关于#mysql#的问题：n = pstm.executeUpdate()

Question

######后台成功添加数据，但是数据库信息没有显示

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package edu.sdp.dao;

import edu.sdp.model.Readers;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * 读者的数据访问层代码，实现对读者数据的增删改查
 *
 * @author Administrator
 */
public class ReadersDao {

    private Connection conn;
    private PreparedStatement pstm;
    private ResultSet rs;
    private String url = "jdbc:mysql://localhost:3306/SDPLibraryData?useUnicode=true&characterEncoding=utf-8";
    private String user = "root";
    private String password = "root";

    public ReadersDao() {
        try {
            //初始化数据库连接对象conn
            conn = DriverManager.getConnection(url, user, password);
        } catch (SQLException ex) {
            Logger.getLogger(ReadersDao.class.getName()).log(Level.SEVERE, null, ex);
        }

    }

    public int add(Readers model) {
        int n = -1;

        try {

            //数据库连接对象，正常是支持自动提交的，如果想启动事物，需要关闭它
            conn.setAutoCommit(false);

            String sql = "insert into Concats "
                    + "(RealName,Sex,Birthday,Mobile,Address,StateId)"
                    + " values "
                    + "(?,?,?,?,?,?)";
            pstm = conn.prepareStatement(sql, PreparedStatement.RETURN_GENERATED_KEYS);
            //参数化数据
            pstm.setString(1, model.getRealName());
            pstm.setString(2, model.getSex());
            pstm.setDate(3, model.getBirthday());
            pstm.setString(4, model.getMobile());
            pstm.setString(5, model.getAddress());
            pstm.setInt(6, model.getStateId());
            //执行SQL语句并获取影响行数
            n = pstm.executeUpdate();
            if (n > 0) {

                //获取刚刚插入的记录的主键--begin
                int concatId = -1;
                ResultSet rs = pstm.getGeneratedKeys();
                if (rs.next()) {
                    concatId = rs.getInt(1);
                }
                System.out.println("联系人编号：" + concatId);
                rs.close();
                //获取刚刚插入的记录的主键---end

                sql = "insert into Readers "
                        + "(ReaderNumber,ConcatId,BorrowNumber,BorrowDays,StateId)"
                        + " values "
                        + "(?,?,?,?,?)";
                pstm = conn.prepareStatement(sql);
                //参数化数据
                pstm.setString(1, model.getReaderNumber());
                pstm.setInt(2, concatId);
                pstm.setInt(3, model.getBorrowNumber());
                pstm.setInt(4, model.getBorrowDays());
                pstm.setInt(5, model.getStateId());
                n = pstm.executeUpdate();
               conn.commit();//手动提交（结束事物）
              
            } else {
                System.out.println("基本信息新增失败！");
                conn.rollback();//回滚事务
            }
          
            pstm.close();
            conn.close();

        } catch (SQLException ex) {
            Logger.getLogger(ReadersDao.class.getName()).log(Level.SEVERE, null, ex);
        }

        return n;
    }

}

运行结果及详细报错内容

数据添加成功，但是没有在数据库中显示

Answer 1

如果n大于0，那么数据库中确实是修改成功了的。
看到你的程序中有两个插入操作，可以先检查下两次返回的n是否都大于0，如果是，那就可能只是在检查数据时有一些问题，比如使用界面化工具查看数据表的时候没有进行刷新，可以使用sql查询直接检验。如果有帮助请采纳~