1.参数的传递
1)形参的索引,#{0}从0开始
2)形参的索引,#{param1}从1开始
3)对象,通过对象的属性访问
4)Map,通过key来访问
5)注解(@Param("name"))
6)用那个
1)如果方法的参数大于3个要么封装成对象,要么封装成Map
2)如果方法的形参小于3个参数就用注解
创建数据库:
1.创建项目
2.建包建配置文件
com.qf.entity
com.qf.dao
com.qf.mapper
com.qf.utils
mybatis-config.xml
3.con.qf.entity包中创建实体类
package com.qf.entity; import org.apache.ibatis.type.Alias; public class User { private Integer id; private String name; private String password; private String isAdmin; public String getPassword() { return password; } public void setPassword(String password) { this.password = password; } public String getName() { return name; } public void setName(String name) { this.name = name; } public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getIsAdmin() { return isAdmin; } public void setIsAdmin(String isAdmin) { this.isAdmin = isAdmin; } @Override public String toString() { return "User [id=" + id + ", name=" + name + ", password=" + password + ", isAdmin=" + isAdmin + "]"; } }
4.con.qf.dao包中创建接口
package com.qf.dao; import java.util.Map; import org.apache.ibatis.annotations.Param; import com.qf.entity.User; public interface IUserDao { public User getUserById(Integer id); public void add(User user); public User login(String name,String password); public User login2(User user); public User login3(Map<String,Object> map); public User login4(@Param("name")String name,@Param("password")String password); }
5.配置jdbc.properties配置文件
jdbc.url =jdbc:mysql://localhost:3306/1708_mybatis jdbc.name=root jdbc.password=root jdbc.driver=com.mysql.jdbc.Driver
配置mybatis-config.xml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> <!-- 加载属性文件 resource:本地资源文件 --> <properties resource="jdbc.properties"></properties> <typeAliases> <!-- 给一个对象起别名 --> <!-- <typeAlias type="com.qf.entity.User" alias="user"/> --> <!-- 给一个包下面的所有类起别名,默认的别名是类名首字母小写,可以通过@Alias注解修改默认的别名 --> <package name="com.qf.entity"/> </typeAliases> <environments default="development"> <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="${jdbc.name}" /> <property name="password" value="${jdbc.password}" /> </dataSource> </environment> </environments> </configuration>
6.com.qf.mapper包创建接口的映射文件
<?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"> <!-- namespace指的就是接口的全类名 --> <mapper namespace="com.qf.dao.IUserDao"> <resultMap type="com.qf.entity.User" id="userMap2"> <result column="is_admin" property="isAdmin" /> </resultMap> <resultMap type="com.qf.entity.User" id="userMap" extends="userMap2"> <id column="id" property="id" /> <result column="name" property="name" /> <result column="password" property="password" /> </resultMap> <!-- id:方法名称 resultType:返回类型 --> <select id="getUserById" resultMap="userMap"> select * from t_user where id = #{id} </select> <!-- parameterType:方法的参数类型 --> <insert id="add" parameterType="user"> insert into t_user (name,password) values(#{name},#{password}) </insert> <!--第一种方式通过方法形参的索引,从0开始 --> <!-- <select id="login" resultMap="userMap"> select * from t_user where name=#{0} and password=#{1} </select> --> <!--第二种方式通过方法形参的索引,从param1开始 --> <select id="login" resultMap="userMap"> select * from t_user where name=#{param1} and password=#{param2} </select> <!-- 第三种方式通过方法是个对象,通过属性名从取值 --> <select id="login2" resultMap="userMap" parameterType="User"> select * from t_user where name=#{name} and password=#{password} </select> <!-- 第四种方式通过方法是个Map,通过key来取值 --> <select id="login3" resultMap="userMap" parameterType="User"> select * from t_user where name=#{name} and password=#{password} </select> <!-- 第五种方式方法传递多个参数,用注解中的中的内容来取值 --> <select id="login4" resultMap="userMap" parameterType="User"> select * from t_user where name=#{name} and password=#{password} </select> </mapper>
7.在mybatis-config.xml里面读取Mapper文件
<!-- Mapper文件 --> <mappers> <mapper resource="com/qf/mapper/IUserDao.xml" /> </mappers>
8.com.qf.util工具类
package com.qf.utils; import java.io.IOException; import java.io.InputStream; 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 org.xml.sax.InputSource; public class MyBatisUtil { private static SqlSessionFactory sqlSessionFactory; public static SqlSessionFactory getSqlSessionFactory() { if (sqlSessionFactory == null) { initSqlSessionFactory(); // 为空再去参加 } return sqlSessionFactory; } private static void initSqlSessionFactory() { InputStream ips = null; try { // 1.指定配置文件 ips = Resources.getResourceAsStream("mybatis-config.xml"); // 2.赋值操作 synchronized (MyBatisUtil.class) { if (sqlSessionFactory == null) { sqlSessionFactory = new SqlSessionFactoryBuilder().build(ips); } } } catch (IOException e) { e.printStackTrace(); } finally { if (ips != null) { try { ips.close(); } catch (IOException e) { e.printStackTrace(); } } } } }
9.测试类
package com.qf.dao; import java.util.HashMap; import java.util.Map; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.log4j.Logger; import org.junit.Test; import com.qf.entity.User; import com.qf.utils.MyBatisUtil; public class UserDaoTest { private Logger logger = Logger.getLogger(UserDaoTest.class); @Test public void testGetUserById() { SqlSession sqlSession = MyBatisUtil.getSqlSessionFactory().openSession(); IUserDao userDao = sqlSession.getMapper(IUserDao.class); User user = userDao.getUserById(7); System.out.println(user); sqlSession.close(); } /** * 测试:1第一种方式通过方法形参的索引,从0开始 */ @Test public void testLogin() { SqlSessionFactory sqlSessionFactory = MyBatisUtil.getSqlSessionFactory(); SqlSession sqlSession = sqlSessionFactory.openSession(); IUserDao userDao = sqlSession.getMapper(IUserDao.class); User user = userDao.login("张三", "123"); System.out.println(user); sqlSession.commit(); sqlSession.close(); } /** * 第二种方式通过方法形参的索引,从param1开始 */ @Test public void testLogin1() { SqlSessionFactory sqlSessionFactory = MyBatisUtil.getSqlSessionFactory(); SqlSession sqlSession = sqlSessionFactory.openSession(); IUserDao userDao = sqlSession.getMapper(IUserDao.class); User user = userDao.login("张三", "123"); System.out.println(user); sqlSession.commit(); sqlSession.close(); } /** * 第三种方式通过方法是个对象,通过属性名从取值 */ @Test public void testLogin2() { SqlSessionFactory sqlSessionFactory = MyBatisUtil.getSqlSessionFactory(); SqlSession sqlSession = sqlSessionFactory.openSession(); IUserDao userDao = sqlSession.getMapper(IUserDao.class); User user =new User(); user.setName("张三"); user.setPassword("123"); user = userDao.login2(user); System.out.println(user); sqlSession.commit(); sqlSession.close(); } /** * 第四种方式通过方法是个Map,通过key来取值 */ @Test public void testLogin3() { SqlSessionFactory sqlSessionFactory = MyBatisUtil.getSqlSessionFactory(); SqlSession sqlSession = sqlSessionFactory.openSession(); IUserDao userDao = sqlSession.getMapper(IUserDao.class); Map<String,Object> map=new HashMap<String,Object>(); map.put("name", "张三"); map.put("password", "123"); User user = userDao.login3(map); System.out.println(user); sqlSession.commit(); sqlSession.close(); } /** * 第五种方式方法传递多个参数,用注解中的中的内容来取值 */ @Test public void testLogin4() { SqlSessionFactory sqlSessionFactory = MyBatisUtil.getSqlSessionFactory(); SqlSession sqlSession = sqlSessionFactory.openSession(); IUserDao userDao = sqlSession.getMapper(IUserDao.class); User user = userDao.login4("张三", "123"); System.out.println(user); sqlSession.commit(); sqlSession.close(); } }