qae*_*osh 5 java arrays records arraylist data-structures
我需要得到一个具有3种类型值的变量类型,我知道这样做的唯一方法是"记录",但我知道Java中没有类似"记录"的类型ArrayList,但我不明白...
我的结果应该是:(不知道它在Java中看起来如何,所以我以不同的风格展示)
TData = Record
Username : String;
UserID : Int ;
RowID : Int;
end;
users : array[1..10] of TData;
for(int i = 1; i < rowCount; i++){
TData.Username[i] = rs.GetString("Name");
TData.UserID[i] = rs.GetInt("UserID");
TData.RowID[i] = row;
}
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关于如何制作这样的东西的任何建议?是ArrayList我真正需要的?
感谢您的帮助,最后我结合并得到了这个结果,完美地运作:
class MyData {
private String userName;
private int userID;
private int RowID;
public MyData(String userName, int userID, int RowID) {
this.userName = userName;
this.userID = userID;
this.RowID = RowID;
}
public String getUserName() {
return userName;
}
public int getUserID() {
return userID;
}
public int getRowID() {
return RowID;
}
}
public void AList(){
ArrayList<MyData> users = new ArrayList<>();
try{
conn = DBConnection.DBConnector();
pst = conn.prepareStatement("SELECT * FROM TableUserData");
rs = pst.executeQuery();
row = 0;
while (rs.next()) {
users.add(new MyData(rs.getString("User_name"), rs.getInt("ID"), row));
row++;
}
for (MyData tmp : users) {
JOptionPane.showMessageDialog(null, "Users: " + tmp.getUserName() + " row: " + rtmp.getRowID());
}
}catch(Exception e){
JOptionPane.showMessageDialog(null, "Arraylist error: " + e);
}
}
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你在混淆东西.
An ArrayList是数组的灵活替代品,用于存储具有相同类型的"一堆"数据.
这些数据的类型(一个条目)取决于您.
在Java中执行此操作的标准方法是定义类
class MyData {
private String userName;
private int userID;
private int rowID;
public MyData(String userName, int userID, int rowID) {
this.userName = userName;
this.userID = userID;
this.rowID = rowID;
}
public String getUserName() {
return userName;
}
public int getUserID() {
return userID;
}
public int getRowID() {
return rowID;
}
}
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然后
ArrayList<MyData> users = new ArrayList<>();
while (rs.next()) {
users.add(new MyData(rs.GetString("Name"), rs.GetInt("UserID"), rs.GetInt("RowID")));
}
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