Question

我有这个代码，我遇到了使用java netbeans从MySQL数据库读取信息的问题，数据库varchar中的数据类型

import com.mysql.jdbc.Statement;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.util.Scanner;

public class NewDataBase {
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        try{
              Connection con = DriverManager.getConnection("jdbc:mysql://localhost/mydb","root", "password");
              Statement stmt = (Statement) con.createStatement();
              System.out.println("Enter name");
              String name =sc.next();
              String SQL = "select * from list where Name ='"+ name + "'";
              ResultSet rs = stmt.executeQuery(SQL);
              System.out.print("Name: " + rs.getNString("Name"));
              System.out.print("Number: " + rs.getNString("Number"));
              // while(rs.next())
              // {
              //   System.out.print("Name: " + rs.getNString("Name"));
              //  System.out.print("Number: " + rs.getNString("Number"));

              //}
        }catch(Exception e){
            System.out.print("Error:" + e.getMessage());
        } 
    }
}

错误：当字段的字符集不是UTF-8时，无法调用getNString（）

Answer 1

尝试使用rs.getString("Name")代替rs.getNString("Name")。

Answer 2

使用：

    Properties props = new Properties(); 
    props.put("user", "root");         
    props.put("password", "password");
    props.put("useUnicode", "true");
    props.put("useServerPrepStmts", "false"); // use client-side prepared statement
    props.put("characterEncoding", "UTF-8"); // ensure charset is utf8 here

    String url = "jdbc:mysql://localhost/mydb";
    Connection connection = DriverManager.getConnection(url, props);

    PreparedStatement ps = 
        connection.prepareStatement("INSERT INTO list (Name, Number) VALUES (?, ?)");

    String testNumber = "12345";
    String testName = "name1";
    pstmt1.setNCharacterStream(1, new StringReader(testName), testName.length());
    ps.setNCharacterStream(2, new StringReader(testNumber), testNumber.length());
    ps.execute();

另外不要忘记在

中发表评论

if (rs.next()) {
    System.out.print("Name: " + rs.getNString("Name"));
    System.out.print("Number: " + rs.getNString("Number"));
}

Answer 3

我100％肯定这是有效的。我从Namberi那里得到了答案。

rs.getString("Name") instead of rs.getNString("Name")

Answer 4

if (rs.next()) {
    rs.getString("Name");
}
rs.close();
stmt.close();
con.close();

是的，最好使用PreparedStatement进行SQL注入并转义反斜杠，引用等。

我无法使用java netbeans从DB读取

4 个答案: