mybatis实现表与对象的关联关系_动力节点Java学院整理

所需要用到的其他工具或技术:

项目管理工具 : Maven

测试运行工具 : Junit

数据库 : Derby

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 建表及数据插入（新建一个USER_TEST_TB_RELATIONSHIP表，然后CopyUSER_TEST_TB的数据，Derby不支持表结构中列名的修改，只能这么做了）:

CREATE TABLE USER_TEST_TB_RELATIONSHIP(
USER_ID INT PRIMARY KEY,
USER_USERNAME VARCHAR(20) NOT NULL,
USER_PASSWORD VARCHAR(20) NOT NULL,
USER_NICKNAME VARCHAR(20) NOT NULL
);
 INSERT INTO USER_TEST_TB_RELATIONSHIP(USER_ID,USER_USERNAME,USER_PASSWORD,USER_NICKNAME) SELECT ID,USERNAME,PASSWORD,NICKNAME FROM USER_TEST_TB; 

Mybatis配置文件 src/main/resource源目录下

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/bjpowernode;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 resource="com/bjpowernode/practice/UserMapper.xml" />
  </mappers>
</configuration>  

User.java对象类(src/main/java/com/bjpowernode/practice目录下)

package com.bjpowernode.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.xml  Mapper文件（src/main/java/com.bjpowernode.practice目录下）

<?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.bjpowernode.practice.UserMapper">
  <!-- 对象属性和表字段的对应 -->
  <resultMap id="userResultMap" type="com.bjpowernode.practice.User">
    <result property="id" column="USER_ID"/>
    <result property="username" column="USER_USERNAME"/>
    <result property="password" column="USER_PASSWORD"/>
    <result property="nickname" column="USER_NICKNAME"/>
  </resultMap>
  <select id="getUser" resultMap="userResultMap">
    select *
    from USER_TEST_TB_RELATIONSHIP
  </select>
</mapper> 

UserMapper.java Mapper类（src/main/java/com.bjpowernode.practice目录下）

package com.bjpowernode.practice;
import java.util.List;
public interface UserMapper
{
  public List<User> getUser();
} 

测试类TestMyBatis.Java（src/test/java/com.bjpowernode.practice目录下）

package com.bjpowernode.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()
  {
    /**
     * 准备Mybatis运行环境
     */
    source = "test-mybatis-configuration.xml";
    inputStream = TestMyBatis.class.getClassLoader().getResourceAsStream(source);
    sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
  }
  @Test
  public void testGet()
  {
    try
    {
      // 获取Session连接
      SqlSession session = sqlSessionFactory.openSession();
      // 获取Mapper
      UserMapper userMapper = session.getMapper(UserMapper.class);
      // 显示User信息
      System.out.println("Test Get start...");
      this.printUsers(userMapper.getUser());
      System.out.println("Test Get finished...");
    }
    catch (Exception e)
    {
      e.printStackTrace();
    }
  }
  /**
   *
   * 打印用户信息到控制台
   *
   * @param users
   */
  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());
    }
  }
}

总结

以上所述是小编给大家介绍的mybatis实现表与对象的关联关系_动力节点Java学院整理，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对我们网站的支持！