今天完成的事情：

完成mybatis编写DAO

完成mybatis映射mapper

<?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>
    <!-- 和Spring整合后environment配置都会被干掉 -->
    <environments default="development">
        <environment id="development">
            <!-- 使用jdbc事务管理，目前由mybatis来管理 -->
            <transactionManager type="JDBC" />
            <!-- 数据库连接池，目前由mybatis来管理 -->
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver" />
                <property name="url" value="jdbc:mysql://localhost:3306/mydatabases" />
                <property name="username" value="root" />
                <property name="password" value="root" />
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="mybatis/Mapper.xml" />
        <mapper resource="mybatis/UserMapper.xml" />

    </mappers>
</configuration>

<?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="test">
    <!-- 需求：通过id查询用户 -->
    <select id="find" parameterType="int" resultType="mybatis.User">

        select * from student where ID = #{ID}
    </select>
</mapper>

package mybatis;

public interface UserMapper {
    //根据id查询用户信息
    public User findUserById(int id) throws Exception;
    //根据用户名模糊查询
//    public List<User> findUserByName(String name) throws Exception;
    //添加用户信息
//    public void insertUser(User user) throws Exception;
    //删除用户信息
//    public void deleteUser(int id) throws Exception;
    //更新用户信息
//    public void updateUser(User user) throws Exception;
}

<mapper namespace="mybatis.UserMapper">
    <!-- 需求：通过id查询用户 -->
    <select id="findUserById" parameterType="int" resultType="mybatis.User">

        select * from student where ID = #{ID}
    </select>
</mapper>

package mybatis;

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.junit.Before;
import org.junit.Test;

import java.io.InputStream;

public class MapperTest {
    private SqlSessionFactory sqlSessionFactory;
    
    @Before //创建sqlSessionFactory
    public void setUp() throws Exception {
        String resource = "SqlMapConfig.xml"; //mybatis配置文件
        //得到配置文件的流
        InputStream inputStream = Resources.getResourceAsStream(resource);
        //创建会话工厂SqlSessionFactory,要传入mybaits的配置文件的流
        sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
    }
    
    @Test
    public void testFindUserById() throws Exception {
        
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //创建UserMapper对象，mybatis自动生成mapper代理对象
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        User user = userMapper.findUserById(1);
        System.out.println(user);
    }
    
//    @Test
//    public void testFindUserByName() throws Exception {
//
//        SqlSession sqlSession = sqlSessionFactory.openSession();
//        //创建UserMapper对象，mybatis自动生成mapper代理对象
//        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
//        List<User> list = userMapper.findUserByName("倪升武");
//        sqlSession.close();
//        System.out.println(list);
//    }
}

package mybatis;

public class User {
    private int ID;
    private String create_at;
    private String update_at;
    private String name;
    private String dailyLink;
    private int QQ;
    private String onlineNumber;
    private String mail;
    private int phone;
    private String enrollmentTime;
    private String professionType;
    private String brotherName;
    private String promise;
    
    @Override
    public String toString() {
        return "student{" +
                "id=" + ID +
                ", name='" + name + '\'' +
                '}';
    }
    
    public Integer getId() {
        return ID;
    }
    public void setId(Integer ID) {
        this.ID = ID;
    }
    
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    
    public String getCreate_at() {
        return create_at;
    }
    public void setCreate_at(String create_at) {
        this.create_at = create_at;
    }
    
    public String getUpdate_at() {
        return update_at;
    }
    public void setUpdate_at(String update_at) {
        this.update_at = update_at;
    }
    
    public String getDailyLink() {
        return dailyLink;
    }
    public void setDailyLink(String dailyLink) {
        this.dailyLink = dailyLink;
    }
    
    public String getOnlineNumber() {
        return onlineNumber;
    }
    public void setOnlineNumber(String onlineNumber) {
        this.onlineNumber = onlineNumber;
    }
    
    public String getEnrollmentTime() {
        return enrollmentTime;
    }
    public void setEnrollmentTime(String enrollmentTime) {
        this.enrollmentTime = enrollmentTime;
    }
    
    public String getProfessionType() {
        return professionType;
    }
    public void setProfessionType(String professionType) {
        this.professionType = professionType;
    }
    
    public String getMail() {
        return mail;
    }
    public void setMail(String mail) {
        this.mail = mail;
    }
    
    public String getBrotherName() {
        return brotherName;
    }
    public void setBrotherName(String brotherName) {
        this.brotherName = brotherName;
    }
    
    public String getPromise() {
        return promise;
    }
    public void setPromise(String promise) {
        this.promise = promise;
    }
    
    public int getQQ() {
        return QQ;
    }
    public void setQQ(int QQ) {
        this.QQ = QQ;
    }
    
    public int getPhone() {
        return phone;
    }
    public void setPhone(int phone) {
        this.phone = phone;
    }
}

明天计划的事情：

小课堂分享

遇到的问题：

收获：

Mapped Statements collection does not contain value for xxx

1.mybatis的映射文件的命令空间与接口的全限定名不一致;

2有可能mybatis的映射文件名字与接口的类名字不一致;

3.还有一种情况就是接口声明的方法在映射文件里面没有。