2、分层实现：
cn.csdn.web.util 封装单利模式的Connction对象
cn.csdn.web.domain 封装实体bean
cn.csdn.web.dao 封装接口与接口实现类
cn.csdn.web.junit 测试类
首先利用单利模式创建Connection对象 （一定要记得在lib文件夹中放入驱动jar包）
cn.csdn.web.util 封装单利模式的Connction对象
package cn.csdn.web.Util;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
public class JdbcUtil {
//定义数据库URL语句
private static final String url = "jdbc:
mysql://localhost:3306/3g user=root&password=211314&useUnicode=true&characterEncoding=UTF8";
//利用单利模式创建Connction对象
private static Connection conn = null;
//加载驱动
public static Connection getConn(){
if(conn==null){
try {
Class.forName("com.mysql.jdbc.Driver");
conn = DriverManager.getConnection(url);
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
return conn;
}
//释放资源方法
public static void release(ResultSet rs,PreparedStatement pstmt){
if(rs!=null){
try {
rs.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
if(pstmt!=null){
try {
pstmt.close();
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
}
在domain层中封装实体bean
cn.csdn.web.util 封装单利模式的Connction对象
package cn.csdn.web.domain;
public class Users {
private Integer id;
private String name;
private String pass;
private String sex;
private Integer age;
public Users() {
super();
// TODO Auto-generated constructor stub
}
public Users(Integer id, String name, String pass, String sex, Integer age) {
super();
this.id = id;
this.name = name;
this.pass = pass;
this.sex = sex;
this.age = age;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getPass() {
return pass;
}
public void setPass(String pass) {
this.pass = pass;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
@Override
public String toString() {
return "Users [id=" + id + ", name=" + name + ", pass=" + pass
+ ", sex=" + sex + ", age=" + age + "]";
}
}
domain层中封装操作接口与接口实现类
package cn.csdn.web.dao;
import cn.csdn.web.domain.Users;
public interface UsersDao {
boolean insert(Users entity);//增
boolean deleteById(Integer id);//删
boolean updateById(Users entity);//改
Users findById(Integer id);//查
}
cn.csdn.web.util 封装单利模式的Connction对象
package cn.csdn.web.dao;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;