mvc的增删改查

最新推荐文章于 2023-07-04 13:15:55 发布

LIN_17970

最新推荐文章于 2023-07-04 13:15:55 发布

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CC 4.0 BY-SA版权

分类专栏： MVC 文章标签： mvc的增删改查

本文链接：https://blog.youkuaiyun.com/LIN_17970/article/details/91403219

本文档详细介绍了如何通过MVC模式进行数据库的增删改查操作，包括建立数据库连接、创建实体类、定义DAO方法、编写控制器、测试类以及配置mvc.xml和web.xml文件，最后展示了在JSP页面上实现的功能。

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1.首先要建立连接

package com.zking.mvcplus.util;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;
/**
 * 提供了一组获得或关闭数据库对象的方法
 * 
 */
public class DBAccess {
   
   
 private static String url;
 private static String driver;
 private static String user;
 private static String password;
 static {
   
   // 静态块执行一次，加载 驱动一次
  try {
   
   
   InputStream is = DBAccess.class
     .getResourceAsStream("config.properties");
   Properties properties = new Properties();
   properties.load(is);
   driver = properties.getProperty("driver");
   url = properties.getProperty("url");
   user = properties.getProperty("user");
   password = properties.getProperty("pwd");
   Class.forName(driver);
  } catch (Exception e) {
   
   
   e.printStackTrace();
   throw new RuntimeException(e);
  }
 }
 /**
  * 获得数据连接对象
  * 
  * @return
  */
 public static Connection getConnection() {
   
   
  try {
   
   
   Connection conn = DriverManager.getConnection(url, user, password);
   return conn;
  } catch (SQLException e) {
   
   
   e.printStackTrace();
   throw new RuntimeException(e);
  }
 }
 public static void close(ResultSet rs) {
   
   
  if (null != rs) {
   
   
   try {
   
   
    rs.close();
   } catch (SQLException e) {
   
   
    e.printStackTrace();
    throw new RuntimeException(e);
   }
  }
 }
 public static void close(Statement stmt) {
   
   
  if (null != stmt) {
   
   
   try {
   
   
    stmt.close();
   } catch (SQLException e) {
   
   
    e.printStackTrace();
    throw new RuntimeException(e);
   }
  }
 }
 public static void close(Connection conn) {
   
   
  if (null != conn) {
   
   
   try {
   
   
    conn.close();
   } catch (SQLException e) {
   
   
    e.printStackTrace();
    throw new RuntimeException(e);
   }
  }
 }
 public static void close(Connection conn, Statement stmt, ResultSet rs) {
   
   
  close(rs);
  close(stmt);
  close(conn);
 }
 public static boolean isOracle() {
   
   
  return "oracle.jdbc.driver.OracleDriver".equals(driver);
 }
 public static boolean isSQLServer() {
   
   
  return "com.microsoft.sqlserver.jdbc.SQLServerDriver".equals(driver);
 }
 public static boolean isMysql() {
   
   
  return "com.mysql.jdbc.Driver".equals(driver);
 }
 public static void main(String[] args) {
   
   
  Connection conn = DBAccess.getConnection();
  DBAccess.close(conn);
  System.out.println("isOracle：" + isOracle());
  System.out.println("isSQLServer：" + isSQLServer());
  System.out.println("isMysql：" + isMysql());
  System.out.println("数据库连接(关闭)成功");
 }
}

2.建个连接到数据库实体类book


package com.zking.mvcplus.entity;
public class Book {
   
   
 private int bid;
 private String bname;
 private float price;
 @Override
 public String toString() {
   
   
  return "Book [bid=" + bid + ", bname=" + bname + ", price=" + price + "]";
 }
 public int getBid() {
   
   
  return bid;
 }
 public void setBid(int bid) {
   
   
  this.bid = bid;
 }
 public String getBname() {
   
   
  return bname;
 }
 public void setBname(String bname) {
   
   
  this.bname = bname;
 }
 public float getPrice() {
   
   
  return price;
 }
 public void setPrice(float price) {
   
   
  this.price = price;
 }
 public Book(int bid, String bname, float price)