Mybatis中使用databaseIdProvider支持多数据库支持

秒速五厘米 2023-02-14 07:55 8阅读 0赞

我们如何让mybatis更好的同时支持多数据的操作。在更换数据库时无需做更多的操作，只需修改一下mybatis的核心配置文件既可  
pom文件

<dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.6</version>
        </dependency>
    
    
        
        <dependency>
            <groupId>com.oracle</groupId>
            <artifactId>ojdbc6</artifactId>
            <version>11.2.0.4.0-atlassian-hosted</version>
        </dependency>

mybatis配置文件

<?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 resource="jdbc.properties"/>
    
        <typeAliases>
            <package name="com.zxf.pojo"/>
        </typeAliases>
        
        
        <environments default="mysql_1"> 
            <environment id="mysql_1">
                <transactionManager type="JDBC"></transactionManager>
                <dataSource type="POOLED">
                    <property name="driver" value="${jdbc.driver}"/>
                    <property name="url" value="${jdbc.url}"/>
                    <property name="username" value="${jdbc.username}"/>
                    <property name="password" value="${jdbc.password}"/>
                </dataSource>
            </environment>
    
            <environment id="oracle_1">  
                <transactionManager type="JDBC"></transactionManager>
                <dataSource type="POOLED">
                    <property name="driver" value="${oracle.driver}"/>
                    <property name="url" value="${oracle.url}"/>
                    <property name="username" value="${oracle.user}"/>
                    <property name="password" value="${oracle.pwd}"/>
                </dataSource>
            </environment>
        </environments>
        
        <databaseIdProvider type="DB_VENDOR">
            <property name="MySQL" value="mysql"/> 
            <property name="Oracle" value="oracle"/>
            <property name="SQL Server" value="sqlserver"/>
        </databaseIdProvider>
        
        <mappers>
            <mapper resource="mappers/EmployeeMapper.xml"/>
        </mappers>
    </configuration>

jdbc.properties

jdbc.driver=com.mysql.jdbc.Driver
    jdbc.url=jdbc:mysql://192.168.0.148:3306/test
    jdbc.username=root
    jdbc.password=abc123
    
    oracle.driver=oracle.jdbc.OracleDriver
    oracle.url=jdbc:oracle:thin:@localhost:1521:orcl
    oracle.user=scott
    oracle.pwd=abc123

pojo类

package com.zxf.pojo;
    
    
    public class Employee { 
        private String emp_no;
        private String emp_name;
    
        public String getEmp_name() { 
            return emp_name;
        }
    
        public void setEmp_name(String emp_name) { 
            this.emp_name = emp_name;
        }
    
        public String getEmp_no() { 
    
            return emp_no;
        }
    
        public void setEmp_no(String emp_no) { 
            this.emp_no = emp_no;
        }
    }

Mapper接口

package com.zxf.mapper;
    
    import com.zxf.pojo.Employee;
    
    import java.util.List;
    
    public interface EmployeeMapper { 
        public List<Employee> getAll();
        public Employee getByIdEmp(String emp_no);
    }

Mapper映射文件

<?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.zxf.mapper.EmployeeMapper">
      <select id="getAll" resultType="employee" databaseId="mysql"> 
             select * from employee_basic
         </select>
     <select id="getAll" resultType="employee" databaseId="oracle">
            select ENAME emp_name     from emp
        </select>
        <select id="getByIdEmp" resultType="employee">
            select * from employee_basic where emp_no=#{ emp_no}
        </select>
    </mapper>

最后测试运行的时候，如果要切换数据库；修改这里就可以了  
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