Eclipse下MyBatis简明教程
工程搭建
创建Java工程
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导入jar包
把目录（mybatis-3.2.7/lib）下的文件导入到lib目录下
asm-3.3.1.jar cglib-2.2.2.jar commons-logging-1.1.1.jar javassist-3.17.1-GA.jar log4j-1.2.17.jar log4j-api-2.0-rc1.jar log4j-core-2.0-rc1.jar mybatis-3.2.7.jar -->mybatis的核心包 mysql-connector-java-5.1.7-bin.jar -->数据库驱动包 slf4j-api-1.7.5.jar slf4j-log4j12-1.7.5.jarbuild path -> add build path
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配置日志文件
创建config文件夹用于存放配置文件在config文件夹中创建log4j.properties文件，输入如下内容
log4j.rootLogger=DEBUG, stdout log4j.appender.stdout=org.apache.log4j.ConsoleAppender log4j.appender.stdout.layout=org.apache.log4j.PatternLayout log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n -
创建po类
创建user类public class User { private Integer id; private String username; private Date birthday; private String sex; private String address; /** * get/set也需要写，这里不展示了 **/ } -
配置数据
在config文件夹中创建db.properties文件，输入如下内容jdbc.driver=com.mysql.jdbc.Driver jdbc.url=jdbc:mysql://localhost:3306/mybatis?characterEncoding=utf-8 jdbc.username=root jdbc.password=123456 -
设置sql映射文件
在config文件夹中创建user.xml文件，输入如下<?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="test"> <select id="findUserById" parameterType="java.lang.Integer" resultType="User类的包名.User"> select * from user where id=#{id} </select> </mapper> -
配置SqlMapConfig.xml
在config文件夹中创建SqlMapConfig.xml文件，输入如下<?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="db.properties"/> <environments default="development"> <environment id="development"> <!-- 使用jdbc事务管理--> <transactionManager type="JDBC" /> <!-- 数据库连接池--> <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="config/User.xml"/> </mappers> </configuration> -
测试
在测试方法中输入如下内容String resource = "SqlMapConfig.xml"; //通过流将核心配置文件读取进来 InputStream inputStream = Resources.getResourceAsStream(resource); //通过核心配置文件输入流来创建会话工厂 SqlSessionFactory factory = new SqlSessionFactoryBuilder().build(inputStream); //通过工厂创建会话 SqlSession openSession = factory.openSession(); //第一个参数:所调用的sql语句= namespace+.+sql的ID User user = openSession.selectOne("test.findUserById", 1); System.out.println(user); openSession.close();
对数据库的增删改查
1.根据id查找用户
在User.xml文件中的
<mapper namespace="test"> </mapper>
节点内添加：
<select id="findUserById" parameterType="int" resultType="User所在的包.User">
select * from user where id=#{id}
</select>
注：以下皆是在此节点下添加
2.根据用户名查找用户
<select id="findUserByUsername" parameterType="java.lang.String" resultType="User所在的包.User">
select * from user where username like '%${value}%'
</select>
3.添加用户1
<insert id="insertUser1" parameterType="User所在的包.User">
insert into user(username,birthday,sex,address) values(#{username},#{birthday},#{sex},#{address})
</insert>
4.添加用户2
<insert id="insertUser2" parameterType="User所在的包.User">
<selectKey keyProperty="id" order="AFTER" resultType="int">
select LAST_INSERT_ID()
</selectKey>
insert into user(username,birthday,sex,address) values(#{username},#{birthday},#{sex},#{address})
</insert>
5.修改用户
<update id="updateUser" parameterType="User所在的包.User">
update user set username=#{username},birthday=#{birthday},sex=#{sex},address=#{address} where id=#{id}
</update>
6.删除用户
<delete id="deleteUser" parameterType="int">
delete from user where id=#{id}
</delete>
测试
private SqlSessionFactory sqlSessionFactory;
@Before
public void createSqlSessionFactory() throws IOException {
String resource = "SqlMapConfig.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
}
@Test
public void test(){
SqlSession sqlSession = null;
sqlSession = sqlSessionFactory.openSession();
//1.根据id查找用户
//selectUserById(sqlSession);
//2.根据用户名查找用户
//selectUserByUsername(sqlSession);
//3.添加用户1
//insertUser1(sqlSession);
//4.添加用户2
//insertUser2(sqlSession);
//5.修改用户
//updateUser(sqlSession);
//6.删除用户
//deleteUser(sqlSession);
}
//1.根据id查找用户
public void selectUserById(SqlSession sqlSession){
User user = sqlSession.selectOne("test.findUserById",10);
System.out.println(user);
sqlSession.close();
}
//2.根据用户名查找用户
public void selectUserByUsername(SqlSession sqlSession){
List<User> users = sqlSession.selectList("test.findUserByUsername","小明");
for (User user : users) {
System.out.println(user);
}
sqlSession.close();
}
//3.添加用户1
public void insertUser1(SqlSession sqlSession){
User user = new User();
user.setUsername("美娜");
user.setSex("2");
user.setAddress("beijing");
sqlSession.insert("test.insertUser1",user);
sqlSession.commit();
sqlSession.close();
}
//4.添加用户2
public void insertUser2(SqlSession sqlSession){
User user = new User();
user.setUsername("小楠");
user.setSex("w");
user.setAddress("beijing");
sqlSession.insert("test.insertUser2",user);
sqlSession.commit();
sqlSession.close();
}
//5.修改用户
public void updateUser(SqlSession sqlSession){
User user = new User();
user.setUsername("美娜");
user.setSex("w");
user.setAddress("beijing");
user.setId(25);
sqlSession.update("test.updateUser", user);
sqlSession.commit();
sqlSession.close();
}
//6.修改用户
public void deleteUser(SqlSession sqlSession){
sqlSession.update("test.deleteUser", 25);
sqlSession.commit();
sqlSession.close();
}
Mapper动态代理
接口文件
Mapper接口方法名和Mapper.xml中定义的statement的id相同
Mapper接口方法的输入参数类型和mapper.xml中定义的statement的parameterType的类型相同
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Mapper接口方法的输出参数类型和mapper.xml中定义的statement的resultType的类型相同
public interface UserMapper { public User findUserById(Integer id); public List<User> findUserByUsername(String userName); }
映射文件
接口的名称和映射文件名称除扩展名外要完全相同
接口和映射文件要放在同一个目录下
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namespace的值为UserMapper接口路径
<?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="UserMapper所在的包.UserMapper"> <!-- 1.通过id查找用户 --> <select id="findUserById" parameterType="int" resultType="User所在的包.User"> select * from user where id=#{id} </select> <!-- 2.根据用户名查找用户 --> <select id="findUserByUsername" parameterType="java.lang.String" resultType="User所在的包.User"> select * from user where username like '%${value}%' </select> </mapper>
加载映射文件
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单个加载
<mapper class="UserMapper所在的包.UserMapper"/> 批量加载
1. 接口的名称和映射文件名称除扩展名外要完全相同
2. 接口和映射文件要放在同一个目录下
<package name="接口所在的包名"/>
测试
private SqlSessionFactory sqlSessionFactory;
@Before
public void createSqlSessionFactory() throws IOException {
String resource = "SqlMapConfig.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
}
@Test
public void test() throws Exception {
SqlSession sqlSession = sqlSessionFactory.openSession();
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
// 1.根据id查找用户
// selectUserById(userMapper);
// 2.根据用户名查找用户
// selectUserByUsername(userMapper);
}
// 1.根据id查找用户
public void selectUserById(UserMapper userMapper) {
User user = userMapper.findUserById(1);
System.out.println(user);
}
// 2.根据用户名查找用户
public void selectUserByUsername(UserMapper userMapper) {
List<User> users = userMapper.findUserByUsername("小明");
for (User user : users) {
System.out.println(user);
}
}
