mybatis入門程序
1. 導入jar包
2. 創建並配置SqlMapConfig.xml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>
<!--
屬性
<properties></properties>
全局參數設置
<settings></settings>
類型別名
<typeAliases></typeAliases>
類型處理器
<typeHandles></typeHandles>
對象工廠
<objectFactory></objectFactory>
插件
<plugins></plugins>
以上屬性在後邊會詳細講解到,現在我們就只需要關注一下下面的配置即可
如下所配置的就是使用這點東西。
environments(環境信息集合)
environment(單個環境信息)
transactionManager(事物)
dataSource(數據源)
environment
environments
mappers(映射器)
-->
<!-- 和Spring整合後environments配置將廢除 -->
<!-- 配置mybatis的環境信息 -->
<environments default="development">
<environment id="development">
<!-- 配置JDBC事務控制,由mybatis進行管理 -->
<transactionManager type="JDBC"></transactionManager>
<!-- 配置數據源,採用dbcp連接池 -->
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver" />
<property name="url" value="jdbc:mysql://localhost:3306/mybatis1?useUnicode=true&characterEncoding=utf8" />
<property name="username" value="root" />
<property name="password" value="root" />
</dataSource>
</environment>
</environments>
<!-- 加載mapper映射文件 -->
<mappers>
<mapper resource="sqlmap/UserMapper.xml"/>
</mappers>
</configuration>
3. 創建UserMapper.xml映射文件
4. 創建實體類
/*
* CREATE TABLE `user` (
`user_id` int(11) NOT NULL AUTO_INCREMENT,
`user_name` varchar(255) NOT NULL,
`user_birth` date DEFAULT NULL,
PRIMARY KEY (`user_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
*/
5. 根據用戶id查詢用戶
(1)UserMapper.xml文件配置
<!-- 通過select標籤執行數據庫查詢語句
- id屬性:標識映射文件(UserMapper.xml)中的SQL
將SQL語句封裝到mapperStatement對象中,故id稱爲statement的id
- parameterType屬性:指定輸入參數的類型
- #{}標識一個佔位符
- #{id}:id標識接收的輸入參數,參數名稱是id;如果輸入參數是簡單類型,#{}中參數名可以任意
- resultType屬性:指定輸出結果的類型
-->
<select id="selectUserById" parameterType="java.lang.Integer" resultType="com.wzw.day1.model.User">
SELECT * FROM `user` WHERE user_id = #{id}
</select>
(2)Dao層
/**
* 入門案例1
* 根據id查詢用戶信息
* @throws IOException
*/
@Test
public void test1() throws IOException {
//獲取mybatis配置文件
String resource = "SqlMapConfig.xml";
//獲取配置文件流
InputStream inputStream = Resources.getResourceAsStream(resource);
//創建SqlSessionFactory會話工廠
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
//通過工廠得到SqlSession
SqlSession sqlSession = sqlSessionFactory.openSession();
//通過SqlSession操作數據庫
//第一個參數:namespace+"."+id
//第二個參數:parameterType
//return:resulteType
User user = sqlSession.selectOne("rumen1.selectUserById", 1);
System.out.println(user);
//釋放資源
sqlSession.close();
}
6. 根據用戶名模糊查詢
(1)UserMapper.xml映射文件
<!-- 根據用戶名模糊查詢
- resultType屬性:指定單條記錄所映射的Java對象類型
- ${}:拼接字符串,將接收的輸入參數拼接在SQL中
可能引起SQL注入
- ${value}:如果接收的輸入參數是簡單類型,${}中只能使用value
-->
<select id="selectUserByName" parameterType="java.lang.String" resultType="com.wzw.day1.model.User">
SELECT * FROM `user` WHERE user_name like '%${value}%'
</select>
(2)Dao層
/**
* 入門案例2
* 根據用戶名模糊查詢用戶信息
* @throws IOException
*/
@Test
public void test2() throws IOException {
String resource = "SqlMapConfig.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession sqlSession = sqlSessionFactory.openSession();
List<User> list = sqlSession.selectList("rumen1.selectUserByName", "小明");
System.out.println(list);
sqlSession.close();
}
7. 添加用戶
(1)UserMapper.xml映射文件
<!-- 添加用戶
- parameterType屬性:指定輸入參數類型User
- #{}:指定User類屬性名,mybatis通過ognl獲取對象屬性值
-->
<insert id="insertUser" parameterType="com.wzw.day1.model.User">
<!-- 獲取自增主鍵
- SELECT LAST_INSERT_ID()
- keyProperty屬性:將查詢到的主鍵值設置到parameterType指定的對象屬性中
- order屬性:SELECT LAST_INSERT_ID()函數執行順序
- resultType屬性:輸出結果類型
-->
<selectKey keyProperty="user_id" order="AFTER" resultType="java.lang.Integer">
SELECT LAST_INSERT_ID()
</selectKey>
INSERT INTO `user`(user_name, user_birth) VALUE (#{user_name},#{user_birth})
</insert>
(2)Dao層
/**
* 入門案例3
* 添加用戶
* @throws IOException
*/
@Test
public void test3() throws IOException {
String resource = "SqlMapConfig.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession sqlSession = sqlSessionFactory.openSession();
User user = new User();
user.setUser_name("張三");
user.setUser_birth(new Date());
sqlSession.insert("rumen1.insertUser", user);
//獲取插入用戶id
System.out.println(user.getUser_id());
//提交事務
sqlSession.commit();
sqlSession.close();
}
8. 刪除用戶
(1)UserMapper.xml映射文件
<!-- 根據用戶id刪除 -->
<delete id="deleteUserById" parameterType="java.lang.Integer">
DELETE FROM `user` WHERE user_id = #{value}
</delete>
(2)Dao層
/**
* 入門案例4
* 根據用戶id刪除用戶
* @throws IOException
*/
@Test
public void test4() throws IOException {
String resource = "SqlMapConfig.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession sqlSession = sqlSessionFactory.openSession();
//刪除用戶
List<User> list = sqlSession.selectList("rumen1.selectUserByName2", "張三");
User user = list.get(0);
System.out.println(user);
sqlSession.delete("rumen1.deleteUserById", user.getUser_id());
//提交事務
sqlSession.commit();
sqlSession.close();
}
9. 更新用戶
(1)UserMapper.xml映射文件
<!-- 根據用戶id更新 -->
<update id="updateUserById" parameterType="com.wzw.day1.model.User">
UPDATE `user` SET user_name = #{user_name} WHERE user_id = #{user_id}
</update>
(2)Dao層
/**
* 入門案例5
* 根據用戶id更新用戶
* @throws IOException
*/
@Test
public void test5() throws IOException {
String resource = "SqlMapConfig.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession sqlSession = sqlSessionFactory.openSession();
//更新用戶
User user = new User();
user.setUser_id(4);
user.setUser_name("張三");
user.setUser_birth(new Date());
sqlSession.update("rumen1.updateUserById", user);
//提交事務
sqlSession.commit();
sqlSession.close();
}
mybatis的mapper接口(相當於dao接口)代理開發方法
<select id="selectUserById" parameterType="java.lang.Integer" resultType="com.wzw.day1.model.User">
SELECT * FROM `user` WHERE user_id = #{value}
</select>
public User selectUserById(Integer user_id) throws Exception;
1. UserMapper.java
public interface UserMapper {
//根據id查詢用戶
//<select id="selectUserById" parameterType="java.lang.Integer" resultType="com.wzw.day1.model.User">
public User selectUserById(Integer user_id) throws Exception;
//根據用戶名模糊查詢
//<select id="selectUserByName" parameterType="java.lang.String" resultType="com.wzw.day1.model.User">
public List<User> selectUserByName(String user_name) throws Exception;
//添加用戶
//<insert id="insertUser" parameterType="com.wzw.day1.model.User">
public void insertUser(User user) throws Exception;
//刪除用戶
//<delete id="deleteUserById" parameterType="java.lang.Integer">
public void deleteUserById(Integer user_id) throws Exception;
//更新用戶
//<update id="updateUserById" parameterType="com.wzw.day1.model.User">
public void updateUserById(User user) throws Exception;
}
2. 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">
<!-- namespace命名空間,作用就是對SQL進行分類化管理(SQL隔離)
注:使用mapper代理方法開發,namespace爲Mapper接口名稱
-->
<mapper namespace="com.wzw.day1.mapper.UserMapper">
<!-- 通過select標籤執行數據庫查詢語句 -->
<select id="selectUserById" parameterType="java.lang.Integer" resultType="com.wzw.day1.model.User">
SELECT * FROM `user` WHERE user_id = #{value}
</select>
<!-- 根據用戶名模糊查詢 -->
<select id="selectUserByName" parameterType="java.lang.String" resultType="com.wzw.day1.model.User">
SELECT * FROM `user` WHERE user_name like '%${value}%'
</select>
<!-- 根據用戶名查詢用戶 -->
<select id="selectUserByName2" parameterType="java.lang.String" resultType="com.wzw.day1.model.User">
SELECT * FROM `user` WHERE user_name = #{value}
</select>
<!-- 添加用戶 -->
<insert id="insertUser" parameterType="com.wzw.day1.model.User">
<!-- 獲取自增主鍵 -->
<selectKey keyProperty="user_id" order="AFTER" resultType="java.lang.Integer">
SELECT LAST_INSERT_ID()
</selectKey>
INSERT INTO `user`(user_name, user_birth) VALUE (#{user_name},#{user_birth})
</insert>
<!-- 根據用戶id刪除 -->
<delete id="deleteUserById" parameterType="java.lang.Integer">
DELETE FROM `user` WHERE user_id = #{value}
</delete>
<!-- 根據用戶id更新 -->
<update id="updateUserById" parameterType="com.wzw.day1.model.User">
UPDATE `user` SET user_name = #{user_name} WHERE user_id = #{user_id}
</update>
</mapper>
3. TestDemo1.java
public class TestDemo1 {
/**
* 根據用戶id查詢
* @throws Exception
*/
@Test
public void test1() throws Exception {
//獲取mybatis配置文件
String resource = "SqlMapConfig.xml";
//獲取配置文件流
InputStream inputStream = Resources.getResourceAsStream(resource);
//創建SqlSessionFactory會話工廠
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
//通過工廠得到SqlSession
SqlSession sqlSession = sqlSessionFactory.openSession();
//創建UserMapper對象,mybatis自動生成
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
User user = userMapper.selectUserById(1);
System.out.println(user);
//釋放資源
sqlSession.close();
}
/**
* 根據用戶名模糊查詢
* @throws Exception
*/
@Test
public void test2() throws Exception {
//獲取mybatis配置文件
String resource = "SqlMapConfig.xml";
//獲取配置文件流
InputStream inputStream = Resources.getResourceAsStream(resource);
//創建SqlSessionFactory會話工廠
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
//通過工廠得到SqlSession
SqlSession sqlSession = sqlSessionFactory.openSession();
//創建UserMapper對象,mybatis自動生成
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
List<User> list = mapper.selectUserByName("小");
System.out.println(list);
//釋放資源
sqlSession.close();
}
/**
* 添加用戶
* @throws Exception
*/
@Test
public void test3() throws Exception {
//獲取mybatis配置文件
String resource = "SqlMapConfig.xml";
//獲取配置文件流
InputStream inputStream = Resources.getResourceAsStream(resource);
//創建SqlSessionFactory會話工廠
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
//通過工廠得到SqlSession
SqlSession sqlSession = sqlSessionFactory.openSession();
User user = new User();
user.setUser_name("wzw");
user.setUser_birth(new Date());
//創建UserMapper對象,mybatis自動生成
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
mapper.insertUser(user);
//提交事務
sqlSession.commit();
//釋放資源
sqlSession.close();
}
/**
* 刪除用戶
* @throws Exception
*/
@Test
public void test4() throws Exception {
//獲取mybatis配置文件
String resource = "SqlMapConfig.xml";
//獲取配置文件流
InputStream inputStream = Resources.getResourceAsStream(resource);
//創建SqlSessionFactory會話工廠
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
//通過工廠得到SqlSession
SqlSession sqlSession = sqlSessionFactory.openSession();
//創建UserMapper對象,mybatis自動生成
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
mapper.deleteUserById(8);
//提交事務
sqlSession.commit();
//釋放資源
sqlSession.close();
}
/**
* 更新用戶
* @throws Exception
*/
@Test
public void test5() throws Exception {
//獲取mybatis配置文件
String resource = "SqlMapConfig.xml";
//獲取配置文件流
InputStream inputStream = Resources.getResourceAsStream(resource);
//創建SqlSessionFactory會話工廠
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
//通過工廠得到SqlSession
SqlSession sqlSession = sqlSessionFactory.openSession();
//創建UserMapper對象,mybatis自動生成
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
User user = mapper.selectUserById(6);
user.setUser_name("測試1");
mapper.updateUserById(user);
//提交事務
sqlSession.commit();
//釋放資源
sqlSession.close();
}
}
mybatis配置文件SqlMapConfig.xml
<!--
屬性
<properties></properties>
全局參數設置
<settings></settings>
類型別名
<typeAliases></typeAliases>
類型處理器
<typeHandles></typeHandles>
對象工廠
<objectFactory></objectFactory>
插件
<plugins></plugins>
以上屬性在後邊會詳細講解到,現在我們就只需要關注一下下面的配置即可
如下所配置的就是使用這點東西。
environments(環境信息集合)
environment(單個環境信息)
transactionManager(事物)
dataSource(數據源)
environment
environments
mappers(映射器)
-->
properties(加載屬性文件)
<!-- 加載屬性文件 -->
<properties resource="db.properties"></properties>
settings(全局參數設置):
開啓二級緩存,開啓延遲加載
typeAliases(類型別名)
<!-- 設置別名 -->
<typeAliases>
<!-- 針對單個對象定義 -->
<!-- <typeAlias type="com.wzw.day1.model.User" alias="user"/> -->
<!-- 批量定義 (mybatis自動掃描包下類,定義別名,別名爲類名)-->
<package name="com.wzw.day1.model"/>
</typeAliases>
typeHandlers(類型處理器)
environments(環境)
<!-- 和Spring整合後environments配置將廢除 -->
<!-- 配置mybatis的環境信息 -->
<environments default="development">
<environment id="development">
<!-- 配置JDBC事務控制,由mybatis進行管理 -->
<transactionManager type="JDBC"></transactionManager>
<!-- 配置數據源,採用dbcp連接池 -->
<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>
mapper(映射配置)
<!-- 加載mapper映射文件 -->
<mappers>
<!-- mapper標籤resource屬性:一次加載一個映射文件 -->
<mapper resource="sqlmap/User.xml"/>
<!-- <mapper resource="mapper/UserMapper.xml"/> -->
<!-- mapper標籤class屬性:通過mapper接口加載映射文件
規範:mapper接口名與mapper.xml文件名保持一致,且在同一目錄下
-->
<!-- <mapper class="com.wzw.day1.mapper.UserMapper"/> -->
<!-- 批量加載mapper
指定mapper接口包名,mybatis自動掃描包下所有的mapper接口
規範:mapper接口名與mapper.xml文件名保持一致,且在同一目錄下
-->
<package name="com.wzw.day1.mapper"/>
</mappers>