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##关于jdbc的增删改查
思想 1.创建接口 com.dao userdao 2.创建实现类 com.dao.impl userdaoimpl 3.创建实现类 com.test testuserdaoimpl 4.创建工具类 jdbcutil 5.创建关于mysql数据库连接1.public interface UserDao {
//查询void findAll();//传入参数进行验证//登录//String sql = select *from t_user where username = '" + username+"'and password = '"password"'void login(String username, String password);//进行插入void inert(String username ,String password);//删除void delete(int id);//更新public void update(int id ,String name);
}
package com.dao.impl;
import java.sql.Connection;
import java.sql.PreparedStatement; import java.sql.ResultSet; import java.sql.Statement;import org.junit.Test;
import com.dao.UserDao;
import com.util.JDBCUtil;
public class UserDaoImpl implements UserDao{
//查@Overridepublic void findAll() { Connection conn = null; Statement st = null; ResultSet rs = null; try { // TODO Auto-generated method stub conn = JDBCUtil.getConn(); st = conn.createStatement(); String sql = "select *from t_user"; rs = st.executeQuery(sql); while(rs.next()) { int id = rs.getInt("id"); String username = rs.getString("username"); String password = rs.getString("password"); System.out.println(id + username + password); } } catch (Exception e) { // TODO: handle exception e.printStackTrace(); }finally { JDBCUtil.release(conn, st, rs); }}//登录@Overridepublic void login(String username, String password) { // TODO Auto-generated method stub Connection conn = null; Statement st = null; ResultSet rs = null; try { conn = JDBCUtil.getConn(); String sql = "select *from t_user where username = ? and password =?"; //预先对sql语句进行预加载 PreparedStatement ps = conn.prepareStatement(sql); ps.setString(1, username); ps.setString(2, password); rs = ps.executeQuery(); if(rs.next()) { System.out.println("登陆成功"); }else { System.out.println("登录失败"); } } catch (Exception e) { e.printStackTrace(); } finally { JDBCUtil.release(conn, st, rs); } }//插入@Overridepublic void inert(String username, String password) { Connection conn = null; PreparedStatement ps = null; try { conn = JDBCUtil.getConn(); String sql = "insert into t_user values(null,?,?)"; ps = conn.prepareStatement(sql); ps.setString(1, username); ps.setString(2, password); int result = ps.executeUpdate(); if(result>0) { System.out.println("执行成功"); } else { System.out.println("执行失败"); } } catch (Exception e) { // TODO: handle exception e.printStackTrace(); }finally { JDBCUtil.release(conn, ps); }}//删除@Overridepublic void delete(int id) { Connection conn = null; PreparedStatement ps = null; try { // TODO Auto-generated method stub conn = JDBCUtil.getConn(); String sql = "delete from t_user where id= ?"; ps = conn.prepareStatement(sql); ps.setInt(1, id); int result = ps.executeUpdate(); if(result >0) { System.out.println("删除成功"); }else { System.out.println("删除失败"); } } catch (Exception e) { e.printStackTrace();} finally { JDBCUtil.release(conn, ps); }}/* * @Override public void login(String username, String password) { Connection * conn = null; Statement st = null; ResultSet rs = null; try { // TODO * Auto-generated method stub conn = JDBCUtil.getConn(); st = * conn.createStatement(); String sql = "select *from t_user where username = '" * + username + "' and password = '" + password + "'"; rs = * st.executeQuery(sql); if (rs.next()) { System.out.println("登陆成功"); } else { * System.out.println("登陆失败"); } } catch (Exception e) { e.printStackTrace(); } * finally { JDBCUtil.release(conn, st, rs); } } */@Overridepublic void update(int id, String name) { // TODO Auto-generated method stub Connection conn = null; PreparedStatement ps = null; try { conn = JDBCUtil.getConn(); String sql = "update t_user set username = ? where id = ?"; ps = conn.prepareStatement(sql); ps.setString(1,name); ps.setInt(2, id); int result = ps.executeUpdate(); if(result >0) { System.out.println("更新成功"); }else { System.out.println("更新失败"); } } catch (Exception e) { // TODO: handle exception e.printStackTrace(); }finally { JDBCUtil.release(conn, ps); }} }
package com.test;
import org.junit.Test;
import com.dao.UserDao;
import com.dao.impl.UserDaoImpl;public class TestUserDaoImpl {
@Testpublic void testFindAll() { UserDao dao = new UserDaoImpl(); dao.findAll();}@Testpublic void testLogin() { UserDao dao = new UserDaoImpl(); //dao.login("admin", "10086"); dao.login("admin", "10086SAA");}@Testpublic void testInsert() { UserDao dao = new UserDaoImpl(); dao.inert("lisi", "123456");}@Testpublic void testDelete() { UserDao dao = new UserDaoImpl(); dao.delete(3);}@Testpublic void testUpdate() { UserDao dao = new UserDaoImpl(); dao.update(1, "wangbaoqaing");} }
package com.util;
//jdbc.properties没有导包
import java.io.FileInputStream; 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;public class JDBCUtil {
//创建4个静态对象static String driverClass = null;static String url = null;static String name = null;static String password = null;//创建静态代码块static { try { Properties properties = new Properties(); InputStream is = new FileInputStream("jdbc.properties"); //导入流 properties.load(is); //进行对对象进行赋值 driverClass = properties.getProperty("driverClass"); url = properties.getProperty("url"); name = properties.getProperty("name"); password = properties.getProperty("password"); } catch (Exception e) { e.printStackTrace(); }}//获取连接对象public static Connection getConn() { Connection conn = null; try { Class.forName(driverClass); conn = DriverManager.getConnection(url, name, password); } catch (Exception e) { // TODO: handle exception e.printStackTrace(); } return conn; }//释放资源public static void release(Connection conn,Statement st,ResultSet rs) { closeConn(conn); closeSt(st); closeRs(rs);}public static void release(Connection conn, Statement st) { }private static void closeRs(ResultSet rs) { try { if(rs != null){ rs.close(); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); }finally { rs= null; } }private static void closeSt(Statement st) { // TODO Auto-generated method stub try { if(st != null){ st.close(); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); }finally { st= null; }}private static void closeConn(Connection conn) { // TODO Auto-generated method stub try { if(conn != null){ conn.close(); } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); }finally { conn= null; }} }
5. driverClass = com.mysql.cj.jdbc.Driver url = jdbc:mysql://localhost/user name = root password = admin关于mysql数据的jar文件
其他的地方应该有，转载地址：http://ndgwi.baihongyu.com/