01.基于IDEA搭建mybatis的MAVEN项目

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基础环境

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• IDEA
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• MAVEN

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工程目录

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mysql数据库

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Maven Pom

添加mybatis以及mysql的依赖包

<!--pom xml配置内容--> <?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>com.mu</groupId> <artifactId>mybatis</artifactId> <version>1.0-SNAPSHOT</version> <dependencies> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.4.1</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.29</version> </dependency> </dependencies> <build> <!--idea不会寻找src/main/java目录下的xml配置--> <resources> <resource> <directory>src/main/resources</directory> <includes> <include>**/*.properties</include> <include>**/*.xml</include> <include>**/*.tld</include> </includes> <filtering>false</filtering> </resource> <resource> <directory>src/main/java</directory> <includes> <include>**/*.properties</include> <include>**/*.xml</include> <include>**/*.tld</include> </includes> <filtering>false</filtering> </resource> </resources> </build> </project>

创建各实体类以及mapper.xml文件

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• User.java

package com.mu.mybatis.domain; /** * Created by manunited1985 on 2017/11/23. */ public class User { private Integer userId; private String userName; private String userPassword; private String userEmail; public User(Integer userId, String userName, String userPassword, String userEmail) { this.userId = userId; this.userName = userName; this.userPassword = userPassword; this.userEmail = userEmail; } public Integer getUserId() { return userId; } public void setUserId(Integer userId) { this.userId = userId; } public String getUserName() { return userName; } public void setUserName(String userName) { this.userName = userName; } public String getUserPassword() { return userPassword; } public void setUserPassword(String userPassword) { this.userPassword = userPassword; } public String getUserEmail() { return userEmail; } public void setUserEmail(String userEmail) { this.userEmail = userEmail; } @Override public String toString() { return "User [userId=" + userId + ", userName=" + userName + ", userPassword=" + userPassword + ", userEmail=" + userEmail + "]"; } } 

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• UserMapper.java

package com.mu.mybatis.mapper; import com.mu.mybatis.domain.User; /** * Created by manunited1985 on 2017/11/24. */ public interface UserMapper { public User selectUserById(Integer userId); public List<User> selectUserAll(); public void insertUser(User user); } 

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• UserMapper.xml

<?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.mu.mybatis.mapper.UserMapper"> <!--设置domain类和数据库中表的字段一一对应，注意数据库字段和domain类中的字段名称不致，此处一定要！--> <resultMap id="BaseResultMap" type="com.mu.mybatis.domain.User"> <id column="USER_ID" property="userId" jdbcType="INTEGER" /> <result column="USER_NAME" property="userName" jdbcType="CHAR" /> <result column="USER_PASSWORD" property="userPassword" jdbcType="CHAR" /> <result column="USER_EMAIL" property="userEmail" jdbcType="CHAR" /> </resultMap> <!-- 查询单条记录 --> <select id="selectUserById" parameterType="int" resultMap="BaseResultMap"> SELECT * FROM t_user WHERE USER_ID = #{userId} </select> <!-- 查询所有记录 --> <select id="selectUserAll" resultMap="BaseResultMap"> SELECT * FROM t_user </select> <!-- 插入单条记录 --> <insert id="insertUser" parameterType="com.mu.mybatis.domain.User"> insert into t_user (USER_ID,USER_NAME,USER_PASSWORD,USER_EMAIL) values (#{userId},#{userName},#{userPassword},#{userEmail}) </insert> </mapper>

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• Main.java

package com.mu.mybatis; import com.mu.mybatis.domain.User; import com.mu.mybatis.mapper.UserMapper; 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 java.io.InputStream; import java.io.IOException; import java.util.List; /** * Created by manunited1985 on 2017/11/23. */ public class Main { public static void main(String[] args) throws IOException { SqlSession session = null; try { // 读取配置信息 String resource = "application.xml"; InputStream inputStream = Resources.getResourceAsStream(resource); SqlSessionFactoryBuilder builder = new SqlSessionFactoryBuilder(); // 选择不同的环境 String env = "product"; SqlSessionFactory factory = builder.build(inputStream,env); // 产生SqlSession对象 session = factory.openSession(); System.out.println(session); // 获取映射对象 UserMapper userMapper = session.getMapper(UserMapper.class); // 获取id为1的账户 User user = userMapper.selectUserById(1); System.out.println(user); // 获取所有账户 List<User> arrayList = userMapper.selectUserAll(); System.out.println(arrayList); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } finally { if (session != null) // 关闭连接 session.close(); } } } 

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数据库配置 jdbc.properties

jdbc_driver=com.mysql.jdbc.Driver jdbc_url=jdbc\:mysql\://127.0.0.1\:3306/test?useUnicode=true&characterEncoding=utf-8 jdbc_username=root jdbc_password=123456

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应用配置application.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 resource="jdbc.properties"></properties> <environments default="development"> <!--配置不同的环境下的数据源--> <!--开发模式下--> <environment id="development"> <transactionManager type="JDBC"/> <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> <!--生产模式下--> <environment id="product"> <transactionManager type="JDBC"/> <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> </environments> <mappers> <mapper resource="com/mu/mybatis/mapper/UserMapper.xml"/> </mappers> </configuration>

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运行结果

org.apache.ibatis.session.defaults.DefaultSqlSession@454b70a9 User [userId=1, userName=xiaoming, userPassword=123456, userEmail=x@sina.com] [User [userId=1, userName=xiaoming, userPassword=123456, userEmail=x@sina.com], User [userId=2, userName=tom, userPassword=123, userEmail=tom@sina.com], User [userId=3, userName=jack, userPassword=123, userEmail=jack@sina.com]] 

备注

如果你利用IDEA创建的工程,在加载mapper.xml文件的时候,出现类似现象:

mybatis错误——java.io.IOException: Could not find resource com/xxx/xxxMapper.xml

那么,你可以在pom.xml文件的添加如下字段:

 <build> <!--idea不会寻找src/main/java目录下的xml配置--> <resources> <resource> <directory>src/main/java</directory> <includes> <include>**/*.xml</include> </includes> </resource> </resources> </build>

IDEA是不会编译src的java目录的xml文件，所以在Mybatis的配置文件中找不到xml文件！（也有可能是Maven构建项目的问题，网上教程很多项目是普通的Java web项目，所以可以放到src下面也能读取到）