发表于: 2017-06-22 23:09:37
5 960
今天完成的事情:
今天重新学习了一遍mybatis,因为25题需要mybatis连接池的知识
最后把学到的总结一下:
mybatis有以下几个文件
表结构文件
存放Set和Get方法
例如:
public class User {
private int id;
private String userName;
private int userAge;
private String userAddress;
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public int getUserAge() {
return userAge;
}
public void setUserAge(int userAge) {
this.userAge = userAge;
}
public String getUserAddress() {
return userAddress;
}
public void setUserAddress(String userAddress) {
this.userAddress = userAddress;
}
public String toString(){
return "id:"+id+" 名字:"+userName+" 地址:"+userAddress;
}
}
数据库操作方法的接口
例如:
import java.util.List;
public interface IUserOperation {
public User selectUserByID(int id);
public List selectUsers(String userName);
public void addUser(User user);
public void deleteUser(int id);
public void updateUser(User user);
public List<Article> getUserArticles(int id);
}
mybatis-config.xml文件
首先是开头
<?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">
然后是
<typeAliases>
<!--这里的alias是表数据文件所在位置的别名-->
<typeAlias alias="User" type="com.yihaomen.mybatis.model.User"/>
</typeAliases>
再然后就是数据库的用户名和密码驱动
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://127.0.0.1:3306/test" />
<property name="username" value="root"/>
<property name="password" value="123456"/>
</dataSource>
</environment>
</environments>
最后是
<mappers>
<!--sql命令配置文件所在位置-->
<mapper resource=
"com/yihaomen/mybatis/model/User.xml"/>
</mappers>
SQl命令配置文件
<?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.yihaomen.mybatis.inter.IUserOperation">
<select id="selectUserByID" parameterType="int" resultType="User">
select * from `user` where id = #{id}
</select>
<!-- 为了返回list 类型而定义的returnMap -->
<resultMap type="User" id="resultListUser">
<id column="id" property="id" />
<result column="userName" property="userName" />
<result column="userAge" property="userAge" />
<result column="userAddress" property="userAddress" />
</resultMap>
<!-- 返回list 的select 语句,注意 resultMap 的值是指向前面定义好的 -->
<select id="selectUsers" parameterType="string" resultMap="resultListUser">
select * from user where userName like #{userName}
</select>
<!--执行增加操作的SQL语句。id和parameterType
分别与IUserOperation接口中的addUser方法的名字和
参数类型一致。以#{name}的形式引用Student参数
的name属性,MyBatis将使用反射读取Student参数
的此属性。#{name}中name大小写敏感。引用其他
的gender等属性与此一致。seGeneratedKeys设置
为"true"表明要MyBatis获取由数据库自动生成的主
键;keyProperty="id"指定把获取到的主键值注入
到Student的id属性-->
<insert id="addUser" parameterType="User"
useGeneratedKeys="true" keyProperty="id">
insert into user(userName,userAge,userAddress)
values(#{userName},#{userAge},#{userAddress})
</insert>
<delete id="deleteUser" parameterType="int">
delete from user where id=#{id}
</delete>
<update id="updateUser" parameterType="User" >
update user set userName=#{userName},userAge=#{userAge},userAddress=#{userAddress} where id=#{id}
</update>
<!-- User 联合文章进行查询 方法之一的配置 (多对一的方式) -->
<resultMap id="resultUserArticleList" type="Article"><!--这里的type是Article类所在位置的别名-->
<id property="id" column="aid" />
<result property="title" column="title" />
<result property="content" column="content" />
<association property="user" javaType="User">
<id property="id" column="id" />
<result property="userName" column="userName" />
<result property="userAddress" column="userAddress" />
</association>
</resultMap>
<select id="getUserArticles" parameterType="int" resultMap="resultUserArticleList">
select user.id,user.userName,user.userAddress,article.id aid,article.title,article.content from user,article
where user.id=article.userid and user.id=#{id}
</select>
</mapper>
Test测试文件
public class Test {
private static SqlSessionFactory sqlSessionFactory;
private static Reader reader;
// 获取配置文件
static{
try{
reader = Resources.getResourceAsReader("mybatis-config.xml");
//根据名称获取配置文件
sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);
}catch(Exception e){
e.printStackTrace();
}
}
// 接口sqlSessionFactory
public static SqlSessionFactory getSession(){
return sqlSessionFactory;
}
// main方法
public static void main(String[] args) {
Test testUser=new Test();
//testUser.updateUser();
//testUser.getUserList("%");
//testUser.getUserArticles(1);
testUser.addUser();
}
// 获取
public void getUserList(String userName){
SqlSession session = sqlSessionFactory.openSession();
//sqlSessionFactory.openSession();
try {
IUserOperation userOperation=session.getMapper(IUserOperation.class);
List<User> users = userOperation.selectUsers(userName);
for(User user:users){
System.out.println(user.toString());
}
} finally {
session.close();
}
}
明天计划的事情:
虽然对mybatis更深入的了解了但是对mybatis连接池还是一头雾水
遇到的问题:
无
收获:
对mybatis的理解更透彻了
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