java入门作业-Mybatis框架
MyBatis 是支持普通 SQL查询，存储过程和高级映射的优秀持久层框架。本节用mybatis来替代JDBC的功能。
材料是jc0122.sql，里面的admin_info是要操作的表。不像上一节需要把数据库文件放到java目录里。数据库只要在本地即可。本节要实现对数据库的查询+添加。
需要导入包，下载可去官网 mybatis – MyBatis 3 | 入门
本次作业存放位置：注意最后两个在src目录下，不在S5包内
一、配置文件
创建mybatis-config.xml，里面粘贴上官网上的配置代码，自己改改
注意绑定的数据库，我一开始只有jc0122会报错，加上后面这些字符就好了。用户名和密码也设置成自己的，mapper一开始没写的话就注释pass掉
再新建config.properties，里面放上类似上面的四项数据，方便后面调用
url=jdbc:mysql://localhost:3306/jc0122
driver=com.mysql.cj.jdbc.Driver
name=root
pwd=123456二、 Util包-链接数据库
创建DBUtil，写链接数据库的方法。会调用到上面提到的config.properties
package S5.util;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.Properties;
public class DBUtil {
private static Properties pro = new Properties();
private static String url;
private static String driver;
private static String name;
private static String pwd;
static {
InputStream ins = DBUtil.class.getClassLoader().getResourceAsStream("config.properties");
try {
pro.load(ins);
url = pro.getProperty("url");
driver = pro.getProperty("driver");
name = pro.getProperty("name");
pwd = pro.getProperty("pwd");
} catch (IOException e) {
e.printStackTrace();
}
}
public static Connection getCone() {
try {
Class.forName(driver);
Connection cone = DriverManager.getConnection(url,name,pwd);
return cone;
} catch (ClassNotFoundException e) {
e.printStackTrace();
} catch (SQLException e) {
e.printStackTrace();
}
return null;
}
// 关闭的方法
public static void close(Connection cone) {
try {
if (cone != null) {
cone.close();
}
} catch (SQLException e) {
e.printStackTrace();
}
}
}三、pojo包-声明变量getset
确定类型直接生成，最终要字符串输出
package S5.pojo;
import java.util.Date;
public class AdminInfo {
private Integer adminId ;
private String adminName;
private String adminPwd;
private Integer roleId;
private Integer adminState;
private Date adminCtime;
private Date adminMtime;
public AdminInfo() {
}
public Integer getAdminId() {
return adminId;
}
public void setAdminId(Integer adminId) {
this.adminId = adminId;
}
public String getAdminName() {
return adminName;
}
public void setAdminName(String adminName) {
this.adminName = adminName;
}
public String getAdminPwd() {
return adminPwd;
}
public void setAdminPwd(String adminPwd) {
this.adminPwd = adminPwd;
}
public Integer getRoleId() {
return roleId;
}
public void setRoleId(Integer roleId) {
this.roleId = roleId;
}
public Integer getAdminState() {
return adminState;
}
public void setAdminState(Integer adminState) {
this.adminState = adminState;
}
public Date getAdminCtime() {
return adminCtime;
}
public void setAdminCtime(Date adminCtime) {
this.adminCtime = adminCtime;
}
public Date getAdminMtime() {
return adminMtime;
}
public void setAdminMtime(Date adminMtime) {
this.adminMtime = adminMtime;
}
@Override
public String toString() {
return "AdminInfo{" +
"adminId=" + adminId +
", adminName='" + adminName + '\'' +
", adminPwd='" + adminPwd + '\'' +
", roleId=" + roleId +
", adminState=" + adminState +
", adminCtime=" + adminCtime +
", adminMtime=" + adminMtime +
'}';
}
}
四、DAO包
先创建一个接口类AdminDao，要导入上面的AdminInfo，声明两个方法，分别是账号密码查询和分页查询
package S5.dao;
import S5.pojo.AdminInfo;
import java.util.List;
public interface AdminDao {
/**
* 通过账号密码查询admin对象
* @param name 账号
* @param pwd 密码
* @return admin 对象
*/
AdminInfo selectByNameAndPwd(String name, String pwd);
/**
* 分页查询用户信息
* @param start 起始
* @param limit 条数
* @return admin对象集合
*/
List selectByPage(Integer start, Integer limit);
}
再创建AdminDaolmpl，实现查询，会调用到DBUtil。变量名大写。
package S5.dao;
import S5.pojo.AdminInfo;
import S5.util.DBUtil;
import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
public class AdminDaoImpl implements AdminDao {
@Override
public AdminInfo selectByNameAndPwd(String name, String pwd) {
//获取sql连接
Connection conn = DBUtil.getCone();
String sql = "SELECT * FROM ADMIN_INFO WHERE ADMIN_NAME = ? AND ADMIN_PWD = ?";
try {
PreparedStatement ps = conn.prepareStatement(sql);
ps.setObject(1,name);
ps.setObject(2,pwd);
ResultSet set = ps.executeQuery();
if (set.next()){
AdminInfo adminInfo = new AdminInfo();
adminInfo.setAdminId(set.getInt("ADMIN_ID"));
adminInfo.setAdminName(set.getString("ADMIN_NAME"));
adminInfo.setAdminPwd(set.getString("ADMIN_PWD"));
adminInfo.setAdminCtime(set.getDate("ADMIN_CTIME"));
adminInfo.setAdminMtime(set.getDate("ADMIN_MTIME"));
adminInfo.setAdminState(set.getInt("ADMIN_STATE"));
adminInfo.setRoleId(set.getInt("ROLE_ID"));
return adminInfo;
}
} catch (SQLException e) {
e.printStackTrace();
}finally {
DBUtil.close(conn);
}
return null;
}
/**
* 分页查询用户信息
*
* @param start 起始
* @param limit 条数
* @return admin对象集合
*/
@Override
public List selectByPage(Integer start, Integer limit) {
//获取sql连接
Connection conn = DBUtil.getCone();
String sql = "SELECT * FROM ADMIN_INFO LIMIT ? , ?";
try {
PreparedStatement ps = conn.prepareStatement(sql);
ps.setObject(1,start);
ps.setObject(2,limit);
ResultSet set = ps.executeQuery();
List list = new ArrayList<>();
while (set.next()){
AdminInfo adminInfo = new AdminInfo();
adminInfo.setAdminId(set.getInt("ADMIN_ID"));
adminInfo.setAdminName(set.getString("ADMIN_NAME"));
adminInfo.setAdminPwd(set.getString("ADMIN_PWD"));
adminInfo.setAdminCtime(set.getDate("ADMIN_CTIME"));
adminInfo.setAdminMtime(set.getDate("ADMIN_MTIME"));
adminInfo.setAdminState(set.getInt("ADMIN_STATE"));
adminInfo.setRoleId(set.getInt("ROLE_ID"));
list.add(adminInfo);
}
return list;
} catch (SQLException e) {
e.printStackTrace();
}finally {
DBUtil.close(conn);
}
return null;
}
}
五、封装成DAO工厂
方便调用
package S5.factory;
import S5.dao.AdminDao;
import S5.dao.AdminDaoImpl;
public class DaoFactory {
public static AdminDao getAdminDAO() {
return new AdminDaoImpl();
}
}
六、mapper
创建一个包mapper，新建一个接口 命名规则 pojo+Mapper
package S5.mapper;
import org.apache.ibatis.annotations.Param;
import S5.pojo.AdminInfo;
import java.util.List;
public interface AdminInfoMapper {
List selectAll();
Integer insertOne(@Param("a") AdminInfo adminInfo);
/**
* 根据idx修改名字
* @param adminName
* @param id
* @return
*/
Integer updateById(@Param("name") String adminName, @Param("id") Integer id);
Integer deleteById(@Param("id") Integer id);
/**
* 分页并按条件查询
* @param adminName 姓名
* @param bdata 注册开始时间
* @param edate 注册的结束时间
* @param rid 角色查询
* @param start 分页开始
* @param limit 分页条数
* @return
*/
List selectByPage(@Param("name") String adminName, @Param("bdata") String bdata,
@Param("edate") String edate, @Param("rid") Integer rid,
@Param("start") Integer start, @Param("limit") Integer limit);
}
继续在这个mapper 包下创建一个AdminInfoMapper.xml
insert into admin_info(admin_id, admin_name, admin_pwd, admin_state, admin_ctime, role_id)
values(null,#{a.adminName},#{a.adminPwd},1,now(),#{a.roleId})
注意配置要和自己的一致，并且mybatis-config.xml可以不注释mapper这行了
七、测试
demo中测试
import S5.factory.DaoFactory;
import S5.mapper.AdminInfoMapper;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import S5.pojo.AdminInfo;
import S5.util.DBUtil;
import java.io.IOException;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.DriverManager;
import java.util.List;
public class Demo {
public static void main(String[] args) throws IOException {
// System.out.println("DBUtil:" + DBUtil.getCone());
//
// AdminInfo adminInfo = DaoFactory.getAdminDAO().selectByNameAndPwd("zhangsan","123456");
// System.out.println(adminInfo);
//
// List list = DaoFactory.getAdminDAO().selectByPage(0,3);
// System.out.println(list);
String resource = "mybatis-config.xml"; //读取配置文件的目录
InputStream inputStream = Resources.getResourceAsStream(resource); //加载配置文件
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); //从配置文件中获取sqlsession 连接的工厂类
SqlSession sqlSession = sqlSessionFactory.openSession(); //获取sql语句的操作对象 SQLsession
System.out.println(sqlSession);
AdminInfoMapper adminInfoMapper = sqlSession.getMapper(AdminInfoMapper.class); // 由SQL工厂来管理mapper（dao）
List list = adminInfoMapper.selectAll();
System.out.println(list);
AdminInfo adminInfo = new AdminInfo();
adminInfo.setAdminName("班班");
adminInfo.setAdminPwd("123456");
adminInfo.setRoleId(1);
adminInfoMapper.insertOne(adminInfo);
// 数据库中增删改是需要提交的 commit ,平时的数据库的软件默认自动提交的，但是代码中需要手动提交
sqlSession.commit();//提交到数据库
List list2 = adminInfoMapper.selectAll();
System.out.println(list2);
}
}
第一行是原先数据列出，第二行是添加后的所有
navicat上也可以查到。（左下角刷新）