Mybaits一对多处理。 一对多：比如：一个老师拥有多个学生！对于老师而言，就是一对多的关系！上一节，多对一地址：点击访问数据库（和上一篇Mybatis多对一的处理一样）CREATE TABLE `teacher` ( `id` INT(10) NOT NULL, `name` VARCHAR(30) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=INNODB DEFAULT CHARSET=utf8; INSERT INTO teacher(`id`, `name`) VALUES (1, '庞老师'); CREATE TABLE `student` ( `id` INT(10) NOT NULL, `name` VARCHAR(30) DEFAULT NULL, `tid` INT(10) DEFAULT NULL, PRIMARY KEY (`id`), KEY `fktid` (`tid`), CONSTRAINT `fktid` FOREIGN KEY (`tid`) REFERENCES `teacher` (`id`) ) ENGINE=INNODB DEFAULT CHARSET=utf8; INSERT INTO `student` (`id`, `name`, `tid`) VALUES ('1', '小明', '1'); INSERT INTO `student` (`id`, `name`, `tid`) VALUES ('2', '小红', '1'); INSERT INTO `student` (`id`, `name`, `tid`) VALUES ('3', '小张', '1'); INSERT INTO `student` (`id`, `name`, `tid`) VALUES ('4', '小李', '1'); INSERT INTO `student` (`id`, `name`, `tid`) VALUES ('5', '小王', '1'); 实体类（省略了构造函数、Setter/Getter）//Teacher类 public class Teacher { private int id; private String name; //一个老师拥有多个学生 private List<Student> students; } //Student类 public class Student { private int id; private String name; private int tid; } TeacherMapper接口（interface）//获取指定老师下的所有学生以及老师的信息 Teacher getTeacher(@Param("tid") int id); Teacher getTeacher2(@Param("tid") int id); 按照查询嵌套处理<select id="getTeacher2" resultMap="TeacherStudent2"> select * from mybatis.teacher where id = #{tid} </select> <resultMap id="TeacherStudent2" type="Teacher"> <collection property="students" javaType="ArrayList" ofType="Student" select="getStudentByTeacherId" column="id"/> </resultMap> <select id="getStudentByTeacherId" resultType="Student"> select * from mybatis.student where tid = #{tid} </select> 按照结果嵌套处理<!--按结果嵌套查询--> <select id="getTeacher" resultMap="TeacherStudent"> select s.id sid,s.name sname,t.name tname,t.id tid from student s,teacher t where s.tid = t.id and t.id = #{tid} </select> <resultMap id="TeacherStudent" type="Teacher"> <result property="id" column="tid"/> <result property="name" column="tname"/> <!--复杂的属性 对象：association 集合：collection 集合中的泛型信息，使用ofType获取 --> <collection property="students" ofType="Student"> <result property="id" column="sid"/> <result property="name" column="sname"/> <result property="tid" column="tid"/> </collection> </resultMap> 测试类@Test public void getTeacher(){ SqlSession sqlSession = MybatisUtils.getSqlSession(); TeacherMapper mapper = sqlSession.getMapper(TeacherMapper.class); Teacher teacher = mapper.getTeacher(1); System.out.println(teacher); sqlSession.close(); } @Test public void getTeacher2(){ SqlSession sqlSession = MybatisUtils.getSqlSession(); TeacherMapper mapper = sqlSession.getMapper(TeacherMapper.class); Teacher teacher = mapper.getTeacher2(1); System.out.println(teacher); sqlSession.close(); }

Mybatis多对一处理。 多对一：多个学生对应一个老师对于学生而言，关联 多个学生，关联一个老师【多对一】对于老师而言， 一个老师，有很多学生【一对多】数据库CREATE TABLE `teacher` ( `id` INT(10) NOT NULL, `name` VARCHAR(30) DEFAULT NULL, PRIMARY KEY (`id`) ) ENGINE=INNODB DEFAULT CHARSET=utf8; INSERT INTO teacher(`id`, `name`) VALUES (1, '庞老师'); CREATE TABLE `student` ( `id` INT(10) NOT NULL, `name` VARCHAR(30) DEFAULT NULL, `tid` INT(10) DEFAULT NULL, PRIMARY KEY (`id`), KEY `fktid` (`tid`), CONSTRAINT `fktid` FOREIGN KEY (`tid`) REFERENCES `teacher` (`id`) ) ENGINE=INNODB DEFAULT CHARSET=utf8; INSERT INTO `student` (`id`, `name`, `tid`) VALUES ('1', '小明', '1'); INSERT INTO `student` (`id`, `name`, `tid`) VALUES ('2', '小红', '1'); INSERT INTO `student` (`id`, `name`, `tid`) VALUES ('3', '小张', '1'); INSERT INTO `student` (`id`, `name`, `tid`) VALUES ('4', '小李', '1'); INSERT INTO `student` (`id`, `name`, `tid`) VALUES ('5', '小王', '1'); Student类 （省略了构造函数、Setter/Getter）public class Student { private int id; private String name; //学生需要关联一个老师 private Teacher teacher; } Teacher类 （省略了构造函数、Setter/Getter）public class Teacher { private int id; private String name; } 测试环境搭建新建实体类Teacher，Student建立Mapper接口建立Mapper.xml文件【在Resources目录下需要一级一级建立文件夹】在核心配置中绑定注册我们的Mapper接口或者文件测试查询是否能成功StudentMapper接口（interface）//查询所有学生信息，以及对于的老师的信息 public List<Student> getStudent(); // public List<Student> getStudent2(); 按照查询嵌套处理思路：1.查询所有的学生信息2.根据查询出来的学生的tid，寻找对应的老师 子查询<select id="getStudent" resultMap="StudentTeacher"> select * from student </select> <resultMap id="StudentTeacher" type="Student"> <result property="id" column="id"/> <result property="name" column="name"/> <!--复杂的属性 对象：association 集合：collection --> <association property="teacher" column="tid" javaType="Teacher" select="getTeacher"/> </resultMap> <select id="getTeacher" resultType="Teacher"> select * from teacher where id = #{id} </select> 按照结果嵌套处理<!--按照结果处理--> <select id="getStudent2" resultMap="StudentTeacher2"> select s.id sid,s.name sname,t.name tname from student s,teacher t where s.tid = t.id; </select> <resultMap id="StudentTeacher2" type="Student"> <result property="id" column="sid"/> <result property="name" column="sname"/> <association property="teacher" javaType="Teacher"> <result property="name" column="tname"/> </association> </resultMap> 测试代码@Test public void getStudent(){ SqlSession sqlSession = MybatisUtils.getSqlSession(); StudentMapper mapper = sqlSession.getMapper(StudentMapper.class); List<Student> studentList = mapper.getStudent(); for (Student student : studentList) { System.out.println(student); } sqlSession.close(); } @Test public void getStudent2(){ SqlSession sqlSession = MybatisUtils.getSqlSession(); StudentMapper mapper = sqlSession.getMapper(StudentMapper.class); List<Student> studentList = mapper.getStudent2(); for (Student student : studentList) { System.out.println(student); } sqlSession.close(); } 多对一掌握了？那么可以下一课了，来看看一对多吧！点击访问

Maven+Mybatis入门问题-无法编译java目录下的xml文件 初学maven+Mybatis的时候，把Mapper.xml放到了dao包下，编译的时候target目录下不会编译在java项目中的xml。解决方法在pom.xml中加入<!-- build中配置resources，来防止我们资源导出失败的问题 --> <build> <resources> <resource> <directory>src/main/java</directory> <includes> <include>**/*.xml</include> <include>**/*.properties</include> </includes> </resource> </resources> </build> 最后clean一下，就行。Q&A我在自学的时候，加了这个也没用，试了很多方法。比如:xml删除中文注释，build中加入resources目录之类，都没用。最后关机睡觉，第二天打开就突然可以了。配置了buil的同学如果还没用，建议关闭idea重新打开试试。

搭建自己SSR（科学上网）教程 第一步：服务器国外（美国、香港）之类的都可以。第二步：安装1.第一条命令wget --no-check-certificate -O shadowsocks-all.sh https://raw.githubusercontent.com/teddysun/shadowsocks_install/master/shadowsocks-all.sh 2.上面的命令执行结束后，执行下面的命令chmod +x shadowsocks-all.sh 3.上面的命令执行结束后，执行下面的命令./shadowsocks-all.sh 2>&1| tee shadowsocks-all.log 4.执行上述命令会有相关输入提示操作；根据需要选择。不明白的话就直接选1或者直接默认回车；之后会提示你输入密码和端口，对应设置即可，或者直接使用默认的；由于 iPhone端的wingy目前只支持到cfb，所以加密方式选择aes-256-cfb也就是选择7；全部执行完成之后就会出现如下信息：StartingShadowsocks success Congratulations, Shadowsocks-Python server install completed! YourServer IP : 你的IP YourServerPort: 在第四步提示设置的端口号 YourPassword: 在第四步提示设置的密码 YourEncryptionMethod: aes-256-cfb Your QR Code: (ForShadowsocksWindows, OSX, Androidand iOS clients) ss://YWVzLTI1Ni1jZmI6emh1aTA4MTA0MTJaaaccuMjmmLjU1LjE5MTo4tdVg4 Your QR Code has been saved as a PNG file path: /root/shadowsocks_python_qr.png Welcome to visit: https://teddysun.com/486.html Enjoy it! 第三步：SSR小飞机Windows：https://github.com/shadowsocks/shadowsocks-windows/releasesMac：https://github.com/yangfeicheung/Shadowsocks-X/releasesAndroid：https://github.com/shadowsocks/shadowsocks-android/releasesiPhone：App Store上下载ShadowLink，这个要用国外appid才可以下载哦。国内的搜不到的，因为shadowrocket收费的参考文章：点击访问

canvas-nest.js-一个基于 html5 canvas 绘制的网页背景效果 canvas-nest.js一个基于 html5 canvas 绘制的网页背景效果。使用快捷使用将下面的代码插入到 和 之间.强烈建议在 标签上方. 例如下面的代码结构 ... ... ... <script type="text/javascript" src="dist/canvas-nest.js"></script> 配置color: 线条颜色, 默认: '0,0,0' ；三个数字分别为(R,G,B)，注意用,分割pointColor: 交点颜色, 默认: '0,0,0' ；三个数字分别为(R,G,B)，注意用,分割opacity: 线条透明度（0~1）, 默认: 0.5count: 线条的总数量, 默认: 150zIndex: 背景的z-index属性，css属性用于控制所在层的位置, 默认: -1Typecho使用在有主题的情况下，将代码添加至底部自定义内容即可<script type="text/javascript" color="255,20,147" opacity='0.8' zIndex="-1" count="500" src="https://cdn.bootcss.com/canvas-nest.js/2.0.4/canvas-nest.js"></script> 下载Github官网：canvas-nest.js外链CDN：cdn