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mybatis实现表与对象的关联关系_动力节点Java学院整理

2019年07月19日  | 移动技术网IT编程  | 我要评论

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

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