mybatis连接mysql数据库对数据增，删，改以及查询所有

mybatis对数据库的数据的操作

 

实体类

private int id;
private  String name;
private int age;

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 int getAge() {
    return age;
}
public void setAge(int age) {
    this.age = age;
}




dao层的接口

public interface IUserInfoDAO {

/**
 * 查询所有
 * @return
 * @throws Exception
 */
public List<UserInfo> getAll();

/**
 * 新增用户
 * @param user
 * @return
 */
public int addSession(UserInfo user) throws Exception;

/**
 * 修改
 * @param id
 * @return
 */
public  int updateUser(int id);

/**
 * 删除
 * @param id
 * @return
 */
public  int delUser(int id);

}

xml文件（小配置文件）

<mapper namespace="cn.happy.dao.IUserInfoDAO">  这个是小配置文件必不可少的

<select id="getAll" parameterType="int" resultType="cn.happy.entity.UserInfo" useCache="true">
    select * from userinfo
</select>

<insert id="addSession">
   insert  into userinfo(name,age) value(#{name},#{age})
</insert>

<update id="updateUser" >
    UPDATE userinfo SET NAME=#{name} WHERE  id=#{id}
</update>

<delete id="delUser">
    delete from userInfo where id=#{id}
</delete>

</mapper>


测试类

/**
 * 查询所有
 */
@org.junit.Test
public void getAll(){
    SqlSession session = MyBatisUtil.getSession();
    IUserInfoDAO mapper = session.getMapper(IUserInfoDAO.class);
    List<UserInfo> all = mapper.getAll();
    for (UserInfo item : all) {
        System.out.println("编号："+item.getId()+"姓名："+item.getName()+"年龄："+item.getAge());
    }
    session.close();

}

/**
 * 删除
 */
@org.junit.Test
public void delUser() throws Exception{
    String resource = "mybatis-config.xml";
    InputStream inputStream = Resources.getResourceAsStream(resource);
    //获得会话工厂
    SqlSessionFactory sf = new SqlSessionFactoryBuilder().build(inputStream);
    SqlSession session = sf.openSession();
    int count = session.delete("cn.happy.dao.IUserInfoDAO.delUser",3);
    System.out.println(count);
    session.commit();
    session.close();
}
/**
 * 修改
 */
@org.junit.Test
public void updateUser() throws Exception{
    String resource = "mybatis-config.xml";
    InputStream inputStream = Resources.getResourceAsStream(resource);
    //获得会话工厂
    SqlSessionFactory sf = new SqlSessionFactoryBuilder().build(inputStream);

    SqlSession session = sf.openSession();
    UserInfo userInfo=new UserInfo();
    userInfo.setName("Hello");
    userInfo.setId(3);
    int count = session.update("cn.happy.dao.IUserInfoDAO.updateUser",userInfo);
    System.out.println(count);
    session.commit();
    session.close();
}


/**
 * 新增
 * @throws Exception
 */
public void inserts() throws Exception{
    String resource = "mybatis-config.xml";
    InputStream inputStream = Resources.getResourceAsStream(resource);
    //获得会话工厂
    SqlSessionFactory sf = new SqlSessionFactoryBuilder().build(inputStream);

    SqlSession session = sf.openSession();
    UserInfo userInfo=new UserInfo();
    userInfo.setName("晓华");
    userInfo.setAge(25);
    int count = session.insert("cn.happy.dao.IUserInfoDAO.addSession",userInfo);
    System.out.println(count);
    session.commit();
    session.close();
}



大配置文件

<configuration>
    <environments default="development">
        <environment id="development">

            <!-- 事务管理方案 -->
            <!--事务分类：
              编程式事务：  xx.commit() 即需要手动编写
              配置式事务：

              JDBC与MANAGED 区别
            -->
            <transactionManager type="JDBC" />
            <!--
               POOLED：连接池
               UNPOOLED：非连接池
               JNDI：Java Naming ANd Directory Interface  java命名和目录接口
            -->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver" />
                <property name="url" value="jdbc:mysql://localhost:3306/test"/>
                <property name="username" value="root" />
                <property name="password" value="123156" />
            </dataSource>
        </environment>
        <!--该内容在一个xml中可以有多个-->
        <!--<environment id="development">
            <transactionManager type="JDBC" />
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver" />
                <property name="url" value="jdbc:mysql://localhost:3306/test"/>
                <property name="username" value="root" />
                <property name="password" value="123156" />
            </dataSource>
        </environment>-->
    </environments>
    <!--映射文件：描述某个实体和数据库表的对应关系 -->
    <mappers>
       <mapper resource="cn/happy/dao/IUserInfoDAO.xml" />
      </mappers>
  </configuration>

即便有了上面的一系列配置，但是也不法访问到数据库
必须要有数据的依赖

 <!-- log4-->
 <dependency>
     <groupId>log4j</groupId>
     <artifactId>log4j</artifactId>
     <version>1.2.17</version>
 </dependency>

 <!-- mysql数据库 -->
 <dependency>
     <groupId>mysql</groupId>
     <artifactId>mysql-connector-java</artifactId>
     <version>5.1.39</version>
</dependency>