Student
package domain;
import java.sql.Date;
public class Student {
private Integer id;
private String name;
private Integer sex;
private Integer birth;
private Date ctime;
@Override
public String toString() {
return "Student{" +
"id=" + id +
", name='" + name + '\'' +
", sex=" + sex +
", birth=" + birth +
", ctime=" + ctime +
'}';
}
public Student() {
}
public Student(Integer id, String name, Integer sex, Integer birth, Date ctime) {
this.id = id;
this.name = name;
this.sex = sex;
this.birth = birth;
this.ctime = ctime;
}
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 Integer getSex() {
return sex;
}
public void setSex(Integer sex) {
this.sex = sex;
}
public Integer getBirth() {
return birth;
}
public void setBirth(Integer birth) {
this.birth = birth;
}
public Date getCtime() {
return ctime;
}
public void setCtime(Date ctime) {
this.ctime = ctime;
}
}
StudentDao
package dao;
import domain.Student;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import java.io.InputStream;
import java.util.List;
import java.util.Map;
@SuppressWarnings("all")
public class StudentDao {
//设计一个方法 根据sex分组 每一个组中的人数
public List<Map<String,Object>> selectCountBySex(){
SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
SqlSessionFactory factory = builder.build(Thread.currentThread().getContextClassLoader().getResourceAsStream("configuration.xml"));
SqlSession sqlSession = factory.openSession(true);
List<Map<String,Object>> result = sqlSession.selectList("selectCountBySex");
return result;
}
//设计一个方法 根据编号查询对应的人名
public String selectNameById(){//缺少一个参数id
SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
SqlSessionFactory factory = builder.build(Thread.currentThread().getContextClassLoader().getResourceAsStream("configuration.xml"));
SqlSession sqlSession = factory.openSession(true);
String name = sqlSession.selectOne("selectNameById");
return name;
}
//设计一个方法 查询表格中记录的个数
public int selectCount(){
SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
SqlSessionFactory factory = builder.build(Thread.currentThread().getContextClassLoader().getResourceAsStream("configuration.xml"));
SqlSession sqlSession = factory.openSession(true);
int ct = sqlSession.selectOne("selectCount");
return ct;
}
//设计一个方法 查询表格中的全部内容
public List<Student> selectAll(){
SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
SqlSessionFactory factory = builder.build(Thread.currentThread().getContextClassLoader().getResourceAsStream("configuration.xml"));
SqlSession sqlSession = factory.openSession(true);
List<Student> studentList = sqlSession.selectList("selectAll");//SQL语句的id SQL上面的问号信息 告知每一行记录存储的类型
return studentList;
}
//设计一个方法 查询单条记录 读操作 携带返回值
public Student selectOne() {//应该需要参数 先固定
//JDBC+SQL 告知SQL 告知SQL上面的问号信息(可以有 可以没有) 告知容器(一行记录)类型
//加载驱动
//获取连接
//状态参数 conn.prepareStatement(sql);
//将SQL和问号信息拼接完整
//执行操作 ResultSet = executeQuery();
//结果集中查询出来的信息 取出来存在一个新的容器内(数组 List Set Map domain) 结果集关掉啦
//关闭操作 rs.close() pstat.close() conn.close();
//返回那个新的容器
//找寻sqlSession对象就可以啦
SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
InputStream inputStream = Thread.currentThread().getContextClassLoader().getResourceAsStream("configuration.xml");
//InputStream inputStream = Resources.getResourceAsStream("configuration.xml");
//下面第二种方式获取输入流 几个点需要大家注意
// 1.Resources这个类是MyBatis框架提供 依赖度比较高
// 2.方法与之前我们利用ClassLoader加载的方法名一致 框架提供的方法有异常必须处理
SqlSessionFactory factory = builder.build(inputStream);
SqlSession sqlSession = factory.openSession(true);
//让sqlSession帮我们做事
Student student = sqlSession.selectOne("selectOne");//1.SQL语句的id SQL语句上面的问号信息(暂时没有) 查询完毕的结果装到什么容器里
return student;
}
//设计一个方法 新增一条学生记录
public void insert(){
//JDBC流程----不需要我们写啦
//MyBatis帮我们做操作
//创建工人对象
SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();
InputStream inputStream = Thread.currentThread().getContextClassLoader().getResourceAsStream("configuration.xml");
//获取工厂对象
SqlSessionFactory factory = builder.build(inputStream);//图纸 核心配置文件
//获取提供的那个对象SqlSession
SqlSession sqlSession = factory.openSession(true);//自动开启事务 自动提交 默认false 自动开启事务 不提交
//帮我们执行数据库操作 增删改
sqlSession.insert("insert");//加载驱动 获取连接(连接池) 创建状态参数
//sqlSession.commit();
}
}
StudentMapper.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="dao.StudentDao">
<insert id="insert">
insert into student values(10,'zzt',1,1993,'2019-10-24')
</insert>
<select id="selectOne" resultType="domain.Student">
select * from student where id = 1
</select>
<select id="selectAll" resultType="domain.Student">
select * from student
</select>
<select id="selectCount" resultType="int">
select count(*) as ct from student <--语句不用带;号-->
</select>
<select id="selectNameById" resultType="string"> <--这里运用了别名-->
select name from student where id = 1;
</select>
<select id="selectCountBySex" resultType="hashmap">
select sex,count(*) as ct from student group by sex
</select>
</mapper>
TestMain
public class TestMain {
public static void main(String[] args) {
StudentDao dao = new StudentDao();
//dao.insert();
// Student student = dao.selectOne();
// System.out.println(student);
// List<Student> studentList = dao.selectAll();
// for(Student student : studentList){
// System.out.println(student);
// }
// int count = dao.selectCount();
// System.out.println(count);
// String name = dao.selectNameById();
// System.out.println(name);
List<Map<String,Object>> result = dao.selectCountBySex();
for(Map<String,Object> map : result){
System.out.println(map);
}
}
}
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