MyBatis注解开发多表代码操作——手把手教你实战操作
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文章目录
0. MyBatis的注解实现复杂映射开发
实现复杂关系映射之前我们可以在映射文件中通过配置来实现，使用注解开发后，我们可以使用@Results注解，@Result注解，@One注解，@Many注解组合完成复杂关系的配置
1. 项目准备工作
目录结构
1.1 建表
-- ----------------------------
-- Table structure for card
-- ----------------------------
DROP TABLE IF EXISTS `card`;
CREATE TABLE `card` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`number` varchar(30) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NULL DEFAULT NULL,
`pid` int(11) NULL DEFAULT NULL,
PRIMARY KEY (`id`) USING BTREE,
INDEX `cp_fk`(`pid`) USING BTREE
) ENGINE = MyISAM AUTO_INCREMENT = 4 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_unicode_ci ROW_FORMAT = Dynamic;
-- ----------------------------
-- Records of card
-- ----------------------------
INSERT INTO `card` VALUES (1, '12345', 1);
INSERT INTO `card` VALUES (2, '23456', 2);
INSERT INTO `card` VALUES (3, '34567', 3);
-- ----------------------------
-- Table structure for classes
-- ----------------------------
DROP TABLE IF EXISTS `classes`;
CREATE TABLE `classes` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`NAME` varchar(20) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NULL DEFAULT NULL,
PRIMARY KEY (`id`) USING BTREE
) ENGINE = MyISAM AUTO_INCREMENT = 3 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_unicode_ci ROW_FORMAT = Dynamic;
-- ----------------------------
-- Records of classes
-- ----------------------------
INSERT INTO `classes` VALUES (1, '极地一班');
INSERT INTO `classes` VALUES (2, '极地二班');
-- ----------------------------
-- Table structure for course
-- ----------------------------
DROP TABLE IF EXISTS `course`;
CREATE TABLE `course` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`NAME` varchar(20) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NULL DEFAULT NULL,
PRIMARY KEY (`id`) USING BTREE
) ENGINE = MyISAM AUTO_INCREMENT = 3 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_unicode_ci ROW_FORMAT = Dynamic;
-- ----------------------------
-- Records of course
-- ----------------------------
INSERT INTO `course` VALUES (1, '语文');
INSERT INTO `course` VALUES (2, '数学');
-- ----------------------------
-- Table structure for person
-- ----------------------------
DROP TABLE IF EXISTS `person`;
CREATE TABLE `person` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`NAME` varchar(20) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NULL DEFAULT NULL,
`age` int(11) NULL DEFAULT NULL,
PRIMARY KEY (`id`) USING BTREE
) ENGINE = MyISAM AUTO_INCREMENT = 4 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_unicode_ci ROW_FORMAT = Dynamic;
-- ----------------------------
-- Records of person
-- ----------------------------
INSERT INTO `person` VALUES (1, '张三', 23);
INSERT INTO `person` VALUES (2, '李四', 24);
INSERT INTO `person` VALUES (3, '王五', 25);
-- ----------------------------
-- Table structure for stu_cr
-- ----------------------------
DROP TABLE IF EXISTS `stu_cr`;
CREATE TABLE `stu_cr` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`sid` int(11) NULL DEFAULT NULL,
`cid` int(11) NULL DEFAULT NULL,
PRIMARY KEY (`id`) USING BTREE,
INDEX `sc_fk1`(`sid`) USING BTREE,
INDEX `sc_fk2`(`cid`) USING BTREE
) ENGINE = MyISAM AUTO_INCREMENT = 5 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_unicode_ci ROW_FORMAT = Fixed;
-- ----------------------------
-- Records of stu_cr
-- ----------------------------
INSERT INTO `stu_cr` VALUES (1, 1, 1);
INSERT INTO `stu_cr` VALUES (2, 1, 2);
INSERT INTO `stu_cr` VALUES (3, 2, 1);
INSERT INTO `stu_cr` VALUES (4, 2, 2);
-- ----------------------------
-- Table structure for student
-- ----------------------------
DROP TABLE IF EXISTS `student`;
CREATE TABLE `student` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`NAME` varchar(30) CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci NULL DEFAULT NULL,
`age` int(11) NULL DEFAULT NULL,
`cid` int(11) NULL DEFAULT NULL,
PRIMARY KEY (`id`) USING BTREE,
INDEX `cs_fk`(`cid`) USING BTREE
) ENGINE = MyISAM AUTO_INCREMENT = 5 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_unicode_ci ROW_FORMAT = Dynamic;
-- ----------------------------
-- Records of student
-- ----------------------------
INSERT INTO `student` VALUES (1, '张三', 23, 1);
INSERT INTO `student` VALUES (2, '李四', 24, 1);
INSERT INTO `student` VALUES (3, '王五', 25, 2);
INSERT INTO `student` VALUES (4, '赵六', 26, 2);
SET FOREIGN_KEY_CHECKS = 1;
1.2 MybatisConfig.xml配置
<?xml version="1.0" encoding="UTF-8" ?>
<!--MyBatis的DTD约束-->
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<!--configuration 核心根标签-->
<configuration>
<!--引入数据库连接的配置文件-->
<properties resource="jdbc.properties"/>
<!--配置LOG4J-->
<settings>
<setting name="logImpl" value="log4j"/>
</settings>
<!--起别名-->
<typeAliases>
<package name="com.yyl.bean"/>
</typeAliases>
<!--environments配置数据库环境，环境可以有多个。default属性指定使用的是哪个-->
<environments default="mysql">
<!--environment配置数据库环境 id属性唯一标识-->
<environment id="mysql">
<!-- transactionManager事务管理。 type属性，采用JDBC默认的事务-->
<transactionManager type="JDBC"></transactionManager>
<!-- dataSource数据源信息 type属性 连接池-->
<dataSource type="POOLED">
<!-- property获取数据库连接的配置信息 -->
<property name="driver" value="$driver" />
<property name="url" value="$url" />
<property name="username" value="$username" />
<property name="password" value="$password" />
</dataSource>
</environment>
</environments>
<!--配置映射关系-->
<mappers>
<package name="com.yyl"/>
</mappers>
</configuration>
1.3 properties
jdbc
driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/db2
username=root
password=root
log4j
# Global logging configuration
# ERROR WARN INFO DEBUG
log4j.rootLogger=DEBUG, stdout
# 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
1.4 Bean
Card
package com.yyl.bean;
public class Card
private Integer id; //主键id
private String number; //身份证号
private Person p; //所属人的对象
public Card()
public Card(Integer id, String number, Person p)
this.id = id;
this.number = number;
this.p = p;
public Integer getId()
return id;
public void setId(Integer id)
this.id = id;
public String getNumber()
return number;
public void setNumber(String number)
this.number = number;
public Person getP()
return p;
public void setP(Person p)
this.p = p;
@Override
public String toString()
return "Card" +
"id=" + id +
", number='" + number + '\\'' +
", p=" + p +
'';
Classes
package com.yyl.bean;
import java.util.List;
public class Classes
private Integer id; //主键id
private String name; //班级名称
private List<Student> students; //班级中所有学生对象
public Classes()
public Classes(Integer id, String name, List<Student> students)
this.id = id;
this.name = name;
this.students = students;
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<Student> getStudents()
return students;
public void setStudents(List<Student> students)
this.students = students;
@Override
public String toString()
return "Classes" +
"id=" + id +
", name='" + name + '\\'' +
", students=" + students +
'';
Course
package com.yyl.bean;
public class Course
private Integer id; //主键id
private String name; //课程名称
public Course()
public Course(Integer id, String name)
this.id = id;
this.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;
@Override
public String toString()
return "Course" +
"id=" + id +
", name='" + name + MyBatis多表操作