mybatis Entry _ Power node Java College Collation
- 2020-10-31 21:45:16
- OfStack
This article shares mybatis introduction learning materials for your reference, the specific content is as follows
Other tools or techniques needed:
Project management tool: Maven
Test run tool: Junit
Database: Derby
Without further ado, direct code
Maven Dependencies:
<dependencies>
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.2.7</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.9</version>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.apache.derby</groupId>
<artifactId>derby</artifactId>
<version>10.10.2.0</version>
</dependency>
<dependency>
<groupId>org.apache.derby</groupId>
<artifactId>derbyclient</artifactId>
<version>10.10.2.0</version>
</dependency>
</dependencies>
SQL Table building and data insertion:
CREATE TABLE USER_TEST_TB(
ID INT PRIMARY KEY,
USERNAME VARCHAR(20) NOT NULL,
PASSWORD VARCHAR(20) NOT NULL,
NICKNAME VARCHAR(20) NOT NULL
);
INSERT INTO USER_TEST_TB VALUES(1,'1st','111','Jack');
INSERT INTO USER_TEST_TB VALUES(2,'2nd','222','Rose');
INSERT INTO USER_TEST_TB VALUES(3,'3rd','333','Will');
Mybatis profile src/main/resource source directory
test-mybatis-configuration.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>
<properties>
<property name="driver" value="org.apache.derby.jdbc.ClientDriver" />
<property name="url"
value="jdbc:derby://localhost:1527/freud;create=true" />
</properties>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC" />
<dataSource type="POOLED">
<property name="driver" value="${driver}" />
<property name="url" value="${url}" />
</dataSource>
</environment>
</environments>
<mappers>
<!-- <mapper class="com.freud.practice.UserMapper" /> -->
<mapper resource="com/freud/practice/UserMapper.xml" />
</mappers>
</configuration>
UserMapper. xml Mapper file (src/main/java/com. freud. practice directory)
<?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.freud.practice.UserMapper">
<select id="getUser" resultType="com.freud.practice.User">
select *
from USER_TEST_TB
</select>
</mapper>
User. Java object classes (src/main/java/com. freud. practice directory)
package com.freud.practice;
public class User
{
private Integer id;
private String username;
private String password;
private String nickname;
public Integer getId()
{
return id;
}
public void setId(Integer id)
{
this.id = id;
}
public String getUsername()
{
return username;
}
public void setUsername(String username)
{
this.username = username;
}
public String getPassword()
{
return password;
}
public void setPassword(String password)
{
this.password = password;
}
public String getNickname()
{
return nickname;
}
public void setNickname(String nickname)
{
this.nickname = nickname;
}
}
UserMapper. java Mapper class (src/main/java/com. freud. practice directory)
package com.freud.practice;
import java.util.List;
import org.apache.ibatis.annotations.Select;
public interface UserMapper
{
//@Select("SELECT * FROM USER_TEST_TB")
public List<User> getUser();
}
The test class TestMyBatis. java (src/test/java/com. freud. practice directory)
package com.freud.practice;
import java.io.InputStream;
import java.text.MessageFormat;
import java.util.List;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Before;
import org.junit.Test;
public class TestMyBatis
{
private String source;
private InputStream inputStream;
private SqlSessionFactory sqlSessionFactory;
@Before
public void setUp()
{
source = "test-mybatis-configuration.xml";
}
@Test
public void testXMLConfingureSessionFactory()
{
try
{
inputStream = TestMyBatis.class.getClassLoader().getResourceAsStream(source);
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession session = sqlSessionFactory.openSession();
List<User> users = (List) session.selectList("com.freud.practice.UserMapper.getUser");
System.out.println("Query by XML configuration...");
this.printUsers(users);
UserMapper userMapper = session.getMapper(UserMapper.class);
System.out.println("\r\nQuery by annotation configuration...");
this.printUsers(userMapper.getUser());
}
catch (Exception e)
{
e.printStackTrace();
}
}
private void printUsers(final List<User> users)
{
int count = 0;
for (User user : users)
{
System.out.println(MessageFormat.format("==User[{0}]=================", ++count));
System.out.println("User Id: " + user.getId());
System.out.println("User UserName: " + user.getUsername());
System.out.println("User Password: " + user.getPassword());
System.out.println("User nickname: " + user.getNickname());
}
}
}
The above is a good introduction to using XML as the Mapper configuration file. In fact, Mybatis also supports Annotation. The details are as follows:
1. Open the comments in ES90en.java.
2. Open the comment in ES93en-ES94en-configuration. xml and comment out the existing Mapper
3. Delete UserMapper.xml file
This is the Mapper configuration of Mybatis in Annotation style. I personally prefer the XML approach, so future tutorials will be written in the XML configuration.