07—mybatis注解配置一
常用注解
Select:映射查询的sql语句。
SelectProvider:Select语句的动态sql映射。允许指定一个类名和一个方法在执行时返回运行的查询语句。有两个属性:type和mehtod,type属性是类的完全限定名,method是该类中的那个方法名。
Insert:映射插入的sql语句。
InsertProvider:Insert语句的动态sql映射。允许指定一个类名和一个方法在执行时返回运行的插入语句。有两个属性:type和method,typet属性是类的完全限定名,method是该类中的那个方法名。
Update:映射更新的sql语句。
UpdateProvider:Update语句的动态sql映射,允许指定一个类名和一个方法在执行时返回运行的更新语句。有两个属性:type和method,type属性是类的完全限定名,method是该类中的那个方法名。
Delete:映射删除的sql语句。
DeleteProvider:Delete语句的动态sql映射。允许指定一个类名和一个方法在执行时返回运行的删除语句。有两个属性:type和method,type属性是类的完全限定名,method是该类中的那个方法名。
Results:多个结果映射(Result)列表。
Options:提供配置选项的附加值,它们通常在映射语句上作为附加功能配置出现。
One:复杂类型的单独属性值映射。必须指定Select属性,表示已对一。
一对一
1.创建表
CREATE TABLE tb_card( id INT PRIMARY KEY AUTO_INCREMENT, CODE VARCHAR(18) ); INSERT INTO tb_card(CODE) VALUES('150801198009191038'); CREATE TABLE tb_person( id INT PRIMARY KEY AUTO_INCREMENT, NAME VARCHAR(18), sex VARCHAR(18), age INT, card_id INT UNIQUE, FOREIGN KEY (card_id) REFERENCES tb_card(id) ); INSERT INTO tb_person(NAME,sex,age,card_id) VALUES('mingming','男',28,1)
2.创建model
Card.java
package org.fkit.domain; import java.io.Serializable; public class Card implements Serializable { private Integer id; // 主键id private String code; // 身份证编号 public Card() { super(); } public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getCode() { return code; } public void setCode(String code) { this.code = code; } @Override public String toString() { return "Card [id=" + id + ", code=" + code + "]"; } }
package org.fkit.domain; import java.io.Serializable; public class Person implements Serializable { private Integer id; // 主键id private String name; // 姓名 private String sex; // 性别 private Integer age; // 年龄 // 人和身份证是一对一的关系,即一个人只有一个身份证 private Card card; public Person() { super(); // TODO Auto-generated constructor stub } 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 getSex() { return sex; } public void setSex(String sex) { this.sex = sex; } public Integer getAge() { return age; } public void setAge(Integer age) { this.age = age; } public Card getCard() { return card; } public void setCard(Card card) { this.card = card; } @Override public String toString() { return "Person [id=" + id + ", name=" + name + ", sex=" + sex + ", age=" + age + "]"; } }
3.mapper
CardMapper.java
package org.fkit.mapper; import org.apache.ibatis.annotations.Select; import org.fkit.domain.Card; public interface CardMapper { @Select("SELECT * FROM TB_CARD WHERE ID = #{id} ") Card selectCardById(Integer id); }
PersonMapper.java
package org.fkit.mapper; import org.apache.ibatis.annotations.One; import org.apache.ibatis.annotations.Result; import org.apache.ibatis.annotations.Results; import org.apache.ibatis.annotations.Select; import org.apache.ibatis.mapping.FetchType; import org.fkit.domain.Person; public interface PersonMapper { @Select("SELECT * FROM TB_PERSON WHERE ID = #{id}") @Results({ @Result(id=true,column="id",property="id"), @Result(column="name",property="name"), @Result(column="sex",property="sex"), @Result(column="age",property="age"), @Result(column="card_id",property="card", one=@One( select="org.fkit.mapper.CardMapper.selectCardById", fetchType=FetchType.EAGER)) }) Person selectPersonById(Integer id); }
4.mybatis-config.xml
db.properties
driver=com.mysql.jdbc.Driver url=jdbc:mysql://127.0.0.1:3306/mybatis username=root password=123456
log4j.properties
# Global logging configuration log4j.rootLogger=ERROR, stdout # MyBatis logging configuration... log4j.logger.org.fkit.mapper.PersonMapper=DEBUG log4j.logger.org.fkit.mapper.CardMapper=DEBUG # Console output... log4j.appender.stdout=org.apache.log4j.ConsoleAppender log4j.appender.stdout.layout=org.apache.log4j.PatternLayout log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n
mybatis-config.xml
<?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"> <!-- XML 配置文件包含对 MyBatis 系统的核心设置 --> <configuration> <properties resource="db.properties"/> <!-- 指定 MyBatis 所用日志的具体实现 --> <settings> <setting name="logImpl" value="LOG4J"/> </settings> <environments default="mysql"> <!-- 环境配置,即连接的数据库。 --> <environment id="mysql"> <!-- 指定事务管理类型,type="JDBC"指直接简单使用了JDBC的提交和回滚设置 --> <transactionManager type="JDBC"/> <!-- dataSource指数据源配置,POOLED是JDBC连接对象的数据源连接池的实现。 --> <dataSource type="POOLED"> <property name="driver" value="${driver}"/> <property name="url" value="${url}"/> <property name="username" value="${username}"/> <property name="password" value="${password}"/> </dataSource> </environment> </environments> <!-- mappers告诉了MyBatis去哪里找持久化类的映射文件 --> <mappers> <mapper class="org.fkit.mapper.PersonMapper"/> <mapper class="org.fkit.mapper.CardMapper"/> </mappers> </configuration>
5测试
package org.fkit.factory; import java.io.InputStream; import org.apache.ibatis.io.Resources; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder; public class FKSqlSessionFactory { private static SqlSessionFactory sqlSessionFactory = null; // 初始化创建SqlSessionFactory对象 static{ try { // 读取mybatis-config.xml文件 InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml"); sqlSessionFactory = new SqlSessionFactoryBuilder() .build(inputStream); } catch (Exception e) { e.printStackTrace(); } } // 获取SqlSession对象的静态方法 public static SqlSession getSqlSession(){ return sqlSessionFactory.openSession(); } // 获取SqlSessionFactory的静态方法 public static SqlSessionFactory getSqlSessionFactory() { return sqlSessionFactory; } }
OneToOneTest.java
package org.fkit.test; import org.apache.ibatis.session.SqlSession; import org.fkit.domain.Person; import org.fkit.factory.FKSqlSessionFactory; import org.fkit.mapper.PersonMapper; public class OneToOneTest { public static void main(String[] args) throws Exception { // 获取Session实例 SqlSession session = FKSqlSessionFactory.getSqlSession(); // 获取PersonMapper实例 PersonMapper pm = session.getMapper(PersonMapper.class); // 根据id查询Person对象,同时需要获得关联的Card对象 Person p = pm.selectPersonById(1); // 查看查询到的Person对象 System.out.println(p); // 查看查询到的关联的Card对象 System.out.println(p.getCard()); // 提交事务 session.commit(); // 关闭Session session.close(); } }
结果
DEBUG [main] - ==> Preparing: SELECT * FROM TB_PERSON WHERE ID = ? DEBUG [main] - ==> Parameters: 1(Integer) DEBUG [main] - ====> Preparing: SELECT * FROM TB_CARD WHERE ID = ? DEBUG [main] - ====> Parameters: 1(Integer) DEBUG [main] - <==== Total: 1 DEBUG [main] - <== Total: 1 Person [id=1, name=mingming, sex=男, age=28] Card [id=1, code=150801198009191038]
一对多
1.创建表
创建表tb_clazz
CREATE TABLE tb_clazz( id INT PRIMARY KEY AUTO_INCREMENT, CODE VARCHAR(18), NAME VARCHAR(18) ); INSERT INTO tb_clazz(CODE,NAME) VALUES('2017001','Java双语幼儿园中班');
CREATE TABLE tb_student( id INT PRIMARY KEY AUTO_INCREMENT, NAME VARCHAR(18), sex VARCHAR(18), age INT, clazz_id INT, FOREIGN KEY (clazz_id) REFERENCES tb_clazz(id) ); INSERT INTO tb_student(NAME,sex,age,clazz_id) VALUES('aa','男',23,1); INSERT INTO tb_student(NAME,sex,age,clazz_id) VALUES('bb','女',18,1); INSERT INTO tb_student(NAME,sex,age,clazz_id) VALUES('cc','男',21,1); INSERT INTO tb_student(NAME,sex,age,clazz_id) VALUES('dd','女',20,1);
2.创建model
Clazz.java
package org.fkit.domain; import java.io.Serializable; import java.util.List; public class Clazz implements Serializable { private Integer id; // 班级id,主键 private String code; // 班级编号 private String name; // 班级名称 // 班级和学生是一对多的关系,即一个班级可以有多个学生 private List<Student> students; public Clazz() { super(); // TODO Auto-generated constructor stub } public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getCode() { return code; } public void setCode(String code) { this.code = code; } public String getName() { return name; } public void setName(String name) { this.name = name; } public List<Student> getStudents() { return students; } public void setStudents(List<Student> students) { this.students = students; } @Override public String toString() { return "Clazz [id=" + id + ", code=" + code + ", name=" + name + "]"; } }
Student.java
package org.fkit.domain; import java.io.Serializable; public class Student implements Serializable { private Integer id; // 学生id,主键 private String name; // 姓名 private String sex; // 性别 private Integer age; // 年龄 // 学生和班级是多对一的关系,即一个学生只属于一个班级 private Clazz clazz; public Student() { super(); // TODO Auto-generated constructor stub } 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 getSex() { return sex; } public void setSex(String sex) { this.sex = sex; } public Integer getAge() { return age; } public void setAge(Integer age) { this.age = age; } public Clazz getClazz() { return clazz; } public void setClazz(Clazz clazz) { this.clazz = clazz; } @Override public String toString() { return "Student [id=" + id + ", name=" + name + ", sex=" + sex + ", age=" + age + "]"; } }
3.mapper
ClazzMapper.java
package org.fkit.mapper; import org.apache.ibatis.annotations.Many; import org.apache.ibatis.annotations.Result; import org.apache.ibatis.annotations.Results; import org.apache.ibatis.annotations.Select; import org.apache.ibatis.mapping.FetchType; import org.fkit.domain.Clazz; public interface ClazzMapper { // 根据id查询班级信息 @Select("SELECT * FROM TB_CLAZZ WHERE ID = #{id}") @Results({ @Result(id=true,column="id",property="id"), @Result(column="code",property="code"), @Result(column="name",property="name"), @Result(column="id",property="students", many=@Many( select="org.fkit.mapper.StudentMapper.selectByClazzId", fetchType=FetchType.LAZY)) }) Clazz selectById(Integer id); }
StudentMapper.java
package org.fkit.mapper; import java.util.List; import org.apache.ibatis.annotations.Result; import org.apache.ibatis.annotations.Results; import org.apache.ibatis.annotations.Select; import org.fkit.domain.Student; public interface StudentMapper { // 根据班级id查询班级所有学生 @Select("SELECT * FROM TB_STUDENT WHERE CLAZZ_ID = #{id}") @Results({ @Result(id=true,column="id",property="id"), @Result(column="name",property="name"), @Result(column="sex",property="sex"), @Result(column="age",property="age") }) List<Student> selectByClazzId(Integer clazz_id); }
4.mybatis-config.xml
db.properties
driver=com.mysql.jdbc.Driver url=jdbc:mysql://127.0.0.1:3306/mytestdb username=root password=root
log4j.properties
# Global logging configuration log4j.rootLogger=ERROR, stdout # MyBatis logging configuration... log4j.logger.org.fkit.mapper.ClazzMapper=DEBUG log4j.logger.org.fkit.mapper.StudentMapper=DEBUG # Console output... log4j.appender.stdout=org.apache.log4j.ConsoleAppender log4j.appender.stdout.layout=org.apache.log4j.PatternLayout log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n
mybatis-config.xml
<?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"> <!-- XML 配置文件包含对 MyBatis 系统的核心设置 --> <configuration> <properties resource="db.properties"/> <!-- 指定 MyBatis 所用日志的具体实现 --> <settings> <setting name="logImpl" value="LOG4J"/> <!-- 要使延迟加载生效必须配置下面两个属性 --> <setting name="lazyLoadingEnabled" value="true"/> <setting name="aggressiveLazyLoading" value="false"/> </settings> <environments default="mysql"> <!-- 环境配置,即连接的数据库。 --> <environment id="mysql"> <!-- 指定事务管理类型,type="JDBC"指直接简单使用了JDBC的提交和回滚设置 --> <transactionManager type="JDBC"/> <!-- dataSource指数据源配置,POOLED是JDBC连接对象的数据源连接池的实现。 --> <dataSource type="POOLED"> <property name="driver" value="${driver}"/> <property name="url" value="${url}"/> <property name="username" value="${username}"/> <property name="password" value="${password}"/> </dataSource> </environment> </environments> <!-- mappers告诉了MyBatis去哪里找持久化类的映射文件 --> <mappers> <mapper class="org.fkit.mapper.ClazzMapper"/> <mapper class="org.fkit.mapper.StudentMapper"/> </mappers> </configuration>
5.测试
FKSqlSessionFactory.java
package org.fkit.factory; import java.io.InputStream; import org.apache.ibatis.io.Resources; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder; public class FKSqlSessionFactory { private static SqlSessionFactory sqlSessionFactory = null; // 初始化创建SqlSessionFactory对象 static{ try { // 读取mybatis-config.xml文件 InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml"); sqlSessionFactory = new SqlSessionFactoryBuilder() .build(inputStream); } catch (Exception e) { e.printStackTrace(); } } // 获取SqlSession对象的静态方法 public static SqlSession getSqlSession(){ return sqlSessionFactory.openSession(); } // 获取SqlSessionFactory的静态方法 public static SqlSessionFactory getSqlSessionFactory() { return sqlSessionFactory; } }
结果:
DEBUG [main] - ==> Preparing: SELECT * FROM TB_CLAZZ WHERE ID = ? DEBUG [main] - ==> Parameters: 1(Integer) DEBUG [main] - <== Total: 1 1 2017001 Java双语幼儿园中班 DEBUG [main] - ==> Preparing: SELECT * FROM TB_STUDENT WHERE CLAZZ_ID = ? DEBUG [main] - ==> Parameters: 1(Integer) DEBUG [main] - <== Total: 4 Student [id=1, name=jack, sex=男, age=23] Student [id=2, name=rose, sex=女, age=18] Student [id=3, name=tom, sex=男, age=21] Student [id=4, name=alice, sex=女, age=20]
多对多
1.创建表
CREATE TABLE `t_student` ( `id` int(11) NOT NULL AUTO_INCREMENT, `student_name` varchar(20) DEFAULT NULL, PRIMARY KEY (`id`) ) INSERT INTO t_student (student_name)VALUES ('小米'); INSERT INTO t_student (student_name)VALUES ('小王'); INSERT INTO t_student (student_name)VALUES ('小李'); CREATE TABLE `t_courses` ( `id` int(11) NOT NULL AUTO_INCREMENT, `courses_name` varchar(20) DEFAULT NULL, PRIMARY KEY (`id`) ) INSERT INTO t_courses (courses_name)VALUES ('java'); INSERT INTO t_courses (courses_name)VALUES ('c#'); INSERT INTO t_courses (courses_name)VALUES ('php'); INSERT INTO t_courses (courses_name)VALUES ('vb'); INSERT INTO t_courses (courses_name)VALUES ('javascript'); CREATE TABLE `t_stu_cou` ( `id` int(11) NOT NULL AUTO_INCREMENT, `stu_id` int(11) DEFAULT NULL, `cou_id` int(11) DEFAULT NULL, PRIMARY KEY (`id`), KEY `stu_id` (`stu_id`), KEY `cou_id` (`cou_id`), CONSTRAINT `t_stu_cou_ibfk_1` FOREIGN KEY (`stu_id`) REFERENCES `t_student` (`id`), CONSTRAINT `t_stu_cou_ibfk_2` FOREIGN KEY (`cou_id`) REFERENCES `t_courses` (`id`) ) INSERT INTO t_stu_cou (stu_id,cou_id)VALUES (1,1); INSERT INTO t_stu_cou (stu_id,cou_id)VALUES (1,2); INSERT INTO t_stu_cou (stu_id,cou_id)VALUES (1,3); INSERT INTO t_stu_cou (stu_id,cou_id)VALUES (2,2); INSERT INTO t_stu_cou (stu_id,cou_id)VALUES (2,3); INSERT INTO t_stu_cou (stu_id,cou_id)VALUES (2,4);
2.创建model
CoursesBean.java
package org.fkit.domain; import java.io.Serializable; import java.util.List; public class CoursesBean implements Serializable{ private static final long serialVersionUID = 1L; private Integer id; private String name; // 使用 List<StudentBean>集合,是说明学习这门课程的所有学生 private List<StudentBean> student; public CoursesBean() { super(); } public CoursesBean(Integer id, String name, List<StudentBean> student) { super(); this.id = id; this.name = name; this.student = student; } 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 List<StudentBean> getStudent() { return student; } public void setStudent(List<StudentBean> student) { this.student = student; } @Override public String toString() { return "CoursesBean [id=" + id + ", name=" + name + ", student=" + student + "]"; } }
StudentBean.java
package org.fkit.domain; import java.io.Serializable; import java.util.List; public class StudentBean implements Serializable{ private static final long serialVersionUID = 1L; private Integer id; private String name; private List<CoursesBean> courses; public StudentBean() { super(); } public StudentBean(Integer id, String name, List<CoursesBean> courses) { super(); this.id = id; this.name = name; this.courses = courses; } 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 List<CoursesBean> getCourses() { return courses; } public void setCourses(List<CoursesBean> courses) { this.courses = courses; } @Override public String toString() { return "StudentBean [id=" + id + ", name=" + name + ", courses=" + courses + "]"; } }
3.mapper
CoursesMapper.java
package org.fkit.mapper; import org.apache.ibatis.annotations.Result; import org.apache.ibatis.annotations.Results; import org.apache.ibatis.annotations.Select; import org.apache.ibatis.mapping.FetchType; import org.fkit.domain.CoursesBean; import org.fkit.domain.StudentBean; import java.util.List; import org.apache.ibatis.annotations.Many; /** * @author Administrator * */ public interface CoursesMapper { /** * 根据id查询课程 * @param id * @return */ @Select("select * from t_courses where id=#{id}") @Results({ @Result(id=true,column="id",property="id"), @Result(column="courses_name",property="name"), }) public CoursesBean findCouById(int id); /** * 根据学生id查询学生的所有课程 * @param id * @return */ @Select("select * from t_courses where id in (select cou_id from t_stu_cou where stu_id = #{id})") @Results({ @Result(id=true,column="id",property="id"), @Result(column="courses_name",property="name"), }) public List<CoursesBean> findCoursesByStudent(int id); /** * 要求查课时,将选课的学生一并查出 * @param id * @return */ @Select("select * from t_courses where id=#{id}") @Results({ @Result(id=true,column="id",property="id"), @Result(column="courses_name",property="name"), @Result(column="id",property="student", many=@Many(select="org.fkit.mapper.StudentMapper.findStudentByCourses",fetchType=FetchType.LAZY)) }) public CoursesBean findCouAndStu(int id); }
StudentMapper.java
package org.fkit.mapper; import java.util.List; import org.apache.ibatis.annotations.Many; import org.apache.ibatis.annotations.Result; import org.apache.ibatis.annotations.Results; import org.apache.ibatis.annotations.Select; import org.apache.ibatis.mapping.FetchType; import org.fkit.domain.CoursesBean; import org.fkit.domain.StudentBean; public interface StudentMapper { /** * 根据id值查询学生信息 * @param id * @return */ @Select("select * from t_student where id = #{id}") @Results({ @Result(id=true,column="id",property="id"), @Result(column="student_name",property="name") }) public StudentBean findStuById(int id); /** * 根据课程id查询课程的所有学生 * @param id * @return */ @Select(" select * from t_student where id in (select stu_id from t_stu_cou where cou_id=#{id})") @Results({ @Result(id=true,column="id",property="id"), @Result(column="student_name",property="name") }) public List<StudentBean> findStudentByCourses(int id); /** * 要求查询学生时,将学生选择的课程查出 * @param id * @return */ @Select("select * from t_student where id=#{id}") @Results({ @Result(id=true,column="id",property="id"), @Result(column="student_name",property="name"), @Result(column="id",property="courses", many=@Many(select="org.fkit.mapper.CoursesMapper.findCoursesByStudent",fetchType=FetchType.LAZY)) }) public StudentBean findStuAndCou(int id); }
4.mybatis-config.xml
db.properties
driver=com.mysql.jdbc.Driver url=jdbc:mysql://127.0.0.1:3306/mybatis username=root password=123456
log4j.properties
# Global logging configuration log4j.rootLogger=ERROR, stdout # MyBatis logging configuration... log4j.logger.org.fkit.mapper.PersonMapper=DEBUG log4j.logger.org.fkit.mapper.CardMapper=DEBUG # Console output... log4j.appender.stdout=org.apache.log4j.ConsoleAppender log4j.appender.stdout.layout=org.apache.log4j.PatternLayout log4j.appender.stdout.layout.ConversionPattern=%5p [%t] - %m%n
mybatis-config.xml
<?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"> <!-- XML 配置文件包含对 MyBatis 系统的核心设置 --> <configuration> <properties resource="db.properties" /> <!-- 指定 MyBatis 所用日志的具体实现 --> <settings> <setting name="logImpl" value="LOG4J" /> </settings> <!-- 为JAVA Bean起类别名 --> <typeAliases> <package name="org.fkit.domain" /> </typeAliases> <environments default="mysql"> <!-- 环境配置,即连接的数据库。 --> <environment id="mysql"> <!-- 指定事务管理类型,type="JDBC"指直接简单使用了JDBC的提交和回滚设置 --> <transactionManager type="JDBC" /> <!-- dataSource指数据源配置,POOLED是JDBC连接对象的数据源连接池的实现。 --> <dataSource type="POOLED"> <property name="driver" value="${driver}" /> <property name="url" value="${url}" /> <property name="username" value="${username}" /> <property name="password" value="${password}" /> </dataSource> </environment> </environments> <!-- mappers告诉了MyBatis去哪里找持久化类的映射文件 --> <mappers> <mapper class="org.fkit.mapper.CoursesMapper" /> <mapper class="org.fkit.mapper.StudentMapper" /> </mappers> </configuration>
5.测试
ManyToManyTest.java
package org.fkit.test; import java.io.IOException; import java.io.InputStream; import java.util.List; 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.fkit.domain.CoursesBean; import org.fkit.domain.StudentBean; import org.fkit.mapper.CoursesMapper; import org.fkit.mapper.StudentMapper; public class ManyToManyTest { public static void main(String[] args) throws IOException { // 读取mybatis-config.xml文件 InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml"); // 初始化mybatis,创建SqlSessionFactory类的实例 SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder() .build(inputStream); // 创建Session实例 SqlSession session = sqlSessionFactory.openSession(); ManyToManyTest t = new ManyToManyTest(); // 根据用户id查询用户,测试一对多 //t.testSelectCoursesById(session); // 根据订单id查询订单,测试多对多 t.testSelectStudentById(session); // 提交事务 session.commit(); // 关闭Session session.close(); } public void testSelectStudentById(SqlSession session){ // 获得UserMapper接口的代理对象 StudentMapper sm = session.getMapper(StudentMapper.class); // 调用selectUserById方法 StudentBean stu = sm.findStuAndCou(2); System.out.println(stu); // 查看查询到的user对象信息 System.out.println(stu.getId() + " " + stu.getName()); // 查看user对象关联的订单信息 List<CoursesBean> CoursesList = stu.getCourses(); for(CoursesBean item : CoursesList){ System.out.println(item); } } // 测试多对多,查询订单Order(多)的时候级联查询订单的商品Article(多) public void testSelectCoursesById(SqlSession session){ // 获得OrderMapper接口的代理对象 CoursesMapper cm = session.getMapper(CoursesMapper.class); // 调用selectOrderById方法 CoursesBean course = cm.findCouAndStu(2); System.out.println(course); // 查看查询到的order对象信息 System.out.println(course.getId() + " " + course.getName()); // 查看order对象关联的商品信息 List<StudentBean> studentlist = course.getStudent(); for(StudentBean stu : studentlist){ System.out.println(stu); } } }
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