Java针对数据库增删改查代码

package com.bank.abc;

import java.beans.PropertyVetoException;
import java.sql.Connection;
import java.sql.DatabaseMetaData;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.List;

import com.mchange.v2.c3p0.ComboPooledDataSource;

//封装银行卡表的数据库操作类

public class CardDAO {
    
    //添加卡
    public String addCard(String name,String shenfen ,double balance)
    {
        String rnt=null;
        //生成卡号
        String cardid=(int)(Math.random()*1000000)+"";
        
        //保存数据
        try{
        //1加载驱动
        Class.forName("oracle.jdbc.driver.OracleDriver");
    
        //2获得连接
        Connection conn=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:orcl","test01","123456");
        
        //3创建声明
        Statement st=conn.createStatement();
        //4执行语句
        String sql="insert into bank values('"+name+"','"+shenfen+"','"+cardid+"','"+balance+"')";
        if(st.executeUpdate(sql)>0)
        {
            return cardid;
        }
        //5释放资源
        st.close();
        conn.close();
        }catch(Exception e){
            e.printStackTrace();
            
        }
        
        return rnt;
    }
    //修改余额
    //可以完成取款和存款的功能
    public boolean updateBalance(String cardid,double balance)throws Exception
    {
        boolean rtn=false;
        try{
            if(balance<0)
            {
                throw new Exception("余额数据异常");
            }
            
            //1加载驱动
            Class.forName("oracle.jdbc.driver.OracleDriver");
        
            //2获得连接
            Connection conn=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:orcl","test01","123456");
            
            //3创建声明
            Statement st=conn.createStatement();
            //4执行语句
            String sql="update bank set ba_balance='"+balance+"'where ba_card='"+cardid+"'";
            rtn=st.executeUpdate(sql)==1;
            
            //5释放资源
            st.close();
            conn.close();
            
            }catch(Exception e){
                e.printStackTrace();
                
            }
        return rtn;
    }
    
    //验证登录
    public boolean login(String cardid,String password)
    {
            boolean rtn=false;
            try{
                //1加载驱动
                Class.forName("oracle.jdbc.driver.OracleDriver");
            
                //2获得连接
                Connection conn=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:orcl","test01","123456");
                
                //3创建声明
                Statement st=conn.createStatement();
                //4执行语句
                String sql="select ba_card,ba_password from bank where ba_card='"+cardid+"'ba_password='"+password+"'";
                ResultSet rs=st.executeQuery(sql);
                
                rtn=rs.next();
                //5释放资源
                st.close();
                conn.close();
                
                }catch(Exception e){
                    e.printStackTrace();
                    
                }
                return rtn;
    }
    
    //验证登录
    public boolean login1(String cardid,String password)
    {
        boolean rtn=false;
        
        try{
            Class.forName("oracle.jdbc.driver.OracleDriver");
            
            Connection conn=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:orcl","test01","123456");
            //带有？占位符的语句
            String sql="select * from bank where ba_card=? and ba_password=?";
            
            //预编译声明
            //优点：1执行效率高，2避免SQL注入
            PreparedStatement ps=conn.prepareStatement(sql);
            //替换占位符
            ps.setString(1, cardid);
            ps.setString(2, password);
            
            ResultSet rs=ps.executeQuery();
            //如果有数据就验证通过
            rtn=rs.next();
            
            //数据库元数据
            DatabaseMetaData dm= conn.getMetaData();
            System.out.println("getURL="+dm.getURL());
            System.out.println("getUserName="+dm.getUserName());
            System.out.println("getDatabaseProductName="+dm.getDatabaseProductName());
            
            //结果集的元数据
            ResultSetMetaData rsd=rs.getMetaData();
            System.out.println("getColumnCount="+rsd.getColumnCount());
            System.out.println("getColumnName"+rsd.getColumnName(3));
            
            rs.close();
            ps.close();
            conn.close();
        }catch(Exception e)
        {
            e.printStackTrace();
        }
        
        
        return rtn;
    }
    
    //转账
    public boolean zhuanzhang(String cardid_out ,String cardid_in ,double money)
    {
        boolean rtn=false;
        Connection conn=null;
        PreparedStatement ps=null;
        //
        try {
            Class.forName("oracle.jdbc.driver.OracleDriver");
            
            conn=DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:orcl","test01","123456");
            
            //连接自动提交默认为true
            //1.设置连接自动提交为false
            conn.setAutoCommit(false);
            
            //转出账户
        
            String sql="update bank set ba_balance=ba_balance-"+money+"where ba_card=?";
            
            ps=conn.prepareStatement(sql);
            
            ps.setString(1, cardid_out);
            
            rtn=ps.executeUpdate()==1;
            
            
            //模拟发生异常
            if(rtn)
            {
            throw new RuntimeException("网络中断");
            }
            //转入账户
             sql="update bank set ba_balance=ba_balance+"+money+"where ba_card=?";
            
            ps=conn.prepareStatement(sql);
            
            ps.setString(1, cardid_in);
            
            rtn=ps.executeUpdate()==1;
            
            //2提交事务
            conn.commit();
            
            
            
        } catch (Exception e) {
            // 3.回滚事务
            try {
                conn.rollback();
            } catch (SQLException e1) {
                e1.printStackTrace();
            }
            e.printStackTrace();
        }
        finally
        {
            try {
                ps.close();
                conn.close();
            } catch (SQLException e) {
                // TODO 自动生成的 catch 块
                e.printStackTrace();
            }
            
        }
        
        return rtn;
    }
    
    //测试连接池
    public void testC3P0()
    {
        //连接池的形式是DataSource
        //构建连接池对象
        ComboPooledDataSource cp=new ComboPooledDataSource();
        
        //配置连接池
        try {
            //设置驱动
            cp.setDriverClass("oracle.jdbc.driver.OracleDriver");
            //设置url
            cp.setJdbcUrl("jdbc:oracle:thin:@localhost:1521:orcl");
            //设置用户
            cp.setUser("test01");
            //设置密码
            cp.setPassword("123456");
            //设置连接最小数量
            cp.setMinPoolSize(5);
            //设置连接最大数量
            cp.setMaxPoolSize(20);
            //设置初始连接数量
            cp.setInitialPoolSize(5);
            
            
            Connection conn=cp.getConnection();
            
            String cardid=(int)(Math.random()*1000000)+"";
            
            String sql="insert into bank(ba_name,ba_shenfen,ba_card,ba_balance,ba_password)"+
            "values(?,?,?,?,?)";
            
            PreparedStatement ps=conn.prepareStatement(sql);
            
            ps.setString(1, "张三");
            ps.setString(2, "123456789012345678");
            ps.setString(3, cardid);
            ps.setDouble(4, 100);
            ps.setString(5, "123456");
            
            ps.executeUpdate();
            
            System.out.println("添加成功");
            
            ps.close();
            conn.close();
            
        } catch (Exception e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }
    }
    
    
    //测试连接池
    //通过配置文件，构建连接池
    //连接池的形式是DataSource
    //构建连接池对象
    ComboPooledDataSource cp=new ComboPooledDataSource("helloc3p0");
    
    public void test1C3P0()
    {
            
        //配置连接池
        try {
            
            
            
            Connection conn=cp.getConnection();
            
            String cardid=(int)(Math.random()*1000000)+"";
            
            String sql="insert into bank(ba_name,ba_shenfen,ba_card,ba_balance,ba_password)"+
            "values(?,?,?,?,?)";
            
            PreparedStatement ps=conn.prepareStatement(sql);
            
            ps.setString(1, "李四");
            ps.setString(2, "123456789012345678");
            ps.setString(3, cardid);
            ps.setDouble(4, 100);
            ps.setString(5, "123456");
            
            ps.executeUpdate();
            
            System.out.println("添加成功");
            
            ps.close();
            conn.close();
            
        } catch (Exception e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }
    }
    
    //查询账户,获取账户信息
    //返回实体类装载的数据
    public bank getcard(String cardid)
    {
        bank ba=null;
        try {
            Connection conn=cp.getConnection();
            
            String sql="select * from bank where ba_card=?";
            
            PreparedStatement ps=conn.prepareStatement(sql);
            
            ps.setString(1, cardid);
            
            ResultSet rs=ps.executeQuery();
            
            if(rs.next())
            {
                //使用实体类装载数据
                ba=new bank();
                ba.setBa_card(rs.getString("ba_card"));
                ba.setBa_name(rs.getString("ba_name"));
                ba.setBa_shenfen(rs.getString("ba_shenfen"));
                ba.setBa_balance(rs.getDouble("ba_balance"));
                ba.setBa_password(rs.getString("ba_password"));
                
                rs.close();
                ps.close();
                conn.close();
            }
        } catch (SQLException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }
        
        
        return ba;
        
    }
    
    //查询所有记录
    public List<bank> getAll()
    {
        List<bank> li=new ArrayList<>();
        try {
            Connection conn=cp.getConnection();
            
            Statement st=conn.createStatement();
            
            ResultSet rs=st.executeQuery("select * from bank");
            
            while(rs.next())
            {
                bank ba=new bank();
                ba.setBa_card(rs.getString("ba_card"));
                ba.setBa_name(rs.getString("ba_name"));
                ba.setBa_shenfen(rs.getString("ba_shenfen"));
                ba.setBa_balance(rs.getDouble("ba_balance"));
                ba.setBa_password(rs.getString("ba_password"));
                
                li.add(ba);
            }
            
            rs.close();
            st.close();
            conn.close();
            
        } catch (SQLException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }
        return li;
    }

}

测试：

package com.bank.abc;

import static org.junit.Assert.*;

import java.util.List;

import org.junit.Test;

public class testatm {

    @Test
    public void testInsert() {
        
        //测试发卡
        CardDAO cd=new CardDAO();
        String cardid=cd.addCard("李凯", "220521199202025439", 0);
        if(cardid !=null)
        {
            System.out.println("卡号"+cardid);
        }
        else
        {
            System.out.println("发卡失败");
        }
    }
    
    @Test
    public void testInsert1() {
        CardDAO cd=new CardDAO();
        try{
        if(cd.updateBalance("064532", 100))
        {
            System.out.println("存款成功");
        }else{
            System.out.println("存款失败");
        }
        }catch(Exception e){
            e.printStackTrace();
        }
    }

    @Test
    public void testInsert2() {
        CardDAO cd=new CardDAO();
        try{
        if(cd.login(" 123453' or 1=1--", "321312"))
        {
            System.out.println("");
        }
            
        
        }catch(Exception e){
            e.printStackTrace();
        }
    }
    @Test
    public void testInsert3() {
        CardDAO cd=new CardDAO();
        try{
        if(cd.login1("362569", "123456"))
        {
            System.out.println("登录成功");
        }else{
            System.out.println("登录失败");
        }
            
        
        }catch(Exception e){
            e.printStackTrace();
        }
    }
    //测试转账
    
    @Test
    public void testInsert4() {
        CardDAO cd=new CardDAO();
        try{
        if(cd.zhuanzhang("949806", "362569",5000))
        {
            System.out.println("转账成功");
        }else{
            System.out.println("转账失败");
        }
            
        
        }catch(Exception e){
            e.printStackTrace();
        }
    }
    
    //测试连接池
    @Test
    public void testInsert5() {
        CardDAO cd=new CardDAO();
        cd.testC3P0();
    }
    //测试连接池
    @Test
    public void testInsert6() {
        CardDAO cd=new CardDAO();
        cd.test1C3P0();
    }
    
    //测试获取卡信息
    @Test
    public void testInsert7() {
    
        CardDAO cd=new CardDAO();
        bank ba=cd.getcard("362569");
        System.out.println(ba);
    }
    
    //测试获取所有卡信息
        @Test
        public void testInsert8() {
        
            CardDAO cd=new CardDAO();
            List<bank> li=cd.getAll();
            for(bank ba:li)
            {
                System.out.println(ba);
            }
            
        }
}