一、Mybatis下载与使用
下载地址：https://github.com/mybatis/mybatis-3/releases
下载后解压目录：
需要将lib下的jar包和mybatid-x-x-x.jar包导入（数据库驱动也需要导入）。
二、mybatis工作流程
2.1 读取mybatis-config.xml配置文件。
2.2 根据mybatis-config.xml中的
2.3 通过mybatis-config.xml构建SqlSessionFactory。
2.4 通过SqlSessionFactory创建sqlSession（包含执行SQL的烦烦烦）。
2.5 mybatis生成executor接口用于操作数据库，它会根据传递的参数来生成需要执行的sql语句。
2.6 executor接口有一个MapperStatement类型的参数（包含SQL语句的id、参数等信息）。
2.7 MapperStatement将传递的参数映射到需要执行的sql语句中，类似JDBC中给sql语句设置参数。
2.8 execute将数据库执行结果映射到对应java对象。
三、Mybatis基本增删改查
首先 建立t_customer表，建表语句如下：
CREATE TABLE `t_customer` ( `id` int(32) NOT NULL AUTO_INCREMENT, `username` varchar(50) DEFAULT NULL, `jobs` varchar(50) DEFAULT NULL, `phone` varchar(16) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB AUTO_INCREMENT=9 DEFAULT CHARSET=utf8;
建立完表后，我们首先使用mybatis添加数据。
准备工作：
首先需要在src目录下新建log4j.properties文件（可用采用Properties）。
log4j.properties
# Global logging configuration log4j.rootLogger=ERROR, stdout # MyBatis logging configuration... log4j.logger.com.mybatis=DEBUG //com.mybatis是本地包名，指该包下所有类的日志级别为DEBUG # Console output... log4j.appender.stdout=org.apache.log4j.ConsoleAppender log4j.appender.stdout.layout=org.apache.log4j.PatternLayout log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n
3.1增加用户
Customer.java (用户类)
public class Customer { private Integer id; private String username; private String jobs; private String phone; public int 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 getJobs() { return jobs; } public void setJobs(String jobs) { this.jobs = jobs; } public String getPhone() { return phone; } public void setPhone(String phone) { this.phone = phone; } @Override public String toString() { return "Customer [id=" + id + ", username=" + username + ", jobs=" + jobs + ", phone=" + phone + "]"; } }
在src目录下创建一个包（com.xxx.xxx.mapper），在该包下创建文件CustomerMapper.xml
CustomerMapper.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.mybatis.mapper.CustomerMapper" >
<insert id = "addCustomer" parameterType = "com.mybatis.first.Customer">
insert into t_customer(username, jobs,phone)
value(#{username}, #{jobs}, #{phone})
insert>
mapper>
#{}代表一个占位符，#{username}代表接收Customer类型中属性名为username的属性值。
在src目录下创建mybatis-config.xml
mybatis-config.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>
<environments default = "mysql">
<environment id = "mysql">
<transactionManager type = "JDBC"/>
<dataSource type = "POOLED">
<property name = "driver" value = "com.mysql.jdbc.Driver" />
<property name = "url" value = "jdbc:mysql://localhost:3306/mybatis" />
<property name = "username" value = "root" />
<property name = "password" value = "123456" />
dataSource>
environment>
environments>
<mappers>
<mapper resource = "com/mybatis/mapper/CustomerMapper.xml"/>
mappers>
configuration>
测试添加用户：
import java.io.IOException; import java.io.InputStream; import java.util.List; import org.apache.ibatis.io.Resources; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder; public class MybatisTest { public static void main(String[] args) throws IOException { String resource = "mybatis-config.xml"; //获取配置文件输入流 InputStream inputStream = Resources.getResourceAsStream(resource); //通过配置文件输入流构建sqlSessionFactory, SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); //通过sqlSessionFactory获取sqlSession，true代表设置为自动提交。 SqlSession sqlSession = sqlSessionFactory.openSession(true); //创建客户 Customer customer = new Customer(); customer.setUsername("hcf"); customer.setJobs("student"); customer.setPhone("13611110007"); //执行CustomerMapper.xml文件中，id为xxxCustomer的语句，参数为customer对象。 int num = sqlSession.insert("com.mybatis.mapper.CustomerMapper.addCustomer", customer); System.out.println(num); //如果没有设置自动提交，使用insert、update、delete时需要使用sqlSession.commit()手动提交。 sqlSession.close(); } }
传递的参数为customer，插入语句中#{xxx}代表对象中属性名为xxx的值。
3.2删除客户
再CustomerMapper.xml文件中添加删除语句即可。
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.mybatis.mapper.CustomerMapper" >
<insert id = "addCustomer" parameterType = "com.mybatis.first.Customer">
insert into t_customer(username, jobs,phone)
value(#{username}, #{jobs}, #{phone})
insert>
<delete id = "deleteCustomer" parameterType = "Integer">
delete from t_customer where id = #{id}
delete>
mapper>
测试删除
import java.io.IOException; import java.io.InputStream; import java.util.List; import org.apache.ibatis.io.Resources; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder; public class MybatisTest { public static void main(String[] args) throws IOException { String resource = "mybatis-config.xml"; //获取配置文件输入流 InputStream inputStream = Resources.getResourceAsStream(resource); //通过配置文件输入流构建sqlSessionFactory, SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); //通过sqlSessionFactory获取sqlSession，true代表设置为自动提交。 SqlSession sqlSession = sqlSessionFactory.openSession(true); //创建客户 Customer customer = new Customer(); customer.setId(9); customer.setUsername("hcf"); customer.setJobs("student"); customer.setPhone("13611110007"); //执行CustomerMapper.xml文件中，id为xxxCustomer的语句，参数为Integer对象。 int num = sqlSession.delete("com.mybatis.mapper.CustomerMapper.deleteCustomer", 9); System.out.println(num); //如果没有设置自动提交，使用insert、update、delete时需要使用sqlSession.commit()手动提交。 sqlSession.close(); } }
3.3修改用户
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.mybatis.mapper.CustomerMapper" >
<insert id = "addCustomer" parameterType = "com.mybatis.first.Customer">
insert into t_customer(username, jobs,phone)
value(#{username}, #{jobs}, #{phone})
insert>
<update id = "updateCustomer" parameterType = "com.mybatis.first.Customer">
update t_customer set
username = #{username}, jobs = #{jobs}, phone = #{phone}
where id = #{id}
update>
<delete id = "deleteCustomer" parameterType = "Integer">
delete from t_customer where id = #{id}
delete>
mapper>
测试修改：
import java.io.IOException; import java.io.InputStream; import java.util.List; import org.apache.ibatis.io.Resources; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder; public class MybatisTest { public static void main(String[] args) throws IOException { String resource = "mybatis-config.xml"; //获取配置文件输入流 InputStream inputStream = Resources.getResourceAsStream(resource); //通过配置文件输入流构建sqlSessionFactory, SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); //通过sqlSessionFactory获取sqlSession，true代表设置为自动提交。 SqlSession sqlSession = sqlSessionFactory.openSession(true); //创建客户 Customer customer = new Customer(); customer.setId(9); customer.setUsername("hcf"); customer.setJobs("student"); customer.setPhone("13611110007"); //执行CustomerMapper.xml文件中，id为xxxCustomer的语句，参数为customer对象。 int num = sqlSession.update("com.mybatis.mapper.CustomerMapper.updateCustomer", customer); System.out.println(num); //如果没有设置自动提交，使用insert、update、delete时需要使用sqlSession.commit()手动提交。 sqlSession.close(); } }
首先数据库类有一条数据：
然后我们运行修改语句。
3.4查询用户
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.mybatis.mapper.CustomerMapper" >
<select id="findCustomerById" parameterType = "Integer"
resultType = "com.mybatis.first.Customer">
select * from t_customer where id = #{id}
select>
<select id = "findCustomerByName" parameterType = "String"
resultType = "com.mybatis.first.Customer">
select * from t_customer where username like '%${value}%'
select>
<insert id = "addCustomer" parameterType = "com.mybatis.first.Customer">
insert into t_customer(username, jobs,phone)
value(#{username}, #{jobs}, #{phone})
insert>
<update id = "updateCustomer" parameterType = "com.mybatis.first.Customer">
update t_customer set
username = #{username}, jobs = #{jobs}, phone = #{phone}
where id = #{id}
update>
<delete id = "deleteCustomer" parameterType = "Integer">
delete from t_customer where id = #{id}
delete>
mapper>
测试查询
import org.apache.ibatis.io.Resources; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder; public class MybatisTest { public static void main(String[] args) throws IOException { String resource = "mybatis-config.xml"; //获取配置文件输入流 InputStream inputStream = Resources.getResourceAsStream(resource); //通过配置文件输入流构建sqlSessionFactory, SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); //通过sqlSessionFactory获取sqlSession，true代表设置为自动提交。 SqlSession sqlSession = sqlSessionFactory.openSession(true); //执行CustomerMapper.xml文件中，id为xxxCustomer的语句，参数为Integer对象。 Listcustomers = sqlSession.selectList("com.mybatis.mapper.CustomerMapper.findCustomerById", 9); for(Customer temp : customers) { System.out.println(customers); } //如果没有设置自动提交，使用insert、update、delete时需要使用sqlSession.commit()手动提交。 sqlSession.close(); } }
