JavaWeb 使用DBUtils實現增刪改查方式
JavaWeb 使用DBUtils實現增刪改查
1、創建C3p0Utils類
創建cn.itcast.jdbc.utils包
代碼如下:
package cn.itcast.jdbc.utils; import javax.sql.DataSource; import com.mchange.v2.c3p0.ComboPooledDataSource; public class C3p0Utils { private static DataSource ds; static { ds = new ComboPooledDataSource(); } public static DataSource getDataSource() { return ds; } }
2、創建DBUtilsDao類
在src目錄下,創建一個cn.itcast.jdbc.demo的包,在該包下創建一個DBUtilsDao類
代碼如下:
package cn.itcast.jdbc.demo; import java.sql.SQLException; import java.util.List; import org.apache.commons.dbutils.QueryRunner; import org.apache.commons.dbutils.handlers.BeanHandler; import org.apache.commons.dbutils.handlers.BeanListHandler; import cn.itcast.chapter10.example.User; import cn.itcast.jdbc.utils.C3p0Utils; public class DBUtilsDao { // 查詢所有,返回List集合 public List findAll() throws SQLException { // 創建QueryRunner對象 QueryRunner runner = new QueryRunner(C3p0Utils.getDataSource()); // 寫SQL語句 String sql = "select * from user"; // 調用方法 List list = (List) runner.query(sql, new BeanListHandler(User.class)); return list; } // 查詢單個,返回對象 public User find(int id) throws SQLException { // 創建QueryRunner對象 QueryRunner runner = new QueryRunner(C3p0Utils.getDataSource()); // 寫SQL語句 String sql = "select * from user where id=?"; // 調用方法 User user = (User) runner.query(sql, new BeanHandler(User.class), new Object[] { id }); return user; } // 添加用戶的操作 public Boolean insert(User user) throws SQLException { // 創建QueryRunner對象 QueryRunner runner = new QueryRunner(C3p0Utils.getDataSource()); // 寫SQL語句 String sql = "insert into user (name,password) values (?,?)"; // 調用方法 int num = runner.update(sql, new Object[] { user.getName(), user.getPassword() }); if (num > 0) return true; return false; } // 修改用戶的操作 public Boolean update(User user) throws SQLException { // 創建QueryRunner對象 QueryRunner runner = new QueryRunner(C3p0Utils.getDataSource()); // 寫SQL語句 String sql = "update user set name=?,password=? where id=?"; // 調用方法 int num = runner.update(sql, new Object[] { user.getName(), user.getPassword(),user.getId() }); if (num > 0) return true; return false; } // 刪除用戶的操作 public Boolean delete(int id) throws SQLException { // 創建QueryRunner對象 QueryRunner runner = new QueryRunner(C3p0Utils.getDataSource()); // 寫SQL語句 String sql = "delete from user where id=?"; // 調用方法 int num = runner.update(sql, id); if (num > 0) return true; return false; } }
3、創建測試類
在cn.itcast.jdbc.demo包中創建測試類DBUtilsDaoTest類
代碼如下:
package cn.itcast.jdbc.demo; import java.sql.SQLException; import java.util.List; import cn.itcast.chapter10.example.User; public class DBUtilsDaoTest1 { private static DBUtilsDao dao = new DBUtilsDao(); public static void testInsert() throws SQLException { User user = new User(); user.setName("zhaoliu"); user.setPassword("666666"); boolean b = dao.insert(user); System.out.println("testInsert:"+b); } public static void testupdate() throws SQLException { User user = new User(); user.setName("zhaoqi"); user.setPassword("666777"); user.setId(1); boolean b = dao.update(user); System.out.println("testupdate:"+b); } public static void testdelete() throws SQLException { boolean b = dao.delete(4); System.out.println("testdelete:"+b); } public static void testfindById() throws SQLException { User user = dao.find(2); System.out.println(user.getId() + "," + user.getName() + "," + user.getPassword()); } public static void testfindAll() throws SQLException { List<User> list = dao.findAll(); for(User user : list) { System.out.println(user.getId() + "," + user.getName() + "," + user.getPassword()); } } public static void main(String[] args) throws SQLException { testInsert(); testupdate(); testdelete(); testfindById(); testfindAll(); } }
以上代碼由多個測試函數組成,依次為:插入、修改、刪除、根據id查詢、查詢所有
4、執行測試類
1.數據表user原始數據如下:
執行後結果如下:
之中插入和刪除都是針對第四個數據進行的操作,所以沒有顯現
Java DBUtils技術訪問數據庫
DBUtils
Dbutils是操作數據庫的組件,對傳統操作數據庫的類進行二次封裝,可以把結果集轉化成List。
介紹
DBUtils相對以往的連接數據庫得到結果集的模式,代碼更加簡潔,訪問更加迅速,這裡我對一個我自級設計的Cuisine表做一個簡單的例子。
對數據庫的查詢語句的代碼
對已有的菜系表Cuisine查找對應菜系編號cuid的全部數據.
1、菜系表的實體類
// 菜系表的實體類 public class Cuisine { private static final long serialVersionUID = 1L; private int cuid; private String cuname; public Cuisine() { super(); // TODO Auto-generated constructor stub this.cuid = 0; this.cuname = ""; } public Cuisine(int cuid, String cuname) { super(); this.cuid = cuid; this.cuname = cuname; } public int getCuid() { return cuid; } public void setCuid(int cuid) { this.cuid = cuid; } public String getCuname() { return cuname; } public void setCuname(String cuname) { this.cuname = cuname; } @Override public String toString() { return "Cuisine [cuid=" + cuid + ", cuname=" + cuname + "]"; } }
2、實現數據查詢的方法
// 實現數據查詢 public Cuisine getCuisine(Cuisine cu) {//得到對應菜系的信息 // TODO Auto-generated method stub QueryRunner queryRunner = new QueryRunner(); if(cu.getCuid() != 0){ String sql = "select * from cuisine where cuid = ?"; try { return queryRunner.query(DBUtilsPro.getConnection(),sql,cu.getCuid(),new BeanHandler(Cuisine.class)); } catch (SQLException e) { // TODO Auto-generated catch block e1.printStackTrace(); } } return null; }
以上為個人經驗,希望能給大傢一個參考,也希望大傢多多支持WalkonNet。
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