mybatis Entry _ Power node Java College Collation

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.