Mybatis的注解开发
Posted xuweiweiwoaini
tags:
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前言
- 注解开发虽然不如XML开发那样,可以完全做到代码和配置文件分离,但是其开发灵活快速的特性,使得在企业开发中的地位日益显著,而Mybatis作为时下最流行的持久层框架,掌握Mybatis注解开发势在必行。
环境准备
- sql脚本:
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`username` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL COMMENT ‘用户名‘,
`birthday` datetime(0) NULL DEFAULT NULL COMMENT ‘生日‘,
`gender` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL COMMENT ‘性别‘,
`address` varchar(255) CHARACTER SET utf8mb4 COLLATE utf8mb4_general_ci NULL DEFAULT NULL COMMENT ‘地址‘,
PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB AUTO_INCREMENT = 1 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = Dynamic;
DROP TABLE IF EXISTS `account`;
CREATE TABLE `account` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`user_id` int(11) NULL DEFAULT NULL COMMENT ‘外键‘,
`money` double NULL DEFAULT NULL COMMENT ‘存款‘,
PRIMARY KEY (`id`) USING BTREE,
INDEX `fk_user_id`(`user_id`) USING BTREE,
CONSTRAINT `fk_user_id` FOREIGN KEY (`user_id`) REFERENCES `user` (`id`) ON DELETE RESTRICT ON UPDATE RESTRICT
) ENGINE = InnoDB AUTO_INCREMENT = 1 CHARACTER SET = utf8mb4 COLLATE = utf8mb4_general_ci ROW_FORMAT = Dynamic;
- 导入相关jar包的Maven坐标:
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.4.1</version>
</dependency>
<dependency>
<groupId>log4j</groupId>
<artifactId>log4j</artifactId>
<version>1.2.17</version>
</dependency>
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>8.0.21</version>
</dependency>
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.13</version>
<scope>test</scope>
</dependency>
- 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">
<configuration>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="com.mysql.cj.jdbc.Driver"/>
<property name="url"
value="jdbc:mysql://192.168.134.100:3306/test?useUnicode=true&characterEncoding=UTF-8&autoReconnect=true&useSSL=false&serverTimezone=GMT%2B8&allowPublicKeyRetrieval=true"/>
<property name="username" value="root"/>
<property name="password" value="123456"/>
</dataSource>
</environment>
</environments>
<mappers>
<package name="com.sunxiaping.mapper"/>
</mappers>
</configuration>
- log4j.xml
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">
<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">
<appender name="STDOUT" class="org.apache.log4j.ConsoleAppender">
<param name="Encoding" value="UTF-8" />
<layout class="org.apache.log4j.PatternLayout">
<param name="ConversionPattern" value="%-5p %d{MM-dd HH:mm:ss,SSS} %m (%F:%L)
" />
</layout>
</appender>
<logger name="java.sql">
<level value="debug" />
</logger>
<logger name="org.apache.ibatis">
<level value="info" />
</logger>
<root>
<level value="debug" />
<appender-ref ref="STDOUT" />
</root>
</log4j:configuration>
Mybatis注解实现常用的CRUD
- User.java
package com.sunxiaping.domain;
import java.io.Serializable;
import java.util.Date;
public class User implements Serializable {
private Integer id;
private String username;
private Date birthday;
private String gender;
private String address;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", username=‘" + username + ‘‘‘ +
", birthday=" + birthday +
", gender=‘" + gender + ‘‘‘ +
", address=‘" + address + ‘‘‘ +
‘}‘;
}
}
- UserMapper.java
package com.sunxiaping.mapper;
import com.sunxiaping.domain.User;
import org.apache.ibatis.annotations.*;
import java.util.List;
public interface UserMapper {
/**
* 查询所有用户信息
*
* @return
*/
@Select(" SELECT * FROM `user`")
@Results({
@Result(id = true, property = "id", column = "id"),
@Result(property = "username", column = "username"),
@Result(property = "birthday", column = "birthday"),
@Result(property = "gender", column = "gender"),
@Result(property = "address", column = "address"),
})
List<User> findAll();
/**
* 添加用户信息
*
* @param user
*/
@Insert(" INSERT INTO `user` (username,birthday,gender,address) VALUES (#{username},#{birthday},#{gender},#{address})")
void saveUser(User user);
/**
* 修改用户信息
*
* @param user
*/
@Update(" UPDATE `user` set username = #{username},gender= #{gender} ,address = #{address} WHERE id = #{id} ")
void updateUser(User user);
/**
* 删除用户信息
*
* @param id
*/
@Delete(" DELETE FROM `user` WHERE id = #{id} ")
void deleteById(Integer id);
}
- 测试:
package com.sunxiaping;
import com.sunxiaping.domain.User;
import com.sunxiaping.mapper.UserMapper;
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.After;
import org.junit.Before;
import org.junit.Test;
import java.io.IOException;
import java.io.InputStream;
import java.util.Date;
import java.util.List;
public class UserTest {
SqlSessionFactory sqlSessionFactory = null;
SqlSession sqlSession = null;
@Before
public void before() throws IOException {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
}
@After
public void after() {
if (sqlSession != null) {
sqlSession.close();
}
}
@Test
public void testFindAll() throws IOException {
sqlSession = sqlSessionFactory.openSession(true);
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
List<User> userList = userMapper.findAll();
System.out.println("userList = " + userList);
}
@Test
public void testSaveUser() {
sqlSession = sqlSessionFactory.openSession(true);
User user = new User();
user.setUsername("zhangsan");
user.setBirthday(new Date());
user.setGender("男");
user.setAddress("江苏苏州");
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
userMapper.saveUser(user);
}
@Test
public void testUpdateUser() {
sqlSession = sqlSessionFactory.openSession(true);
User user = new User();
user.setId(1);
user.setUsername("张三");
user.setGender("女");
user.setAddress("江苏苏州");
user.setBirthday(new Date());
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
userMapper.updateUser(user);
}
@Test
public void testDeleteById() {
sqlSession = sqlSessionFactory.openSession(true);
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
userMapper.deleteById(1);
}
}
Mybatis注解实现一对一关联查询
- 示例:
- User.java
package com.sunxiaping.domain;
import java.io.Serializable;
import java.util.Date;
public class User implements Serializable {
private Integer id;
private String username;
private Date birthday;
private String gender;
private String address;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", username=‘" + username + ‘‘‘ +
", birthday=" + birthday +
", gender=‘" + gender + ‘‘‘ +
", address=‘" + address + ‘‘‘ +
‘}‘;
}
}
- UserMapper.java
package com.sunxiaping.mapper;
import com.sunxiaping.domain.User;
import org.apache.ibatis.annotations.Select;
public interface UserMapper {
/**
* 根据id查询用户信息
*
* @param id
* @return
*/
@Select("SELECT * FROM `user` WHERE id = #{id}")
User findById(Integer id);
}
- Account.java
package com.sunxiaping.domain;
import java.io.Serializable;
public class Account implements Serializable {
private Integer id;
private Double money;
/**
* 一个账户属于一个用户
*/
private User user;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public Double getMoney() {
return money;
}
public void setMoney(Double money) {
this.money = money;
}
public User getUser() {
return user;
}
public void setUser(User user) {
this.user = user;
}
@Override
public String toString() {
return "Account{" +
"id=" + id +
", money=" + money +
", user=" + user +
‘}‘;
}
}
- AccountMapper.java
package com.sunxiaping.mapper;
import com.sunxiaping.domain.Account;
import com.sunxiaping.domain.User;
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 java.util.List;
public interface AccountMapper {
/**
* 查询所有账户以及所属用户信息
*
* @return
*/
@Select(" SELECT * FROM `account`")
@Results(value = {
@Result(id = true, property = "id", column = "id"),
@Result(property = "money", column = "money"),
@Result(property = "user", column = "user_id", javaType = User.class, one = @One(select = "com.sunxiaping.mapper.UserMapper.findById",fetchType = FetchType.LAZY))
})
List<Account> findAccountWithUser();
}
- 测试:
package com.sunxiaping;
import com.sunxiaping.domain.Account;
import com.sunxiaping.mapper.AccountMapper;
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.After;
import org.junit.Before;
import org.junit.Test;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
public class AccountTest {
SqlSessionFactory sqlSessionFactory = null;
SqlSession sqlSession = null;
@Before
public void before() throws IOException {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
}
@After
public void after() {
if (sqlSession != null) {
sqlSession.close();
}
}
@Test
public void test(){
sqlSession = sqlSessionFactory.openSession(true);
AccountMapper accountMapper = sqlSession.getMapper(AccountMapper.class);
List<Account> accountList = accountMapper.findAccountWithUser();
System.out.println("accountList = " + accountList);
}
}
Mybatis注解实现一对多关联查询
- 示例:
- User.java
package com.sunxiaping.domain;
import java.io.Serializable;
import java.util.Date;
import java.util.List;
public class User implements Serializable {
private Integer id;
private String username;
private Date birthday;
private String gender;
private String address;
private List<Account> accountList;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public Date getBirthday() {
return birthday;
}
public void setBirthday(Date birthday) {
this.birthday = birthday;
}
public String getGender() {
return gender;
}
public void setGender(String gender) {
this.gender = gender;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public List<Account> getAccountList() {
return accountList;
}
public void setAccountList(List<Account> accountList) {
this.accountList = accountList;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", username=‘" + username + ‘‘‘ +
", birthday=" + birthday +
", gender=‘" + gender + ‘‘‘ +
", address=‘" + address + ‘‘‘ +
", accountList=" + accountList +
‘}‘;
}
}
- Account.java
package com.sunxiaping.domain;
import java.io.Serializable;
public class Account implements Serializable {
private Integer id;
private Double money;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public Double getMoney() {
return money;
}
public void setMoney(Double money) {
this.money = money;
}
@Override
public String toString() {
return "Account{" +
"id=" + id +
", money=" + money +
‘}‘;
}
}
- AccountMapper.java
package com.sunxiaping.mapper;
import com.sunxiaping.domain.Account;
import org.apache.ibatis.annotations.Result;
import org.apache.ibatis.annotations.Results;
import org.apache.ibatis.annotations.Select;
public interface AccountMapper {
@Select("SELECT * FROM `account`")
@Results({
@Result(id = true, property = "id", column = "id"),
@Result(property = "money", column = "money")}
)
Account findById(Integer id);
}
- UserMapper.java
package com.sunxiaping.mapper;
import com.sunxiaping.domain.User;
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 java.util.List;
public interface UserMapper {
@Select(" SELECT * FROM `user`")
@Results({
@Result(id = true, property = "id", column = "id"),
@Result(property = "username", column = "username"),
@Result(property = "birthday", column = "birthday"),
@Result(property = "gender", column = "gender"),
@Result(property = "address", column = "address"),
@Result(property = "accountList", column = "id", many = @Many(select = "com.sunxiaping.mapper.AccountMapper.findById")),
})
List<User> findAll();
}
- 测试:
package com.sunxiaping;
import com.sunxiaping.domain.User;
import com.sunxiaping.mapper.UserMapper;
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.After;
import org.junit.Before;
import org.junit.Test;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
public class UserTest {
SqlSessionFactory sqlSessionFactory = null;
SqlSession sqlSession = null;
@Before
public void before() throws IOException {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
}
@After
public void after() {
if (sqlSession != null) {
sqlSession.close();
}
}
@Test
public void test() {
sqlSession = sqlSessionFactory.openSession(true);
UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
List<User> userList = userMapper.findAll();
System.out.println("userList = " + userList);
}
}
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