我做了一个小应用程序，它读入了Excel文件。我将它连接到我的MySQL数据库，以便我可以将文件放入包含多个表的数据库中。但是，在将值应用到“订单”中时表，有一个SQLException，值不进入数据库。这是CustomerMC类中的例外。 ＆＃39;客户＆＃39;的价值观。 table进入数据库。
我所拥有的代码包含一个main，我读取文件并生成Customer和Order的实例，两个容器类，其中包含值，一个与此无关的连接类，以及一个Customer类的Customer查询所在的位置。
主：
public static void main(String[] args){
CustomerMC cmc = new CustomerMC();
ArrayList<Customer> customers = new ArrayList<>();
ArrayList<Order> orders = new ArrayList<>();
try {
try (FileInputStream file = new FileInputStream(new File("C:/Users/Wout/Desktop/ProjectTest.xlsx"))) {
XSSFWorkbook wb = new XSSFWorkbook(file);
XSSFSheet sh = wb.getSheetAt(0);
Iterator<Row> rowIterator = sh.iterator();
while(rowIterator.hasNext()) {
Row row = rowIterator.next();
Iterator<Cell> cellIterator = row.cellIterator();
int counter = 0;
int cid = 0;
int OrderID = 0;
String name = "";
String purchase = "";
String age = "";
String product = "";
while (cellIterator.hasNext() && row.getRowNum() != 0) {
Cell cell = cellIterator.next();
counter++;
switch (counter) {
case 1:
cid = (int)cell.getNumericCellValue();
break;
case 2:
name = cell.getStringCellValue();
break;
case 3:
purchase = cell.getStringCellValue();
break;
case 4:
age = "" + cell.getNumericCellValue();
break;
case 5:
OrderID = (int)cell.getNumericCellValue();
break;
case 6:
product = "" + cell.getStringCellValue();
break;
case 7:
cid = (int)cell.getNumericCellValue();
break;
}
}
if(row.getRowNum() != 0) {
Customer customer = new Customer(cid,name,purchase,age);
Order order = new Order(OrderID, product, cid);
customers.add(customer);
orders.add(order);
}
}
}
} catch (FileNotFoundException ex) {
System.out.println("File has not been found");
} catch (IOException ex) {
System.out.println("IOException");
}
for(Order order : orders) {
System.out.println(order.toString());
cmc.insertOrder(""+order.getOrderid(), order.getProduct(), ""+order.getCid());
}
for(Customer customer : customers){
System.out.println(customer.toString());
cmc.insertCustomer(""+customer.getCid(), customer.getName(), customer.getPurchase(), customer.getAge());
}
}
容器类：
public class Customer {
private int cid;
private String name;
private String purchase;
private String age;
public Customer(int cid, String name, String purchase, String age) {
this.cid = cid;
this.name = name;
this.purchase = purchase;
this.age = age;
}
public int getCid() {
return cid;
}
public void setCid(int cid) {
this.cid = cid;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPurchase() {
return purchase;
}
public void setPurchase(String purchase) {
this.purchase = purchase;
}
public String getAge() {
return age;
}
public void setAge(String age) {
this.age = age;
}
@Override
public String toString() {
return "" + cid + " ; "+ name + " ; " + purchase + " ; " + age;
}
public class Order {
private int orderid;
private String product;
private int cid;
public Order(int orderid, String product, int cid) {
this.orderid = orderid;
this.product = product;
this.cid = cid;
}
public int getOrderid() {
return orderid;
}
public void setOrderid(int orderid) {
this.orderid = orderid;
}
public String getProduct() {
return product;
}
public void setProduct(String product) {
this.product = product;
}
public int getCid() {
return cid;
}
public void setCid(int cid) {
this.cid = cid;
}
@Override
public String toString() {
return "" + orderid + " ; " + product + " ; " + cid;
}
客户模型类：
public class CustomerMC {
private Connection connection;
private PreparedStatement pst;
String query;
ResultSet rs;
public CustomerMC(){
try{
connection = SimpleDataSourceV2.getConnection();
}
catch(SQLException e){
System.out.println("Connection failure");
e.printStackTrace();
}
}
public String insertCustomer(String cid, String name, String purchase, String age) {
String returning = null;
try {
query = "insert into CustomerService values(?,?,?,?);";
pst = connection.prepareStatement(query);
pst.setInt(1, Integer.parseInt(cid));
pst.setString(2, name);
pst.setString(3, purchase);
pst.setString(4, age);
int response = pst.executeUpdate();
returning = response +" Records has/have been edited";
} catch (SQLException e) {
returning = "An error has occured";
System.out.println(returning);
}
return returning;
}
public String insertOrder(String orderid, String product, String id) {
String returning = null;
try {
query = "insert into CustomerService values(?,?,?,?);";
pst = connection.prepareStatement(query);
pst.setInt(1, Integer.parseInt(orderid));
pst.setString(2, product);
pst.setInt(3, Integer.parseInt(id));
int response = pst.executeUpdate();
returning = response +" Records has/have been edited";
} catch (SQLException e) {
returning = "xx";
System.out.println(returning);
}
return returning;
}
显然还有一个类与数据库连接。这与这个问题无关，所以我决定不予考虑。
然后我的Excel表格是一张简单的表格，其中cid，名称，购买者和年龄是＆＃39;客户＆＃39; table和OrderID，Product和cid是＆＃39; Orders＆＃39;表。订单中的Cid是客户的外键。 Excel会自动生成该字段，作为在customers表中获取的值。我重新实现了cid值，使自己更容易。
运行后我得到的输出如下：
1 ; Monitor ; 1
java.sql.SQLException: Column count doesn't match value count at row 1
2 ; Couch ; 2
3 ; Appartment ; 3
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1074)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4120)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4052)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2503)
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2664)
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2794)
at
com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:2155)
at
com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2458)
at
com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2375)
at
com.mysql.jdbc.PreparedStatement.executeUpdate(PreparedStatement.java:2359)
at p4project.CustomerMC.insertOrder(CustomerMC.java:66)
at p4project.Main.main(Main.java:103)
java.sql.SQLException: Column count doesn't match value count at row 1
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1074)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4120)
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:4052)
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2503)
我不知道为什么第二张桌子没有实施，我希望有人可以提供帮助！任何帮助表示赞赏。
答案 0 :(得分：1)
您的例外情况是：CustomerMC.insertOrder(CustomerMC.java:66)并且说
java.sql.SQLException: Column count doesn't match value count。
您的CustomerService表似乎有7列，但您想插入只有4个值的行。这是不可能的。您必须为每列提供一个值（如果您没有指定要插入值的列的名称）。如果您的架构允许，您也可以插入空值，但您必须指定它。该语句不知道您希望将哪些列留空。