jdbk应用实例

首先要在数据库中建好表，表的属性要跟代码中的一致

使用jdbk连接数据库，并且进行增删改查的操作(curd).

package com.beiwi;

import java.sql.Connection;
import java.sql.DriverManager;
import java.util.ResourceBundle;

import java.sql.ResultSet;
import java.sql.Statement;

/**
 *    数据库的帮助类
 * @author Lrs
 *
 */
public class DBUtils {

    private static String driverClass;
    private static String url;
    private static String user;
    private static String password;
    
    
    static{
        ResourceBundle rb = ResourceBundle.getBundle("jdbc");
        driverClass = rb.getString("driverClass");
        url = rb.getString("url");
        user = rb.getString("user");
        password = rb.getString("password");
        
        try {
            Class.forName(driverClass);
        } catch (ClassNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
    
    public static Connection getConn() throws Exception{
        return DriverManager.getConnection(url, user, password);
    }
    
    public static void closeAll(ResultSet rs,Statement stmt,Connection conn){
        
        if(null!=rs){
            try {
                rs.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        if(null!=stmt){
            try {
                stmt.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        
        if(null!=conn){
            try {
                conn.close();
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    
}

package com.beiwi;

import java.sql.Connection;

import java.sql.ResultSet;
import java.sql.Statement;


/**
 * 增删改查操作的方法
 *  create:新增
 *  refer:查询
 *  update：更新
 *  delete：删除
 * @author Lrs
 *
 */
public class MasterCurd {

    
    /**
     * 查询所有主人的信息
     */
    public void findAll(){
        String sql = "SELECT * FROM master";
        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;
        
        try {
            conn = DBUtils.getConn();
            stmt = conn.createStatement();
            rs = stmt.executeQuery(sql);
            
            while (rs.next()) {
                System.out.println(rs.getObject(1));
                System.out.println(rs.getObject(2));
                System.out.println(rs.getObject(3));
                System.out.println(rs.getObject(4));
                System.out.println("**************************");
            }
        } catch (Exception e) {
            e.printStackTrace();
        }finally{
            DBUtils.closeAll(rs, stmt, conn);
        }
        
    }
    /**
     *  insert一条记录
     */
    
    public void insert(){
        String sql = "INSERT INTO master (id,user,password,money) VALUES ('4','haha','456','100');";
        
        Connection conn = null;
        Statement stmt = null;
        
        try {
            conn = DBUtils.getConn();
            stmt = conn.createStatement();
            stmt.executeUpdate(sql);
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            DBUtils.closeAll(null, stmt, conn);
        }
    }
    
    /**
     * 更新一条记录
     */
    public void update(){
        String sql = "UPDATE master SET user='beiwo1',password='456',money=888 WHERE id=1";
        Connection conn = null;
        Statement stmt = null;
        
        try {
            conn = DBUtils.getConn();
            stmt = conn.createStatement();
            int num = stmt.executeUpdate(sql);
            
            if (num>0) {
                System.out.println("更新成功");
            }
            
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            DBUtils.closeAll(null, stmt, conn);
        }
    }
    /**
     * 删除一条记录
     */
    public void delete(){
        String sql = "DELETE FROM master WHERE id=3";
        Connection  conn = null;
        Statement stmt = null;
        
        try {
            conn = DBUtils.getConn();
            stmt = conn.createStatement();
            int num = stmt.executeUpdate(sql);
            
            if (num > 0) {
                System.out.println("删除成功");
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            DBUtils.closeAll(null, stmt, conn);
        }
    }
}

package com.beiwi;

import org.junit.Before;
import org.junit.Test;

/**
 *  测试类
 */

public class TestMasterCrud {

    MasterCurd curd = null;
    
    @Before
    public void before(){
        curd = new MasterCurd();
    }
    @Test
    public void testFindAll(){
        curd.findAll();
    }
    @Test
    public void testInsert(){
        curd.insert();
    }
    @Test
    public void testUpdate(){
        curd.update();
    }
    @Test
    public void testDelete(){
        curd.delete();
    }
    @Test
    public void after(){
        curd=null;
    }
    
}