• 重新整理,MyBatis3之初步,实体的增加、修改、删除、查询


    一、环境

    mybatis-3.2版本,jdk1.8版本,Oracle数据库

    二、准备工作

    1. 下载mybatis-3.2,需要引用其中的若干包

    mybatis-3.2.0.jar
        lib/asm-3.3.1.jar
        lib/cglib-2.2.2.jar
        lib/commons-logging-1.1.1.jar
        lib/javassist-3.17.1-GA.jar
        lib/log4j-1.2.17.jar
        lib/slf4j-api-1.7.2.jar
        lib/slf4j-log4j12-1.7.2.jar

    2 项目的目录结构

    com.clzhang.mybatis.mapper      MemberUserMapper.java          MyBatis的mapper处理类
    com.clzhang.mybatis.entity      MemberUserBean.java           MyBatis的entity类
    com.clzhang.test                MyBatisTest1.java            测试类,最终应该是在service的package中调用mapper中的方法。
    
    
    resourcesconfig  mybatis-config.xml        MyBatis的配置文件
    resourcescomclzhangmybatismapper  MemberUserMapper.xml      MyBatis的mapper配置文件

    3.假定数据库已经创建,表结构也已经创建,并且有测试数据

    CREATE TABLE MEMBER_USER (
    ID NUMBER NOT NULL PRIMARY KEY,
    NAME VARCHAR2(30),
    PERSONMOBILE VARCHAR2(20),
    ADDRESS VARCHAR2(255),
    AGE NUMBER);
    
    CREATE SEQUENCE SEQ_MEMBER_USER;

    三、具体步骤

    1. 创建entity类

    package com.clzhang.mybatis.entity;
    
    public class MemberUserBean {
        private int id;
        private String name;
        private String personMobile;
        private String address;
        private int age;
    
        public int getId() {
            return id;
        }
    
        public void setId(int id) {
            this.id = id;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        public String getPersonMobile() {
            return personMobile;
        }
    
        public void setPersonMobile(String personMobile) {
            this.personMobile = personMobile;
        }
    
        public String getAddress() {
            return address;
        }
    
        public void setAddress(String address) {
            this.address = address;
        }
    
        public int getAge() {
            return age;
        }
    
        public void setAge(int age) {
            this.age = age;
        }
    
    }
    View Code

    2. 创建mapper类

    package com.clzhang.mybatis.mapper;
    
    import java.util.*;
    import com.clzhang.mybatis.entity.MemberUserBean;
    
    public interface MemberUserMapper {
        public void insertUser(MemberUserBean user);    
        public void updateUser(MemberUserBean user);    
        public void deleteUser(int id);    
        public MemberUserBean getUser(int id); 
        public HashMap getUserHashMap(int id); 
        public List getUsersByAge(int startAge, int endAge); 
    }
    View Code

    3. 创建mybatis-config.xml的配置文件,位置于resources/config目录

    <?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> 
        <settings> 
            <setting name="cacheEnabled" value="false" /> 
            <setting name="useGeneratedKeys" value="true" /> 
            <setting name="defaultExecutorType" value="REUSE" /> 
        </settings> 
        <typeAliases> 
           <typeAlias alias="MemberUser" type="com.clzhang.mybatis.entity.MemberUserBean"/> 
        </typeAliases> 
        <environments default="development"> 
           <environment id="development"> 
               <transactionManager type="JDBC"/> 
               <dataSource type="POOLED"> 
                  <property name="driver" value="oracle.jdbc.driver.OracleDriver"/> 
                  <property name="url" value="jdbc:oracle:thin:@127.0.0.1:1521:orcl"/> 
                  <property name="username" value="mytest"/> 
                  <property name="password" value="test001"/> 
               </dataSource> 
           </environment> 
        </environments> 
        <mappers> 
            <mapper resource="com/clzhang/mybatis/mapper/MemberUserMapper.xml" /> 
        </mappers> 
    </configuration>

    4. 创建MemberUserMapper.xml配置文件,位置于:resourcescomclzhangmybatismapper

    <?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.clzhang.mybatis.mapper.MemberUserMapper">
        <!--
        默认情况下是没有开启缓存的,下条代码是开启二级缓存的,作用如下:
        1.•映射语句文件中的所有 select 语句将会被缓存。
        2.•映射语句文件中的所有 insert,update 和 delete 语句会刷新缓存。
        3.•缓存会使用 Least Recently Used(LRU,最近最少使用的)算法来收回。
        ......
        -->
        <cache />
        
        <!--以单个对象方式返回-->
        <select id="getUser" resultType="MemberUser" parameterType="int">
        select
          ID,
          NAME,
          PERSONMOBILE,
          ADDRESS,
          AGE
          FROM MEMBER_USER
        WHERE ID = #{id}
        </select>
    
        <!--以HashMap方式返回单个实例,包含列名与值的映射-->
        <select id="getUserHashMap" resultType="hashmap" parameterType="int">
        select
          ID,
          NAME,
          PERSONMOBILE,
          ADDRESS,
          AGE
          FROM MEMBER_USER
        WHERE ID = #{id}
        </select>
    
        <resultMap type="MemberUser" id="userAgeMap">  
            <id property="id" column="id"/>  
            <!--有需要做数据库到实体类名称转换的,可以写在这里-->
            <!--
            <result property="objname" column="dbname"/>
            -->
        </resultMap>  
    
        <!--以List方式返回多个结果-->
        <!--参数名称目前不可以自行指定(无法与Mapper中保持一致),待查-->
        <select id="getUsersByAge" resultMap="userAgeMap" parameterType="int">
        <![CDATA[
        select
          ID,
          NAME,
          PERSONMOBILE,
          ADDRESS,
          AGE
          FROM MEMBER_USER
        WHERE AGE > #{param1} AND AGE < #{param2}
        ]]>
        </select>
        
        <!--Oracle的实现自增长主键的方式-->
        <insert id="insertUser" parameterType="MemberUser">
        <selectKey keyProperty="id" resultType="int" order="BEFORE">
          select SEQ_MEMBER_USER.nextval from DUAL
        </selectKey>
          INSERT INTO MEMBER_USER (ID, NAME, PERSONMOBILE, ADDRESS, AGE)
          VALUES(#{id}, #{name}, #{personMobile}, #{address}, #{age})
        </insert>
    
        <update id="updateUser" parameterType="MemberUser">
          update MEMBER_USER set
            NAME = #{name},
            PERSONMOBILE = #{personMobile},
            ADDRESS = #{address},
            AGE = #{age}
          where id = #{id}
        </update>
    
        <delete id="deleteUser" parameterType="int">
          delete from MEMBER_USER where ID = #{id}
        </delete>
    </mapper>

    5. 创建测试类 

    package com.clzhang.test;
    
    import java.io.IOException;
    import java.io.Reader;
    import java.util.*;
    
    import org.apache.ibatis.io.Resources;
    import org.apache.ibatis.session.SqlSession;
    import org.apache.ibatis.session.SqlSessionFactory;
    import org.apache.ibatis.session.SqlSessionFactoryBuilder;
    
    import org.junit.Test;
    
    import com.clzhang.mybatis.mapper.MemberUserMapper;
    import com.clzhang.mybatis.entity.MemberUserBean;
    
    /**
     * mybatis的测试类,真正的应用,应该在service包中调用。
     * @author Administrator
     *
     */
    public class MyBatisTest1 {
        private static final String MYBATIS_CONFIG_FILENAME = "config/mybatis-config.xml";
        private static SqlSessionFactory sqlSessionFactory;
        
        static {
            Reader reader = null;
            try {
                reader = Resources.getResourceAsReader(MYBATIS_CONFIG_FILENAME);
            } catch (IOException e) {
                System.out.println(e.getMessage());
            }
            // 一旦你创建了 SqlSessionFactory 后,SqlSessionFactoryBuilder这个类就不需要存在了。
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
        }
        
        /**
         * SqlSessionFactory 应该在你的应用执行期间都存在。没有理由来处理或重新创建它。
         * @return
         */
        public static SqlSessionFactory getSqlSessionFactory() {
            return sqlSessionFactory;
        }
    
    //    @Test
        public void testInert() {
            // SqlSession 的实例不能被共享,也是线程不安全的。因此最佳的范围是请求或方法范围。
            SqlSession sqlSession = getSqlSessionFactory().openSession();
            try {
                // 从技术上来说,当被请求时,任意映射器实例的最宽范围和 SqlSession 是相同的。最佳范围是方法范围。
                MemberUserMapper mapper = sqlSession
                        .getMapper(MemberUserMapper.class);
                
                MemberUserBean memberUser = new MemberUserBean();
                // 因为ID为自增长字段,所以此处不需要设置
                memberUser.setName("李勇");
                memberUser.setPersonMobile("998877");
                memberUser.setAddress("江苏某地方");
                memberUser.setAge(38);
                
                mapper.insertUser(memberUser);
                sqlSession.commit();
                
                // 查看新加的对象主键
                System.out.println("新加对象的id:" + memberUser.getId());
            } finally {
                sqlSession.close();
            }
        }
    
    //  @Test
      public void testUpdate() {
          SqlSession sqlSession = getSqlSessionFactory().openSession();
          try {
              MemberUserMapper mapper = sqlSession
                      .getMapper(MemberUserMapper.class);
              
              // 先查询,后更新
              MemberUserBean memberUser = mapper.getUser(8);
              memberUser.setName("赵五副本");
              memberUser.setPersonMobile("12345");
              memberUser.setAddress("天津上地某公司");
              memberUser.setAge(29);
              
              mapper.updateUser(memberUser);
              sqlSession.commit();
          } finally {
              sqlSession.close();
          }
          }
      
    //    @Test
        public void testDelete() {
            SqlSession sqlSession = getSqlSessionFactory().openSession();
            try {
                MemberUserMapper mapper = sqlSession.getMapper(MemberUserMapper.class);
    
                // 直接设置ID主键,然后删除
                mapper.deleteUser(2);
                sqlSession.commit();
            } finally {
                sqlSession.close();
            }
        }
    
    //    @Test
        public void getUser() {
            SqlSession sqlSession = getSqlSessionFactory().openSession();
            try {
                MemberUserMapper mapper = sqlSession
                        .getMapper(MemberUserMapper.class);
                MemberUserBean memberUser = mapper.getUser(5);
                
                System.out.println("name:" + memberUser.getName() + "	mobile:"
                        + memberUser.getPersonMobile() + "	address:" + memberUser.getAddress());
            } finally {
                sqlSession.close();
            }
        }
    
    //    @Test
        public void getUserHashMap() {
            SqlSession sqlSession = getSqlSessionFactory().openSession();
            try {
                MemberUserMapper mapper = sqlSession
                        .getMapper(MemberUserMapper.class);
                HashMap<String, Object> hashMap = mapper.getUserHashMap(5);
                for (Map.Entry<String, Object> entry : hashMap.entrySet()) {
                    String key = entry.getKey();
                    Object value = entry.getValue();
                    
                    System.out.println(key + ":" + value);
                }
            } finally {
                sqlSession.close();
            }
        }
    
        @Test
        public void getUserByAge() {
            SqlSession sqlSession = getSqlSessionFactory().openSession();
            try {
                MemberUserMapper mapper = sqlSession
                        .getMapper(MemberUserMapper.class);
                List<MemberUserBean> myList = mapper.getUsersByAge(20, 40);
                for (MemberUserBean entry : myList) {
                    int key = entry.getId();
                    String value = entry.getAddress();
    
                    System.out.println(key + ":" + value);
                }
            } finally {
                sqlSession.close();
            }
        }    
    }

    四、单独测试各个模块

    解除注释JUnit各单元,然后键盘输入:alt+shift+X,T,分别进行测试。

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  • 原文地址:https://www.cnblogs.com/nayitian/p/14990087.html
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