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有人可以看看这个并告诉我为什么我会收到这个错误。我正在尝试从 Mysql 数据库中提取表并将其打印到文本文件中。我给了我上面列出的错误。

package db;

import java.io.*;
import java.sql.*;
import java.util.*;

public class TableToTextFile {
    public static void main(String[] args) {
        List<int[]> data = new ArrayList();

        try {
            Connection con = null;
            Class.forName("com.mysql.jdbc.Driver");
            con = DriverManager.getConnection(
                    "jdbc:mysql://localhost:3306/test", "root", "root");
            Statement st = con.createStatement();
            ResultSet rs = st.executeQuery("Select * from employee");

            while (rs.next()) {
                String id = rs.getString("emp_id");
                String name = rs.getString("emp_name");
                String address = rs.getString("emp_address");
                String contactNo = rs.getString("contactNo");
                data.add(id + " " + name + " " + address + " " + contactNo);

            }
            writeToFile(data, "Employee.txt");
            rs.close();
            st.close();
        } catch (Exception e) {
            System.out.println(e);
        }
    }

    private static void writeToFile(java.util.List list, String path) {
        BufferedWriter out = null;
        try {
            File file = new File(path);
            out = new BufferedWriter(new FileWriter(file, true));
            for (String s : list) {
                out.write(s);
                out.newLine();

            }
            out.close();
        } catch (IOException e) {
        }
    }
}
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1 回答 1

4

可能是因为您的列表已被声明为接受整数数组并且您正在传递一个字符串。

List<int[]> data = new ArrayList();

改为接受字符串。

List<String> data = new ArrayList<>();

一个更好、更面向对象的设计是创建一个名为Employee并使用它的类。

public class Employee {
    private String id;
    private String name;
    ...
}

List<Employee> data = new ArrayList<>();
于 2012-08-12T23:15:43.083 回答