Java基础学习记录之JDBC完成CRUD

这是JDBC进行单表的CRUD,为了减少代码的重复度，添加jdbcUtil工具类，完成Connection的获取和资源的释放。为了方便数据库相关的修改，添加jdbc.cfg.properties文件，

1.数据库：

create database basketball; use basketball; create table star( id int primary key auto_increment, name varchar(40), password varchar(40), email varchar(60), birthday date ); insert into users(name,password,email,birthday) values('James','LeBron','LeBron@sina.com','1984-12-30'); insert into users(name,password,email,birthday) values('Wede','Dwyane','Dwyane@sina.com','1982-1-17'); insert into users(name,password,email,birthday) values('Bosh','Chris','Chris@sina.com','1984-3-24'); insert into users(name,password,email,birthday) values('Bryant','Kobe','Kobe@sina.com','1978-08-23');

2.jdbc.cfg.properties:

root：是数据库的用户名，hello：是数据库的密码。

driverClass=com.mysql.jdbc.Driver url=jdbc:mysql:///basketball user=root password=hello3.jdbcUtil.java:

可以获取connection和释放资源。

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 { private static String driverClass; private static String url; private static String user; private static String password; static{ try { InputStream is = JdbcUtil.class.getClassLoader().getResourceAsStream("jdbc.cfg.properties"); Properties pro = new Properties(); pro.load(is); driverClass = pro.getProperty("driverClass"); url = pro.getProperty("url"); user = pro.getProperty("user"); password = pro.getProperty("password"); Class.forName(driverClass); } catch (Exception e) { throw new ExceptionInInitializerError(e); } } public static Connection getConnection() throws Exception{ Connection con = DriverManager.getConnection(url,user,password); return con; } public static void release(ResultSet rs,Statement stt,Connection con){ if(rs!=null){ try{ rs.close(); }catch(SQLException e){ e.printStackTrace(); } rs = null; } if(stt != null){ try{ stt.close(); }catch(SQLException e){ e.printStackTrace(); } stt = null; } if(con != null){ try{ con.close(); }catch(SQLException e){ e.printStackTrace(); } con = null; } } } 4.User.java：

import java.util.Date; public class User { private int id; private String name; private String password; private String email; private Date birthday; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getEmail() { return email; } public void setEmail(String email) { this.email = email; } public Date getBirthday() { return birthday; } public void setBirthday(Date birthday) { this.birthday = birthday; } @Override public String toString() { return "User [id=" + id + ", name=" + name + ", password=" + password + ", email=" + email + ", birthday=" + birthday + "]"; } } 5.CRUD：

测试时可以单独放开测试方法。

import java.sql.Connection; import java.sql.ResultSet; import java.sql.Statement; import test.domain.User; import test.jdbcUtil.JdbcUtil; public class JdbcCRUD { public static void main(String[] args) { // 添加 // testAdd(); // 修改 // testUpdate(); // 删除 // testDelete(); // 查找 // testFind(); } public static void testAdd(){ Connection con = null; Statement stt = null; ResultSet rs = null; try { con = JdbcUtil.getConnection(); stt = con.createStatement(); int num = stt.executeUpdate("insert into users(name,password,email,birthday) values('Irving','Kyrie','Kyrie@sina.com','1992-3-23')"); if(num != 0){ System.out.println("添加数据成功"); } } catch (Exception e) { throw new RuntimeException(e); }finally{ JdbcUtil.release(rs, stt, con); } } public static void testUpdate() { Connection con = null; Statement stt = null; ResultSet rs = null; try { con = JdbcUtil.getConnection(); stt = con.createStatement(); int num = stt.executeUpdate("update users set email='lakers@126.com' where id=4"); if(num != 0){ System.out.println("修改数据成功"); } } catch (Exception e) { throw new RuntimeException(); }finally{ JdbcUtil.release(rs, stt, con); } } public static void testDelete() { Connection con = null; Statement stt = null; ResultSet rs = null; try { con = JdbcUtil.getConnection(); stt = con.createStatement(); int num = stt.executeUpdate("delete from users where id = 2"); if(num != 0){ System.out.println("删除数据成功"); } } catch (Exception e) { throw new RuntimeException(); }finally{ JdbcUtil.release(rs, stt, con); } } public static void testFind() { Connection con = null; Statement stt = null; ResultSet rs = null; try { con = JdbcUtil.getConnection(); stt = con.createStatement(); rs = stt.executeQuery("select * from users"); if(rs.next()){ System.out.println(rs.getString("name")); } } catch (Exception e) { throw new RuntimeException(); }finally{ JdbcUtil.release(rs, stt, con); } } }