mybatis是怎样访问数据库

发布网友发布时间：2022-04-30 01:56

共2个回答

懂视网时间：2022-04-30 06:17

package com.disappearwind.service; 2 3 import org.springframework.beans.factory.annotation.Autowired; 4 import org.springframework.stereotype.Repository; 5 import org.springframework.stereotype.Service; 6 7 import com.disappearwind.mapper.UserInfoMapper; 8 import com.disappearwind.model.UserInfo; 9 10 11 /** 12 * 用户service 13 * 14 */ 15 @Service 16 @Repository 17 public class UserInfoService{ 18 19 @Autowired 20 private UserInfoMapper userInfoMapper; 21 22 public UserInfo selectByPrimaryKey(Integer id){ 23 return userInfoMapper.selectByPrimaryKey(id); 24 } 25 } UserInfoService

2. Mapper层申明

1 package com.disappearwind.mapper;
2 
3 import com.disappearwind.model.UserInfo;
4 
5 public interface UserInfoMapper {
6  UserInfo selectByPrimaryKey(Integer id);
7 }

UserInfoMapper

3. mpper.xml配置文件

 1 <?xml version="1.0" encoding="UTF-8" ?>
 2 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
 3 
 4 <mapper namespace="com.disappearwind.mapper.UserInfoMapper" >
 5 
 6 <resultMap id="BaseResultMap" type="com.disappearwind.model.UserInfo">
 7  <id column="UserInfoID" property="userinfoid" jdbcType="INTEGER" />
 8  <result column="Name" property="username" jdbcType="VARCHAR" />
 9  <result column="Phone" property="phone" jdbcType="CHAR" />
10  <result column="Pwd" property="pwd" jdbcType="CHAR" />
11 </resultMap>
12 
13 <sql id="Base_Column_List">
14  UserInfoID, Name, Type, TypeRemark, HeadUrl,BigImgUrl,GreatImgUrl,
15  NickName, Sex, Status,Labels, StoryCount,
16  FriendCount, FollowerCount, FavouriteCount, HotNum,
17  CreateDate,Description
18 </sql>
19 
20 <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Integer" >
21  select 
22 <include refid="Base_Column_List" />
23  from userinfo
24  where UserInfoID = #{userinfoid,jdbcType=INTEGER}
25 </select>
26 
27 </mapper>

UserInfoMapper.xml

4. 实体model层

 1 package com.disappearwind.model;
 2 
 3 public class UserInfo {
 4 private Integer userinfoid;
 5 
 6 private String username;
 7 
 8 private String phone;
 9 
10 private String pwd;
11 
12 public Integer getUserinfoid() {
13  return userinfoid;
14  }
15 
16 public void setUserinfoid(Integer userinfoid) {
17  this.userinfoid = userinfoid;
18  }
19 
20 public String getUsername() {
21  return username;
22  }
23 
24 public void setUsername(String username) {
25  this.username = username;
26  }
27 
28 public String getPhone() {
29  return phone;
30  }
31 
32 public void setPhone(String phone) {
33  this.phone = phone;
34  }
35 
36 public String getPwd() {
37  return pwd;
38  }
39 
40 public void setPwd(String pwd) {
41  this.pwd = pwd;
42  }
43 
44 public UserInfo() {
45  }
46 }

UserInfo

5. SpringMVC配置

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <beans xmlns="http://www.springframework.org/schema/beans"
 3  xmlns:p="http://www.springframework.org/schema/p" xmlns:context="http://www.springframework.org/schema/context"
 4  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:tx="http://www.springframework.org/schema/tx"
 5  xmlns:aop="http://www.springframework.org/schema/aop"
 6  xsi:schemaLocation="
 7  http://www.springframework.org/schema/beans
 8  http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
 9  http://www.springframework.org/schema/context
10  http://www.springframework.org/schema/context/spring-context-4.0.xsd
11  http://www.springframework.org/schema/aop
12  http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
13  http://www.springframework.org/schema/tx
14  http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
15  ">
16 <context:component-scan base-package="com.disappearwind.*" />
17 </beans>

context.xml

注意：context.xml的位置在web.xml中的如下配置节配置

<context-param>
　　<param-name>contextConfigLocation</param-name>
　　<param-value>classpath:context.xml</param-value>
</context-param>

用此方案的好处：省得写DAO层，只要Mapper层的方法申明和mapper.xml的方法申明保持一致，并且文件名也保持一致（UserInfoMapper.java和UserInfoMapper.xml）就能顺利的访问

Mybatis基于注解的方式访问数据库

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热心网友时间：2022-04-30 03:25

1，首先在包下创建Configuration.xml文件，该文件的格式如下：
　　< xml version="1.0" encoding="UTF-8" > <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" ""> <configuration> <environments default="dev"> <environment id="dev"> <transactionManager type="JDBC"$amp;>amp;$lt;/transactionManager> <dataSource type="POOLED"> <property name="driver" value="oracle.jdbc.driver.OracleDriver" /> <property name="url" value="jdbc:oracle:thin:@192.168.1.20:1521:oa" /> <property name="username" value="zhangsan" /> <property name="password" value="123" /> </dataSource> </environment> </environments> <mappers> <mapper resource="com/cissst/oa/data/UserMapper.xml" /> <mapper resource="com/cissst/oa/data/DepartmentMapper.xml" /> </mappers> </configuration>
　　2，使用myBatis提供的工具类中的方法,从类路径或Configuration.xml文档所在位置加载资源文件。
　　SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder();　
　　SqlSessionFactory factory = null;　
　　// 获取SqlSessionFactory对象
　　try {　
　　Reader reader = Resources　
　　.getResourceAsReader("com/cissst/oa/data/Configuration.xml");　
　　factory = builder.build(reader);　
　　} catch (Exception e) {　
　　e.printStackTrace();　
　　}　
　　3，使用工厂对象获取SqlSession 对象
　　SqlSession session=factory .openSession(false);　
　　参数如果为true，表示该会话具有自动提交事务的功能，否则需程序员手动提交事务。
　　4，使用进行数据库访问
　　SqlSession session = super.getSqlSession();　
　　// 构造返回值集合
　　List<UserEntity> result = new ArrayList<UserEntity>();　
　　try {　
　　// 获取映射接口
　　UserMapper userMapper = session.getMapper(UserMapper.class);　
　　// 调用接口中的方法
　　List<UserEntity> list = userMapper.getUserList(userEntity);　
　　// 提交事务
　　session.commit();　
　　} catch (Exception e) {　
　　// 回滚事务
　　session.rollback();　
　　} finally {　
　　// 关闭会话
　　session.close();　
　　}　