MyBatis初学

MyBatis 初学笔记

Student.java

package com.xiejiaohui.domain;

import java.util.Date;

public class Student {

private Integer studId;
private String name;
private String email;
private Date dob;

public Integer getStudId() {
return studId;
}
public void setStudId(Integer studId) {
this.studId = studId;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getEmail() {
return email;
}
public void setEmail(String email) {
this.email = email;
}
public Date getDob() {
return dob;
}
public void setDob(Date dob) {
this.dob = dob;
}
}

StudentMapper.java

package com.xiejiaohui.mappers;

import java.util.List;

import org.apache.ibatis.session.RowBounds;

import com.xiejiaohui.domain.Student;

public interface StudentMapper {

List<Student> findAllStudents();

List<Student> findAllStudents(RowBounds rowBounds);

Student findStudentById(Integer id);

void insertStudent(Student student);

int deleteAllStudents();

int countAllStudents();

}

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="com.xiejiaohui.mappers.StudentMapper">

<resultMap type="Student" id="StudentResult">
<id property="studId" column="stud_id"/>
<result property="name" column="name"/>
<result property="email" column="email"/>
<result property="dob" column="dob"/>
</resultMap>

<select id="findAllStudents" resultMap="StudentResult">
select * from students
</select>

<select id="findStudentById" parameterType="int" resultType="Student">
select stud_id as studid, name, email, dob
from students where stud_id=#{Id}
</select>

<insert id="insertStudent" parameterType="Student">
insert into students(stud_id, name, email, dob)
values(#{studId }, #{name}, #{email}, #{dob})
</insert>

<delete id="deleteAllStudents" parameterType="int">
delete from students
</delete>

<select id="countAllStudents" resultType="int">
select count(*) from students
</select>

</mapper>

StudentService.java

package com.xiejiaohui.services;

import java.util.List;

import org.apache.ibatis.session.RowBounds;
import org.apache.ibatis.session.SqlSession;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.xiejiaohui.domain.Student;
import com.xiejiaohui.mappers.StudentMapper;
import com.xiejiaohui.util.MyBatisSqlSessionFactory;

public class StudentService {

private Logger logger = LoggerFactory.getLogger(getClass());

public List<Student> findAllStudents() {
SqlSession sqlSession = MyBatisSqlSessionFactory.openSession();
try {
StudentMapper studentMapper = sqlSession.getMapper(StudentMapper.class);
return studentMapper.findAllStudents();
} finally {
sqlSession.close();
}
}

/**
* 采用分页的方式来查询
*/
public List<Student> findAllStudents2() {
int offset = 0, limit = 10;
RowBounds rowBounds = new RowBounds(offset, limit);
SqlSession sqlSession = MyBatisSqlSessionFactory.openSession();
try {
StudentMapper studentMapper = sqlSession.getMapper(StudentMapper.class);
return studentMapper.findAllStudents(rowBounds);
} finally {
sqlSession.close();
}
}

public Student findStudentById(Integer studId) {
logger.debug("Select Student By ID: {}", studId);
SqlSession sqlSession = MyBatisSqlSessionFactory.openSession();
try {
StudentMapper studentMapper = sqlSession.getMapper(StudentMapper.class);
return studentMapper.findStudentById(studId);
} finally {
sqlSession.close();
}
}

public Student findStudentById2(Integer studId) {
SqlSession sqlSession = MyBatisSqlSessionFactory.openSession();
try {
Student student = (Student) sqlSession.selectOne("com.xiejiaohui.mappers.StudentMapper.findStudentById",
studId);
return student;
} finally {
sqlSession.close();
}
}

public void createStudent(Student student) {
SqlSession sqlSession = MyBatisSqlSessionFactory.openSession();
try {
StudentMapper studentMapper = sqlSession.getMapper(StudentMapper.class);
studentMapper.insertStudent(student);
sqlSession.commit();
} finally {
sqlSession.close();
}
}

public int deleteAllStudents() {
SqlSession sqlSession = MyBatisSqlSessionFactory.openSession();
try {
StudentMapper studentMapper = sqlSession.getMapper(StudentMapper.class);
int i = studentMapper.deleteAllStudents();
sqlSession.commit();
return i;
} finally {
sqlSession.close();
}
}

public int countAllStudents() {
SqlSession sqlSession = MyBatisSqlSessionFactory.openSession();
try {
StudentMapper studentMapper = sqlSession.getMapper(StudentMapper.class);
int i = studentMapper.countAllStudents();
return i;
} finally {
sqlSession.close();
}
}

}

StudentServiceTest.java

package com.xiejiaohui.services;

import java.util.Date;
import java.util.List;

import org.junit.AfterClass;
import org.junit.Assert;
import org.junit.BeforeClass;
import org.junit.Test;

import com.xiejiaohui.domain.Student;

public class StudentServiceTest {

private static StudentService studentService;

@BeforeClass
public static void setup() {
studentService = new StudentService();
}

@AfterClass
public static void teardown() {
studentService = null;
}

@Test
public void testCreateStudent() {
for (int i = 1; i <= 100; i++) {
Student student = new Student();
int id = i;
student.setStudId(id);
student.setName("student_" + id);
student.setEmail("student_" + id + "@gmail.com");
student.setDob(new Date());
studentService.createStudent(student);
Student newStudent = studentService.findStudentById(id);
Assert.assertNotNull(newStudent);
}
}

@Test
public void testFindAllStudents() {
List<Student> students = studentService.findAllStudents();
Assert.assertNotNull(students);
for (Student student : students) {
System.out.println(student);
}
}

@Test
public void testFindAllStudents2() {
List<Student> students = studentService.findAllStudents2();
Assert.assertNotNull(students);
for (Student student : students) {
System.out.println("......" + student.getName());
}
}

@Test
public void testFindStudentById() {
Student student = studentService.findStudentById(1);
Assert.assertNotNull(student);
System.out.println(student);
}

@Test
public void testFindStudentById2() {
Student student = studentService.findStudentById2(1);
Assert.assertNotNull(student);
System.out.println(student);
}

@Test
public void testDeleteAllStudents() {
int begin = studentService.countAllStudents();
int end = studentService.deleteAllStudents();
Assert.assertEquals(end, begin);
System.out.println("begin: " + begin + " end: " + end);
}

//	create table students(stud_id int(11) not null auto_increment, name varch
//			ar(50) not null, email varchar(50) not null, dob date default null, primary key
//			(stud_id));

}

MyBatisSqlSessionFactory.java

package com.xiejiaohui.util;

import java.io.IOException;
import java.io.InputStream;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;

public class MyBatisSqlSessionFactory {

private static SqlSessionFactory sqlSessionFactory;

public static SqlSessionFactory getSqlSessionFactory() {
if (sqlSessionFactory == null) {
InputStream inputStream;
try {
inputStream = Resources.getResourceAsStream("mybatis-config.xml");
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
} catch (IOException e) {
throw new RuntimeException(e.getCause());
}
}
return sqlSessionFactory;
}

public static SqlSession openSession() {
return getSqlSessionFactory().openSession();
}
}

MyBatisUtil.java

package com.xiejiaohui.util;

import org.apache.ibatis.session.SqlSession;

public class MyBatisUtil {

public static SqlSession openSession() {

return MyBatisSqlSessionFactory.openSession();

}

}

log4j.properties

log4j.rootLogger=DEBUG, stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d [%-5p] %c - %m%n

mybatis-config.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">
<configuration>
<typeAliases>
<typeAlias alias="Student" type="com.xiejiaohui.domain.Student"/></typeAliases>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/test"/>
<property name="username" value="root"/>
<property name="password" value="123456abcd"/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="com/xiejiaohui/mappers/StudentMapper.xml"/>
</mappers>
</configuration>

需要引入的包 pom.xml

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd"> 
<modelVersion>4.0.0</modelVersion>
<groupId>com.xiejiaohui.study_mybatis</groupId>
<artifactId>study_mybatis</artifactId>
<version>1.0</version>
<name>Study MyBatis</name>

<dependencies>

<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.2.2</version>
</dependency>

<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.22</version>
<scope>runtime</scope>
</dependency>

<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.5</version>
</dependency>

<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-log4j12</artifactId>
<version>1.7.5</version>
<scope>runtime</scope>
</dependency>

<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
<scope>runtime</scope>
</dependency>

<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.11</version>
<scope>test</scope>
</dependency>

</dependencies>

数据库建表语句

create table students(stud_id int(11) not null auto_increment, name varch
ar(50) not null, email varchar(50) not null, dob date default null, primary key
(stud_id));