1-----Mybatis
没有mybatis
建表
查询
import java.sql.*; public class DatabaseTest { public static void main(String[] args) throws SQLException, ClassNotFoundException { Class.forName("com.mysql.cj.jdbc.Driver"); Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT%2B8", "root", "123456"); Statement statement = conn.createStatement(); String sql = "select * from user where id = ?"; PreparedStatement preparedStatement = conn.prepareStatement(sql); preparedStatement.setInt(1, 2); ResultSet resultSet = preparedStatement.executeQuery(); // ResultSet resultSet = statement.executeQuery(sql); while (resultSet.next()){ System.out.println(resultSet.getInt(1)); System.out.println(resultSet.getString(2)); System.out.println(resultSet.getString(3)); } } }
直接给你整懵!
statement与preparedment
个人总结:就是一个端茶送水的店小二。。。将sql语句提交给mysql;并将结果集拿回来。
preparedment是比较高级的店小二,会预编译,而且可以自定义查询值,不像statement每次sql语句都得拼接。
快就完事了preparedment
反正很复杂。
mybatis
简介
- 一款优秀的持久层框架。----------------------------就是数据库
- 避免几乎所有的JDBC代码和手动设置参数以及获取结果集的过程------------------------------就是全自动呗,不用再自己配statement和preparedment
- mybatis可以使用简单的XML或者注解来配置映射原生信息,将接口和Java的实力类相互映射。---------------------------------------数据库中有一个表叫作user,那么java中有一个类叫作user,字段间都相互对应。
- 以前叫作ibatis
- 现在再github上也有
持久化
数据可以保持很久,就是保存在磁盘中呗。
持久层
完成持久化工作的代码块------->dao(data access object) 数据访问对象
为什么需要mybatis
-
帮助存数据、取数据
- 传统太繁琐
- 半自动的ORM框架(Object Relationship Mapping)----->对象关系映射
优点:简单、灵活、解除sql语句与程序代码的耦合
简单的mybatis程序
mybatis的执行流程
实体类-----Lombok插件有问题,导不进去
package com.sicheng.entity; public class User { private int id; private String name; private String pwd; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getPwd() { return pwd; } public void setPwd(String pwd) { this.pwd = pwd; } public User(int id, String name, String pwd) { this.id = id; this.name = name; this.pwd = pwd; } public User() { } @Override public String toString() { return "User{" + "id=" + id + ", name='" + name + '\'' + ", pwd='" + pwd + '\'' + '}'; } }
查找类---也就是dao类
就是通过各种姿势查找访问数据库的类
例如:通过主键查找、名字查找、、、、、
package com.sicheng.dao; import com.sicheng.entity.User; import java.util.List; public interface UserMapper { List<User> selectUser(); }
Mybatis的配置文件
应该看的懂吧
<?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> <!-- 这里写配置内容 --> <environments default="mysql"> <environment id="mysql"> <transactionManager type="JDBC"></transactionManager> <dataSource type="POOLED"> <property name="driver" value="com.mysql.cj.jdbc.Driver"/> <property name="url" value="jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT%2B8"/> <property name="username" value="root"/> <property name="password" value="123456"/> </dataSource> </environment> </environments> <mappers> <mapper resource="com/sicheng/dao/userMapper.xml"/> </mappers> </configuration>
与dao类相互映射的,mapper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.sicheng.dao.UserMapper"> <select id="selectUser" resultType="com.sicheng.entity.User"> select * from user; </select> </mapper>
MybatisUtils
用于生产session
package com.sicheng.utils; 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.IOException; import java.io.InputStream; public class MybatisUtils { private static SqlSessionFactory sqlSessionFactory; static{ try { String resource = "mybatis-config.xml"; InputStream inputStream = null; inputStream = Resources.getResourceAsStream(resource); sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); } catch (IOException e) { e.printStackTrace(); } } public static SqlSession getSession(){ return sqlSessionFactory.openSession(); } }
Test
import com.sicheng.dao.UserMapper; import com.sicheng.entity.User; import com.sicheng.utils.MybatisUtils; import org.apache.ibatis.session.SqlSession; import org.junit.Test; import java.util.List; public class MybatisTest { @Test public void selectUser(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); List<User> users = userMapper.selectUser(); for (User user :users) { System.out.println(user); } } }
注意事项
- Mapper文件当中,一定要写namespace,指明这是哪个dao类的映射文件
- mapper文件中 id 一定是那个dao类的方法。
- UseMapper类 和 userMapper配置文件的名字必须保持也一样的哦!!!!!!
补充知识
xml中的 & 是个啥?
xml当中不能显示的符号 以及 如何进行转义
< | < | 小于号 |
> | > | 大于号 |
& | & | 和 |
&apos | ' | 单引号 |
" | " | 双引号 |
第二种方法:
<![CDATA[ 内部的所有内容都会被解析器忽略 ]]>
数据库连接中
jdbc:mysql://localhost:3306/test?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT%2B8
要写时间区间的,保证安全性?
Resources类
Resources 类为从类路径中加载资源,提供了易于使用的方法。
所以才在加载时,直接使用mybatis-config.xml这个路径名
Resources类的常用情况
- 从类路径下加载SQL Map配置文件
- 从类路径加载DAO Manager配置文件
- 从类路径机在各种.properties文件
Resources类加载一个资源的方式
- 对于简单的只读文本数据,加载为Reader
- 对于简单的只读二进制或者文本数据,加载为Stream;
- 对于读写二进制或文本文件,加载为File.
- 对于只读的配置文件,加载为Properties
- 对于只读的通用资源,加载为URL
根据加载方式不同,加载资源的方法如下
Reader getResoutceAsReader(String resource)
Stream getResourceAsStream(String resource)
File getResourceAsFile(String resource)
Properties getResourceAsProperties(String resource);
Url getResourceAsUrl(String resource)
继续各种操作吧
查询
通过主键ID查询
dao类
package com.sicheng.dao; import com.sicheng.entity.User; import java.util.List; public interface UserMapper { //猛查 List<User> selectUser(); //通过ID查 User selectUserById(int id); // //通过name、pwd查 // List<User> selectUserByNameAndPwd(String name, String pwd); // // //key模糊查询 // List<User> selectUserByLikeKey(String key); }
mapper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.sicheng.dao.UserMapper"> <select id="selectUser" resultType="com.sicheng.entity.User"> select * from user; </select> <select id="selectUserById" resultType="com.sicheng.entity.User" parameterType="int"> select * from user where id=#{id} </select> </mapper>
注意一下:
- 当只有一个,参数的时候,就都可以不用写;
- 接入,参数有两个,那写不写都会错的。
上面必错!!!!!
Test文件
import com.sicheng.dao.UserMapper; import com.sicheng.entity.User; import com.sicheng.utils.MybatisUtils; import org.apache.ibatis.session.SqlSession; import org.junit.Test; import java.util.List; public class MybatisTest { @Test public void selectUser(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); List<User> users = userMapper.selectUser(); for (User user :users) { System.out.println(user); } } @Test public void selectUserById(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); User user = userMapper.selectUserById(2); System.out.println(user); } }
通过name属性查询
主要是想测试下,当parameterType是复杂类型的,即对象的时候,不写会不会报错
发现并没有什么问题!!!!
dao类
package com.sicheng.dao; import com.sicheng.entity.User; import java.util.List; public interface UserMapper { //猛查 List<User> selectUser(); //通过ID查 User selectUserById(int id); //通过name属性查 List<User> selectUserByName(String name); }
mapper配置文件
<?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.sicheng.dao.UserMapper"> <select id="selectUser" resultType="com.sicheng.entity.User"> select * from user; </select> <select id="selectUserById" resultType="com.sicheng.entity.User" parameterType="int"> select * from user where id=#{id} </select> <select id="selectUserByName" resultType="com.sicheng.entity.User"> select * from user where name = #{name}; </select> </mapper>
test文件
import com.sicheng.dao.UserMapper; import com.sicheng.entity.User; import com.sicheng.utils.MybatisUtils; import org.apache.ibatis.session.SqlSession; import org.junit.Test; import java.util.List; public class MybatisTest { @Test public void selectUser(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); List<User> users = userMapper.selectUser(); for (User user :users) { System.out.println(user); } } @Test public void selectUserById(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); User user = userMapper.selectUserById(2); System.out.println(user); } @Test public void selectUserByName(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); List<User> users = userMapper.selectUserByName("张三"); for (User user : users) { System.out.println(user); } } }
通过根据密码、名字查询
这下传入两种参数,怎么办呢?
第一种方法
@Param(“mapper文件需要调用的名字”)
dao类
package com.sicheng.dao; import com.sicheng.entity.User; import org.apache.ibatis.annotations.Param; import java.util.List; public interface UserMapper { //猛查 List<User> selectUser(); //通过ID查 User selectUserById(int id); //通过name属性查 List<User> selectUserByName(String name); //通过name、pwd值进行查询 List<User> selectUserByNameAndPwd(@Param("name") String name, @Param("pwd") String pwd); }
mapper配置文件
<?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.sicheng.dao.UserMapper"> <select id="selectUser" resultType="com.sicheng.entity.User"> select * from user; </select> <select id="selectUserById" resultType="com.sicheng.entity.User" parameterType="int"> select * from user where id=#{id} </select> <select id="selectUserByName" resultType="com.sicheng.entity.User"> select * from user where name = #{name}; </select> <select id="selectUserByNameAndPwd" resultType="com.sicheng.entity.User"> select * from user where name = #{name} and pwd=#{pwd}; </select> </mapper>
test文件
import com.sicheng.dao.UserMapper; import com.sicheng.entity.User; import com.sicheng.utils.MybatisUtils; import org.apache.ibatis.session.SqlSession; import org.junit.Test; import java.util.List; public class MybatisTest { @Test public void selectUser(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); List<User> users = userMapper.selectUser(); for (User user :users) { System.out.println(user); } } @Test public void selectUserById(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); User user = userMapper.selectUserById(2); System.out.println(user); } @Test public void selectUserByName(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); List<User> users = userMapper.selectUserByName("张三"); for (User user : users) { System.out.println(user); } } @Test public void selectUserByNameAndPwd(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); List<User> users = userMapper.selectUserByNameAndPwd("张三", "abcde"); for (User user : users) { System.out.println(user); } } }
第二种方法
使用Map进行传输
dao类
package com.sicheng.dao; import com.sicheng.entity.User; import org.apache.ibatis.annotations.Param; import java.util.List; import java.util.Map; public interface UserMapper { //猛查 List<User> selectUser(); //通过ID查 User selectUserById(int id); //通过name属性查 List<User> selectUserByName(String name); //通过name、pwd值进行查询 List<User> selectUserByNameAndPwd(Map<String, String> map); }
mapper配置文件
<?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.sicheng.dao.UserMapper"> <select id="selectUser" resultType="com.sicheng.entity.User"> select * from user; </select> <select id="selectUserById" resultType="com.sicheng.entity.User" parameterType="int"> select * from user where id=#{id} </select> <select id="selectUserByName" resultType="com.sicheng.entity.User"> select * from user where name = #{name}; </select> <select id="selectUserByNameAndPwd" resultType="com.sicheng.entity.User" parameterType="map"> select * from user where name = #{name} and pwd=#{pwd}; </select> </mapper>
test文件
import com.sicheng.dao.UserMapper; import com.sicheng.entity.User; import com.sicheng.utils.MybatisUtils; import org.apache.ibatis.session.SqlSession; import org.junit.Test; import java.util.HashMap; import java.util.List; import java.util.Map; public class MybatisTest { @Test public void selectUser(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); List<User> users = userMapper.selectUser(); for (User user :users) { System.out.println(user); } } @Test public void selectUserById(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); User user = userMapper.selectUserById(2); System.out.println(user); } @Test public void selectUserByName(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); List<User> users = userMapper.selectUserByName("张三"); for (User user : users) { System.out.println(user); } } @Test public void selectUserByNameAndPwd(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); Map<String, String> map = new HashMap<String, String>(); map.put("name", "张三"); map.put("pwd", "abcde"); List<User> users = userMapper.selectUserByNameAndPwd(map); for (User user : users) { System.out.println(user); } } }
模糊查询
dao类
package com.sicheng.dao; import com.sicheng.entity.User; import java.util.List; import java.util.Map; public interface UserMapper { //猛查 List<User> selectUser(); //通过ID查 User selectUserById(int id); //通过name属性查 List<User> selectUserByName(String name); //通过name、pwd值进行查询 List<User> selectUserByNameAndPwd(Map<String, String> map); List<User> selectUserLikeName(String str); //插入 int insertUser(User user); //更新 int updateUser(User user); //删除 int deleteUser(User user); }
mapper配置文件
<?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.sicheng.dao.UserMapper"> <select id="selectUser" resultType="com.sicheng.entity.User"> select * from user; </select> <select id="selectUserById" resultType="com.sicheng.entity.User" parameterType="int"> select * from user where id=#{id} </select> <select id="selectUserByName" resultType="com.sicheng.entity.User"> select * from user where name = #{name}; </select> <select id="selectUserByNameAndPwd" resultType="com.sicheng.entity.User" parameterType="map"> select * from user where name = #{name} and pwd=#{pwd}; </select> <select id="selectUserLikeName" parameterType="String" resultType="com.sicheng.entity.User"> select * from user where name like "%"#{str}; </select> <insert id="insertUser" parameterType="com.sicheng.entity.User"> insert into user(id, name, pwd) value (#{id}, #{name}, #{pwd}); </insert> <update id="updateUser" parameterType="com.sicheng.entity.User"> update user set name=#{name},pwd=#{pwd} where id=#{id}; </update> <delete id="deleteUser" parameterType="com.sicheng.entity.User"> delete from user where id=#{id}; </delete> </mapper>
test文件
import com.sicheng.dao.UserMapper; import com.sicheng.entity.User; import com.sicheng.utils.MybatisUtils; import org.apache.ibatis.session.SqlSession; import org.junit.Test; import java.util.HashMap; import java.util.List; import java.util.Map; public class MybatisTest { @Test public void selectUser(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); List<User> users = userMapper.selectUser(); for (User user :users) { System.out.println(user); } } @Test public void selectUserById(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); User user = userMapper.selectUserById(2); System.out.println(user); } @Test public void selectUserByName(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); List<User> users = userMapper.selectUserByName("张三"); for (User user : users) { System.out.println(user); } } @Test public void selectUserByNameAndPwd(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); Map<String, String> map = new HashMap<String, String>(); map.put("name", "张三"); map.put("pwd", "abcde"); List<User> users = userMapper.selectUserByNameAndPwd(map); for (User user : users) { System.out.println(user); } } @Test public void selectUserLikeName(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); List<User> users = userMapper.selectUserLikeName("四"); for (User user :users) { System.out.println(user); } } @Test public void insertUser(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); int flag = userMapper.insertUser(new User(4, "李思成", "12345")); System.out.println(flag); session.commit(); } @Test public void updateUser(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); int flag = userMapper.updateUser(new User(4, "江GG", "12345")); System.out.println(flag); session.commit(); } @Test public void deleteUser(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); int flag = userMapper.deleteUser(new User(4, "江GG", "12345")); System.out.println(flag); session.commit(); } }
插入
没有resultType
并且记住session.commit。提交事务
dao类
package com.sicheng.dao; import com.sicheng.entity.User; import org.apache.ibatis.annotations.Param; import java.util.List; import java.util.Map; public interface UserMapper { //猛查 List<User> selectUser(); //通过ID查 User selectUserById(int id); //通过name属性查 List<User> selectUserByName(String name); //通过name、pwd值进行查询 List<User> selectUserByNameAndPwd(Map<String, String> map); //插入 int insertUser(User user); }
mapper配置文件
<?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.sicheng.dao.UserMapper"> <select id="selectUser" resultType="com.sicheng.entity.User"> select * from user; </select> <select id="selectUserById" resultType="com.sicheng.entity.User" parameterType="int"> select * from user where id=#{id} </select> <select id="selectUserByName" resultType="com.sicheng.entity.User"> select * from user where name = #{name}; </select> <select id="selectUserByNameAndPwd" resultType="com.sicheng.entity.User" parameterType="map"> select * from user where name = #{name} and pwd=#{pwd}; </select> <insert id="insertUser" parameterType="com.sicheng.entity.User"> insert into user(id, name, pwd) value (#{id}, #{name}, #{pwd}); </insert> </mapper>
test文件
import com.sicheng.dao.UserMapper; import com.sicheng.entity.User; import com.sicheng.utils.MybatisUtils; import org.apache.ibatis.session.SqlSession; import org.junit.Test; import java.util.HashMap; import java.util.List; import java.util.Map; public class MybatisTest { @Test public void selectUser(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); List<User> users = userMapper.selectUser(); for (User user :users) { System.out.println(user); } } @Test public void selectUserById(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); User user = userMapper.selectUserById(2); System.out.println(user); } @Test public void selectUserByName(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); List<User> users = userMapper.selectUserByName("张三"); for (User user : users) { System.out.println(user); } } @Test public void selectUserByNameAndPwd(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); Map<String, String> map = new HashMap<String, String>(); map.put("name", "张三"); map.put("pwd", "abcde"); List<User> users = userMapper.selectUserByNameAndPwd(map); for (User user : users) { System.out.println(user); } } @Test public void insertUser(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); int flag = userMapper.insertUser(new User(4, "李思成", "12345")); System.out.println(flag); session.commit(); } }
更新
记住一定要提交
dao类
package com.sicheng.dao; import com.sicheng.entity.User; import org.apache.ibatis.annotations.Param; import java.util.List; import java.util.Map; public interface UserMapper { //猛查 List<User> selectUser(); //通过ID查 User selectUserById(int id); //通过name属性查 List<User> selectUserByName(String name); //通过name、pwd值进行查询 List<User> selectUserByNameAndPwd(Map<String, String> map); //插入 int insertUser(User user); //更新 int updateUser(User user); }
mapper配置文件
<?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.sicheng.dao.UserMapper"> <select id="selectUser" resultType="com.sicheng.entity.User"> select * from user; </select> <select id="selectUserById" resultType="com.sicheng.entity.User" parameterType="int"> select * from user where id=#{id} </select> <select id="selectUserByName" resultType="com.sicheng.entity.User"> select * from user where name = #{name}; </select> <select id="selectUserByNameAndPwd" resultType="com.sicheng.entity.User" parameterType="map"> select * from user where name = #{name} and pwd=#{pwd}; </select> <insert id="insertUser" parameterType="com.sicheng.entity.User"> insert into user(id, name, pwd) value (#{id}, #{name}, #{pwd}); </insert> <update id="updateUser" parameterType="com.sicheng.entity.User"> update user set name=#{name},pwd=#{pwd} where id=#{id}; </update> </mapper>
test文件
import com.sicheng.dao.UserMapper; import com.sicheng.entity.User; import com.sicheng.utils.MybatisUtils; import org.apache.ibatis.session.SqlSession; import org.junit.Test; import java.util.HashMap; import java.util.List; import java.util.Map; public class MybatisTest { @Test public void selectUser(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); List<User> users = userMapper.selectUser(); for (User user :users) { System.out.println(user); } } @Test public void selectUserById(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); User user = userMapper.selectUserById(2); System.out.println(user); } @Test public void selectUserByName(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); List<User> users = userMapper.selectUserByName("张三"); for (User user : users) { System.out.println(user); } } @Test public void selectUserByNameAndPwd(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); Map<String, String> map = new HashMap<String, String>(); map.put("name", "张三"); map.put("pwd", "abcde"); List<User> users = userMapper.selectUserByNameAndPwd(map); for (User user : users) { System.out.println(user); } } @Test public void insertUser(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); int flag = userMapper.insertUser(new User(4, "李思成", "12345")); System.out.println(flag); session.commit(); } @Test public void updateUser(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); int flag = userMapper.updateUser(new User(4, "江GG", "12345")); System.out.println(flag); session.commit(); } }
删除
dao类
package com.sicheng.dao; import com.sicheng.entity.User; import org.apache.ibatis.annotations.Param; import java.util.List; import java.util.Map; public interface UserMapper { //猛查 List<User> selectUser(); //通过ID查 User selectUserById(int id); //通过name属性查 List<User> selectUserByName(String name); //通过name、pwd值进行查询 List<User> selectUserByNameAndPwd(Map<String, String> map); //插入 int insertUser(User user); //更新 int updateUser(User user); //删除 int deleteUser(User user); }
mapper配置文件
<?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.sicheng.dao.UserMapper"> <select id="selectUser" resultType="com.sicheng.entity.User"> select * from user; </select> <select id="selectUserById" resultType="com.sicheng.entity.User" parameterType="int"> select * from user where id=#{id} </select> <select id="selectUserByName" resultType="com.sicheng.entity.User"> select * from user where name = #{name}; </select> <select id="selectUserByNameAndPwd" resultType="com.sicheng.entity.User" parameterType="map"> select * from user where name = #{name} and pwd=#{pwd}; </select> <insert id="insertUser" parameterType="com.sicheng.entity.User"> insert into user(id, name, pwd) value (#{id}, #{name}, #{pwd}); </insert> <update id="updateUser" parameterType="com.sicheng.entity.User"> update user set name=#{name},pwd=#{pwd} where id=#{id}; </update> <delete id="deleteUser" parameterType="com.sicheng.entity.User"> delete from user where id=#{id}; </delete> </mapper>
test文件
import com.sicheng.dao.UserMapper; import com.sicheng.entity.User; import com.sicheng.utils.MybatisUtils; import org.apache.ibatis.session.SqlSession; import org.junit.Test; import java.util.HashMap; import java.util.List; import java.util.Map; public class MybatisTest { @Test public void selectUser(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); List<User> users = userMapper.selectUser(); for (User user :users) { System.out.println(user); } } @Test public void selectUserById(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); User user = userMapper.selectUserById(2); System.out.println(user); } @Test public void selectUserByName(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); List<User> users = userMapper.selectUserByName("张三"); for (User user : users) { System.out.println(user); } } @Test public void selectUserByNameAndPwd(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); Map<String, String> map = new HashMap<String, String>(); map.put("name", "张三"); map.put("pwd", "abcde"); List<User> users = userMapper.selectUserByNameAndPwd(map); for (User user : users) { System.out.println(user); } } @Test public void insertUser(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); int flag = userMapper.insertUser(new User(4, "李思成", "12345")); System.out.println(flag); session.commit(); } @Test public void updateUser(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); int flag = userMapper.updateUser(new User(4, "江GG", "12345")); System.out.println(flag); session.commit(); } @Test public void deleteUser(){ SqlSession session = MybatisUtils.getSession(); UserMapper userMapper = session.getMapper(UserMapper.class); int flag = userMapper.deleteUser(new User(4, "江GG", "12345")); System.out.println(flag); session.commit(); } }