33、mybatis（二）

2022-04-28 02:53:37

第十六章回顾SQL99中的连接查询

1）内连接

2）外连接

3）自连接

第十七章回顾hibernate多表开发

1）一对一

2）一对多

3）多对多

第十八章 mybatis一对一映射【学生与身份证】

1）参见<<一对一图示.JPG>>

2）创建students.sql和cards.sql

drop table students;

drop table cards;

create table cards(

id int(5) primary key,

num varchar(20)

);

create table students(

id int(5) primary key,

name varchar(10),

cid int(5),

constraint cid_fk foreign key(cid) references cards(id)

);

insert into cards(id,num) values(1,'111');

insert into students(id,name,cid) values(1,'哈哈',1);

3）创建Students.java和Card.java

public class Card {

private Integer id;

private String num;

private Student student;

public Card(){}

public Integer getId() {

return id;

}

public void setId(Integer id) {

this.id = id;

}

public String getNum() {

return num;

}

public void setNum(String num) {

this.num = num;

}

public Student getStudent() {

return student;

}

public void setStudent(Student student) {

this.student = student;

}

public class Student {

private Integer id;

private String name;

private Card card;

public Student(){}

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 Card getCard() {

return card;

}

public void setCard(Card card) {

this.card = card;

}

4）创建StudentMapper.xml和CardMapper.xml

CardMapper.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">

</resultMap>

</mapper>

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">

</resultMap>

select s.id,s.name,c.id,c.num

from students s inner join cards c

on s.cid = c.id

and s.id = #{id}

</select>

</mapper>

5）创建StudentCardDao.java

public class StudentCardDao {

/**

* 查询1号【学生】

public Student findById(int id) throws Exception{

SqlSession sqlSession = null;

try{

sqlSession = MybatisUtil.getSqlSession();

return sqlSession.selectOne("studentNamespace.findById",id);

}catch(Exception e){

e.printStackTrace();

throw e;

}finally{

MybatisUtil.closeSqlSession();

}

public static void main(String[] args) throws Exception{

StudentCardDao dao = new StudentCardDao();

Student student = dao.findById(1);

System.out.println(student.getId()+":"+student.getName());

System.out.println(student.getCard().getId()+":"+student.getCard().getNum());

}

第十九章 mybatis一对多映射【班级与学生】

1）参见<<一对多图示.JPG>>

2）创建grades.sql和students.sql

drop table students;

drop table grades;

create table grades(

gid int(5) primary key,

gname varchar(10)

);

create table students(

sid int(5) primary key,

sname varchar(10),

sgid int(5),

constraint sgid_fk foreign key(sgid) references grades(gid)

);

insert into grades(gid,gname) values(1,'java');

insert into students(sid,sname,sgid) values(1,'哈哈',1);

insert into students(sid,sname,sgid) values(2,'呵呵',1);

3）创建Grade.java和Student.sql

/**

* 班级（单方）

* @author AdminTC

public class Grade {

private Integer id;

private String name;

private List<Student> studentList = new ArrayList<Student>();

public Grade(){}

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 List<Student> getStudentList() {

return studentList;

}

public void setStudentList(List<Student> studentList) {

this.studentList = studentList;

}

/**

* 学生（多方）

* @author AdminTC

public class Student {

private Integer id;

private String name;

private Grade grade;

public Student(){}

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 Grade getGrade() {

return grade;

}

public void setGrade(Grade grade) {

this.grade = grade;

}

4）创建GradeMapper.xml和StudentMapper.xml

GradeMapper.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">

</resultMap>

select g.gid,g.gname,s.sid,s.sname

from grades g,students s

where g.gid = s.sgid

and s.sname = #{name}

</select>

</mapper>

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">

</resultMap>

select s.sid,s.sname,g.gid,g.gname

from grades g,students s

where g.gid = s.sgid

and g.gname = #{name}

</select>

</mapper>

5）创建GradeStudentDao.java

public class GradeStudentDao {

/**

* 查询java班级有哪些【学生】

public List<Student> findAllByName(String name) throws Exception{

SqlSession sqlSession = null;

try{

sqlSession = MybatisUtil.getSqlSession();

return sqlSession.selectList("studentNamespace.findAllByName",name);

}catch(Exception e){

e.printStackTrace();

throw e;

}finally{

MybatisUtil.closeSqlSession();

}

/**

* 查询哈哈属于哪个【班级】

public Grade findGradeByName(String name) throws Exception{

SqlSession sqlSession = null;

try{

sqlSession = MybatisUtil.getSqlSession();

return sqlSession.selectOne("gradeNamespace.findGradeByName",name);

}catch(Exception e){

e.printStackTrace();

throw e;

}finally{

MybatisUtil.closeSqlSession();

}

public static void main(String[] args) throws Exception{

GradeStudentDao dao = new GradeStudentDao();

List<Student> studentList = dao.findAllByName("java");

for(Student s : studentList){

System.out.println(s.getId()+":"+s.getName()+":"+s.getGrade().getId()+":"+s.getGrade().getName());

}

Grade grade = dao.findGradeByName("哈哈");

System.out.println(grade.getId()+":"+grade.getName());

}

第二十章 mybatis多对多映射【学生与课程】

1）参见<<多对多图示.JPG>>

2）创建students.sql和courses.sql和middles.sql

drop table middles;

drop table students;

drop table courses;

create table students(

sid int(5) primary key,

sname varchar(10)

);

create table courses(

cid int(5) primary key,

cname varchar(10)

);

create table middles(

sid int(5),

cid int(5),

primary key(sid,cid)

);

insert into students(sid,sname) values(1,'哈哈');

insert into students(sid,sname) values(2,'呵呵');

insert into courses(cid,cname) values(1,'java');

insert into courses(cid,cname) values(2,'net');

insert into middles(sid,cid) values(1,1);

insert into middles(sid,cid) values(1,2);

insert into middles(sid,cid) values(2,1);

insert into middles(sid,cid) values(2,2);

select * from students;

select * from courses;

select * from middles;

3）创建Student.java和Course.java

/**

* 学生(多方)

* @author AdminTC

public class Student {

private Integer id;

private String name;

private List<Course> courseList = new ArrayList<Course>();

public Student(){}

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 List<Course> getCourseList() {

return courseList;

}

public void setCourseList(List<Course> courseList) {

this.courseList = courseList;

}

/**

* 课程(多方)

* @author AdminTC

public class Course {

private Integer id;

private String name;

private List<Student> studentList = new ArrayList<Student>();

public Course(){}

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 List<Student> getStudentList() {

return studentList;

}

public void setStudentList(List<Student> studentList) {

this.studentList = studentList;

}

4）创建StudentMapper.xml和CourseMapper.xml

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">

</resultMap>

select s.sid,s.sname

from students s,middles m,courses c

where s.sid = m.sid

and m.cid = c.cid

and c.cname = #{name}

</select>

</mapper>

CourseMapper.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">

</resultMap>

select c.cid,c.cname

from students s,middles m,courses c

where s.sid = m.sid

and m.cid = c.cid

and s.sname = #{name}

</select>

</mapper>

5）创建students.sql和courses.sql和middles.sql

public class StudentCourseDao {

/**

* 查询哈哈选学的【课程】

public List<Course> findCourseByName(String name) throws Exception{

SqlSession sqlSession = null;

try{

sqlSession = MybatisUtil.getSqlSession();

return sqlSession.selectList("courseNamespace.findCourseByName",name);

}catch(Exception e){

e.printStackTrace();

throw e;

}finally{

MybatisUtil.closeSqlSession();

}

/**

* 查询java课程有哪些【学生】

public List<Student> findStudentByName(String name) throws Exception{

SqlSession sqlSession = null;

try{

sqlSession = MybatisUtil.getSqlSession();

return sqlSession.selectList("studentNamespace.findStudentByName",name);

}catch(Exception e){

e.printStackTrace();

throw e;

}finally{

MybatisUtil.closeSqlSession();

}

public static void main(String[] args) throws Exception{

StudentCourseDao dao = new StudentCourseDao();

//List<Course> courseList = dao.findCourseByName("哈哈");

//for(Course c : courseList){

// System.out.println(c.getId()+":"+c.getName());

//}

List<Student> studentList = dao.findStudentByName("java");

for(Student s : studentList){

System.out.println(s.getId()+":"+s.getName());

}

第二十一章 spring + mybatis + mysql/oracle开发

1）创建一个spring-mybatis-mysql这么一个javaweb或java工程

2）导入spring-ioc，spring-aop，spring-transaction，mybatis，c3p0，mysql/oracle相关的jar包和spring整合mybatis的jar包

3）创建students.sql

--mysql

create table students(

sid int(5) primary key,

sname varchar(10),

ssal double(8,2)

);

4）创建Student.java

/**

* 学生

* @author AdminTC

public class Student {

private Integer id;//编号

private String name;//姓名

private Double sal;//薪水

public Student(){}

public Student(Integer id, String name, Double sal) {

this.id = id;

this.name = name;

this.sal = sal;

}

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 Double getSal() {

return sal;

}

public void setSal(Double sal) {

this.sal = sal;

}

5）创建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">

</resultMap>

insert into students(sid,sname,ssal) values(#{id},#{name},#{sal})

</insert>

</mapper>

6）创建StudentDao.java

public class StudentDao {

private SqlSessionFactory sqlSessionFactory;

public void setSqlSessionFactory(SqlSessionFactory sqlSessionFactory) {

this.sqlSessionFactory = sqlSessionFactory;

}

public void insert(Student student){

SqlSession sqlSession = sqlSessionFactory.openSession();

sqlSession.insert("studentNamespace.insert",student);

//int i = 10/0;

}

public static void main(String[] args) {

ApplicationContext ac = new ClassPathXmlApplicationContext(new String[]{"spring.xml"});

StudentDao studentDao = (StudentDao) ac.getBean("studentDaoID");

studentDao.insert(new Student(1,"哈哈",7000D));

}

7）在src目录下创建mybatis.xml

<?xml version="1.0" encoding="UTF-8"?>

<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"

"http://mybatis.org/dtd/mybatis-3-config.dtd">

</mappers>

</configuration>

8）在src目录下创建spring.xml

<?xml version="1.0" encoding="UTF-8"?>

<beans

xmlns="http://www.springframework.org/schema/beans"

xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

xmlns:context="http://www.springframework.org/schema/context"

xmlns:aop="http://www.springframework.org/schema/aop"

xmlns:tx="http://www.springframework.org/schema/tx"

xmlns:mvc="http://www.springframework.org/schema/mvc"

xsi:schemaLocation="

http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans-3.0.xsd

http://www.springframework.org/schema/context

http://www.springframework.org/schema/context/spring-context-3.0.xsd

http://www.springframework.org/schema/aop

http://www.springframework.org/schema/aop/spring-aop-3.0.xsd

http://www.springframework.org/schema/tx

http://www.springframework.org/schema/tx/spring-tx-3.0.xsd

http://www.springframework.org/schema/mvc

http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd

</bean>

</bean>

</bean>

<tx:advice id="tx" transaction-manager="dataSourceTransactionManagerID">

<tx:attributes>

<tx:method name="*" propagation="REQUIRED"/>

</tx:attributes>

</tx:advice>

<aop:config>

<aop:pointcut id="pointcut" expression="execution(* cn.itcast.javaee.mybatis.dao.*.*(..))"/>

<aop:advisor advice-ref="tx" pointcut-ref="pointcut" />

</aop:config>

</bean>

</beans>

第二十二章 jsp/js/jquery/easyui/json + @springmvc + spring + mybatis + mysql/oracle开发

1）员工管理系统--增加员工

第二十三章 jdbc访问oracle存储过程和存储函数

1）写一个计算个人所得税的应用

--定义过程

create or replace procedure get_rax(salary in number,rax out number)

--需要交税的钱

bal number;

begin

bal := salary - 3500;

if bal<=1500 then

rax := bal * 0.03 - 0;

elsif bal<=4500 then

rax := bal * 0.1 - 105;

elsif bal<=9000 then

rax := bal * 0.2 - 555;

elsif bal<=35000 then

rax := bal * 0.25 - 1005;

elsif bal<=55000 then

rax := bal * 0.3 - 2755;

elsif bal<=80000 then

rax := bal * 0.35 - 5505;

else

rax := bal * 0.45 - 13505;

end if;

end;

--调用过程

declare

--交税

rax number;

salary number := &salary;

begin

get_rax(salary,rax);

dbms_output.put_line(salary||'元工资需要交'||rax||'元税');

end;

//Java调用过程

public class TestCallOracleProc {

public static void main(String[] args) throws Exception{

String sql = "{call get_rax(?,?)}";

Connection conn = JdbcUtil.getConnection();

CallableStatement cstmt = conn.prepareCall(sql);

cstmt.setInt(1,10000);

cstmt.registerOutParameter(2,Types.INTEGER);

cstmt.execute();

Integer rax = cstmt.getInt(2);

System.out.println("10000元需要交" + rax + "元税");

JdbcUtil.close(cstmt);

JdbcUtil.close(conn);

}

查询7788号员工的的姓名，职位，月薪

--定义函数

create or replace function findEmpNameAndJobAndSal(pempno in number,pjob out varchar2,psal out number)

return varchar2

pename emp.ename%type;

begin

select ename,job,sal into pename,pjob,psal from emp where empno = pempno;

return pename;

end;

--调用函数

declare

pename emp.ename%type;

pjob emp.job%type;

psal emp.sal%type;

begin

pename := findEmpNameAndJobAndSal(7788,pjob,psal);

dbms_output.put_line('7788'||'--'||pename||'--'||pjob||'--'||psal);

end;

//Java调用函数

public class TestCallOracleFunc {

public static void main(String[] args) throws Exception{

String sql = "{?=call findEmpNameAndJobAndSal(?,?,?)}";

Connection conn = JdbcUtil.getConnection();

CallableStatement cstmt = conn.prepareCall(sql);

cstmt.registerOutParameter(1,Types.VARCHAR);

cstmt.setInt(2,7788);

cstmt.registerOutParameter(3,Types.VARCHAR);

cstmt.registerOutParameter(4,Types.INTEGER);

cstmt.execute();

String ename = cstmt.getString(1);

String job = cstmt.getString(3);

Integer sal = cstmt.getInt(4);

System.out.println(ename+":"+job+":"+sal);

JdbcUtil.close(cstmt);

JdbcUtil.close(conn);

}

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