新增窗口）
} else {
JOptionPane.showMessageDialog(null, "新增商品失败！");
}
}
}
4. Back to home button
You can directly close the current form.
Double-click the button and write the following code: this.dispose(); // Destroy the current form (that is, close the newly added window)