ORM框架之Mybatis（六）mybatis通用mapper

其他 2020-02-19 18:17:16 阅读次数: 0

一、简介通用mapper

1.1 官方介绍：（官网：https://mapperhelper.github.io/docs/）

通用Mapper都可以极大的方便开发人员。可以随意的按照自己的需要选择通用方法，还可以很方便的开发自己的通用方法。

极其方便的使用MyBatis单表的增删改查。

支持单表操作，不支持通用的多表联合查询。

  • 不是表中字段的属性必须加 @Transient 注解
  • 通用 Mapper 不支持 devtools 热加载

1.2 代码官方托管地址：（也是刘增辉开源项目，他还开源了一个很牛的分页插件page—helper）

github地址：https://github.com/abel533/Mapper

码云地址：https://gitee.com/free/Mapper

二、通用mapper实例演示

2.1 创建项目用数据表：

首先创建数据库common_mapper（使用的是mysql数据库）

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然后在该数据库下创建数据表：

CREATE TABLE `tabple_emp` (
`emp_id` int NOT NULL AUTO_INCREMENT ,
`emp_name` varchar(500) NULL ,
`emp_salary` double(15,5) NULL ,
`emp_age` int NULL ,
PRIMARY KEY (`emp_id`)
);
INSERT INTO `tabple_emp` (`emp_name`, `emp_salary`, `emp_age`) VALUES ('tom', '1254.37', '27');
INSERT INTO `tabple_emp` (`emp_name`, `emp_salary`, `emp_age`) VALUES ('jerry', '6635.42', '38');
INSERT INTO `tabple_emp` (`emp_name`, `emp_salary`, `emp_age`) VALUES ('bob', '5560.11', '40');
INSERT INTO `tabple_emp` (`emp_name`, `emp_salary`, `emp_age`) VALUES ('kate', '2209.11', '22');
INSERT INTO `tabple_emp` (`emp_name`, `emp_salary`, `emp_age`) VALUES ('justin', '4203.15', '30');

创建好之后：

2.2 创建maven项目Pro01Mapper

2.2.1配置pom文件：

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
	<modelVersion>4.0.0</modelVersion>
	<groupId>com.xiaomifeng1010.mapper</groupId>
	<artifactId>Pro01Mapper</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<dependencies>
		<dependency>
			<groupId>tk.mybatis</groupId>
			<artifactId>mapper</artifactId>
			<version>4.0.0-beta3</version>
		</dependency>
		<dependency>
			<groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>4.9</version>
		</dependency>
		<dependency>
			<groupId>log4j</groupId>
			<artifactId>log4j</artifactId>
			<version>1.2.17</version>
		</dependency>
		<dependency>
			<groupId>cglib</groupId>
			<artifactId>cglib</artifactId>
			<version>2.2</version>
		</dependency>
		<dependency>
			<groupId>org.aspectj</groupId>
			<artifactId>aspectjweaver</artifactId>
			<version>1.6.8</version>
		</dependency>
		<dependency>
			<groupId>org.slf4j</groupId>
			<artifactId>slf4j-api</artifactId>
			<version>1.7.7</version>
		</dependency>
		<dependency>
			<groupId>org.slf4j</groupId>
			<artifactId>slf4j-log4j12</artifactId>
			<version>1.7.7</version>
		</dependency>
		<dependency>
			<groupId>org.mybatis</groupId>
			<artifactId>mybatis</artifactId>
			<version>3.2.8</version>
		</dependency>
		<dependency>
			<groupId>org.mybatis</groupId>
			<artifactId>mybatis-spring</artifactId>
			<version>1.2.2</version>
		</dependency>
		<dependency>
			<groupId>com.mchange</groupId>
			<artifactId>c3p0</artifactId>
			<version>0.9.2</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-context</artifactId>
			<version>4.3.10.RELEASE</version>
		</dependency>
		<dependency>
			<groupId>mysql</groupId>
			<artifactId>mysql-connector-java</artifactId>
			<version>5.1.37</version>
		</dependency>
		<dependency>
			<groupId>org.springframework</groupId>
			<artifactId>spring-orm</artifactId>
			<version>4.3.10.RELEASE</version>
		</dependency>
	</dependencies>
</project>

注意mapper需要的依赖为：

<dependency>
<groupId>tk.mybatis</groupId>
<artifactId>mapper</artifactId>
<version>4.0.0-beta3</version>
</dependency>

2.2.2 在resources文件夹下配置spring-context.xml、mybatis-config.xml、log4j.properties、jdbc.properties

spring-context.xml配置文件：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:aop="http://www.springframework.org/schema/aop"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:tx="http://www.springframework.org/schema/tx"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.3.xsd
		http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.3.xsd
		http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.3.xsd">
	
	<!-- 配置数据源 -->
	<context:property-placeholder location="classpath:jdbc.properties"/>

	<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource">
		<property name="user" value="${jdbc.user}"/>
		<property name="password" value="${jdbc.password}"/>
		<property name="jdbcUrl" value="${jdbc.url}"/>
		<property name="driverClass" value="${jdbc.driver}"/>
	</bean>

	<!-- 整合MyBatis -->
	<bean id="sqlSessionFactoryBean" class="org.mybatis.spring.SqlSessionFactoryBean">
		<property name="configLocation" value="classpath:mybatis-config.xml"/>
		<property name="dataSource" ref="dataSource"/>
	</bean>
	
	<!-- 整合通用Mapper所需要做的配置修改： -->
	<!-- 原始全类名：org.mybatis.spring.mapper.MapperScannerConfigurer -->
	<!-- 通用Mapper使用：tk.mybatis.spring.mapper.MapperScannerConfigurer -->
	<bean class="tk.mybatis.spring.mapper.MapperScannerConfigurer">
		<property name="basePackage" value="com.xiaomifeng1010.mapper.mappers"/>
	</bean>

	<!-- 配置Service自动扫描的包 -->
	<context:component-scan base-package="com.xiaomifeng1010.mapper.services"/>

	<!-- 配置声明式事务 -->
	<bean id="dataSourceTransactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
		<property name="dataSource" ref="dataSource"/>
	</bean>

	<aop:config>
		<aop:advisor advice-ref="txAdvice" pointcut="execution(* *..*Service.*(..))"/>
	</aop:config>

	<tx:advice id="txAdvice" transaction-manager="dataSourceTransactionManager">
		<tx:attributes>
			<tx:method name="get*" read-only="true"/>
			<tx:method name="save*" rollback-for="java.lang.Exception" propagation="REQUIRES_NEW"/>
			<tx:method name="remove*" rollback-for="java.lang.Exception" propagation="REQUIRES_NEW"/>
			<tx:method name="update*" rollback-for="java.lang.Exception" propagation="REQUIRES_NEW"/>
		</tx:attributes>
	</tx:advice>
</beans>

mybatis-config.xml配置文件：

<?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>

</configuration>

log4j.properties配置文件：

log4j.rootLogger=DEBUG,myConsole
log4j.appender.myConsole=org.apache.log4j.ConsoleAppender
log4j.appender.myConsole.ImmediateFlush=true
log4j.appender.myConsole.Target=System.out
log4j.appender.myConsole.layout=org.apache.log4j.PatternLayout
log4j.appender.myConsole.layout.ConversionPattern=[%-5p] %d(%r) --> [%t] %l: %m %x %n

log4j.logger.com.mchange.v2=ERROR

jdbc.properties配置文件

jdbc.user=root
jdbc.password=123456
jdbc.url=jdbc:mysql://localhost:3306/common_mapper?useUnicode=true&characterEncoding=utf8
jdbc.driver=com.mysql.jdbc.Driver

2.3创建实体类和mapper类

package com.xiaomifeng1010.mapper.entities;

import javax.persistence.Column;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name="tabple_emp")
public class Employee {
	
	@Id
	@GeneratedValue(strategy=GenerationType.IDENTITY)
	private Integer empId;//emp_id
	@Column(name="emp_name")
	private String empName;//emp_name
	
	@Column(name="emp_salary")
	private Double empSalary;//emp_salary
	@Column(name="emp_age")
	private Integer empAge;//emp_age
	
	public Employee() {
		
	}

	public Employee(Integer empId, String empName, Double empSalary, Integer empAge) {
		super();
		this.empId = empId;
		this.empName = empName;
		this.empSalary = empSalary;
		this.empAge = empAge;
	}

	@Override
	public String toString() {
		return "Employee [empId=" + empId + ", empName=" + empName + ", empSalary=" + empSalary + ", empAge=" + empAge
				+ "]";
	}

	public Integer getEmpId() {
		return empId;
	}

	public void setEmpId(Integer empId) {
		this.empId = empId;
	}

	public String getEmpName() {
		return empName;
	}

	public void setEmpName(String empName) {
		this.empName = empName;
	}

	public Double getEmpSalary() {
		return empSalary;
	}

	public void setEmpSalary(Double empSalary) {
		this.empSalary = empSalary;
	}

	public Integer getEmpAge() {
		return empAge;
	}

	public void setEmpAge(Integer empAge) {
		this.empAge = empAge;
	}

}

创建mapper类：

package com.xiaomifeng1010.mapper.mappers;

import com.xiaomifeng1010.mapper.entities.Employee;

import tk.mybatis.mapper.common.Mapper;

/**
 * 具体操作数据库的Mapper接口，需要继承通用Mapper提供的核心接口：Mapper<Employee>
 * 泛型类型就是实体类的类型
 * @author Lenovo
 *
 */
public interface EmployeeMapper extends Mapper<Employee> {
	
}

继承通用mapper接口即可，查看mapper接口源码：

通过继承mapper接口，既可以生成基本的增删改查方法。

创建service类

package com.xiaomifeng1010.mapper.services;

import java.util.List;

import org.apache.ibatis.session.RowBounds;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import com.xiaomifeng1010.mapper.entities.Employee;
import com.xiaomifeng1010.mapper.mappers.EmployeeMapper;

import tk.mybatis.mapper.entity.Example;

@Service
public class EmployeeService {
	
	@Autowired
	private EmployeeMapper employeeMapper;

	public Employee getOne(Employee employeeQueryCondition) {
		
		return employeeMapper.selectOne(employeeQueryCondition);
	}

	public Employee getEmployeeById(Integer empId) {
		return employeeMapper.selectByPrimaryKey(empId);
	}

	public boolean isExists(Integer empId) {
		return employeeMapper.existsWithPrimaryKey(empId);
	}

	public void saveEmployee(Employee employee) {
		employeeMapper.insert(employee);
	}

	public void saveEmployeeSelective(Employee employee) {
		employeeMapper.insertSelective(employee);
	}

	public void updateEmployeeSelective(Employee employee) {
		employeeMapper.updateByPrimaryKeySelective(employee);
	}

	public void removeEmployee(Employee employee) {
		employeeMapper.delete(employee);
	}

	public void removeEmployeeById(Integer empId) {
		employeeMapper.deleteByPrimaryKey(empId);
	}

	public List<Employee> getEmpListByExample(Example example) {
		return employeeMapper.selectByExample(example);
	}

	public List<Employee> getEmpListByRowBounds(RowBounds rowBounds) {
		return employeeMapper.selectByRowBounds(null, rowBounds);
	}

}

2.4 单元测试类，编写测试方法

package com.xiaomifeng1010.mapper.test;

import java.sql.Connection;
import java.sql.SQLException;

import javax.sql.DataSource;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class MapperTest {
	
	private ApplicationContext iocContainer = new ClassPathXmlApplicationContext("spring-context.xml");
	
	@Test
	public void testDataSource() throws SQLException {
		DataSource dataSource = iocContainer.getBean(DataSource.class);
		Connection connection = dataSource.getConnection();
		System.out.println(connection);
	}
	
}

运行后：

获取到了连接。

测试具体增删改查方法：

package com.xiaomifeng1010.mapper.test;

import java.util.List;

import org.apache.ibatis.session.RowBounds;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import com.xiaomifeng1010.mapper.entities.Employee;
import com.xiaomifeng1010.mapper.services.EmployeeService;

import tk.mybatis.mapper.entity.Example;
import tk.mybatis.mapper.entity.Example.Criteria;

public class EmployeeMapperTest {
	
	private ApplicationContext iocContainer = new ClassPathXmlApplicationContext("spring-context.xml");
	private EmployeeService employeeService = iocContainer.getBean(EmployeeService.class);

	@Test
	public void testSelectOne() {
		
		//1.创建封装查询条件的实体类对象
		Employee employeeQueryCondition = new Employee(null, "bob", 5560.11, null);
		
		//2.执行查询
		Employee employeeQueryResult = employeeService.getOne(employeeQueryCondition);
		
		//3.打印
		System.out.println(employeeQueryResult);
	}

	@Test
	public void testSelect() {
		
	}

	@Test
	public void testSelectAll() {
		
	}

	@Test
	public void testSelectCount() {
		
	}

	@Test
	public void testSelectByPrimaryKey() {
		
		//1.提供id值
		Integer empId = 3;
		
		//2.执行根据主键进行的查询
		Employee employee = employeeService.getEmployeeById(empId);
		
		//3.打印结果
		System.out.println(employee);
		
	}

	@Test
	public void testExistsWithPrimaryKey() {
		
		//1.提供主键值
		Integer empId = 33;
		
		//2.执行查询
		boolean exists = employeeService.isExists(empId);
		
		//3.打印结果
		System.out.println(exists);
		
	}

	@Test
	public void testInsert() {
		
		//1.创建实体类对象封装要保存到数据库的数据
		Employee employee = new Employee(null, "emp03", 3000.00, 23);
		
		//2.执行插入操作
		employeeService.saveEmployee(employee);
		
		//3.获取employee对象的主键字段值
		Integer empId = employee.getEmpId();
		System.out.println("empId="+empId);
		
	}

	@Test
	public void testInsertSelective() {
		
		//1.创建实体类对象封装要保存到数据库的数据
		Employee employee = new Employee(null, "emp04", null, 23);
		
		//2.执行插入操作
		employeeService.saveEmployeeSelective(employee);
		
	}

	@Test
	public void testUpdateByPrimaryKey() {
		
	}

	@Test
	public void testUpdateByPrimaryKeySelective() {
		
		//1.创建用于测试的实体类
		Employee employee = new Employee(7, "empNewName", null, null);
		
		//2.执行更新
		employeeService.updateEmployeeSelective(employee);
		
	}

	@Test
	public void testDelete() {
		
		//1.声明实体类变量作为查询条件
		Employee employee = null;
		
		//2.执行删除
		employeeService.removeEmployee(employee);
		
	}

	@Test
	public void testDeleteByPrimaryKey() {
		
		//1.提供主键值
		Integer empId = 13;
		
		//2.执行删除
		employeeService.removeEmployeeById(empId);
		
	}

	@Test
	public void testSelectByExample() {
		
		//目标：WHERE (emp_salary>? AND emp_age<?) OR (emp_salary<? AND emp_age>?)
		//1.创建Example对象
		Example example = new Example(Employee.class);
		
		//***********************
		//i.设置排序信息
		example.orderBy("empSalary").asc().orderBy("empAge").desc();
		
		//ii.设置“去重”
		example.setDistinct(true);
		
		//iii.设置select字段
		example.selectProperties("empName","empSalary");
		
		//***********************
		
		//2.通过Example对象创建Criteria对象
		Criteria criteria01 = example.createCriteria();
		Criteria criteria02 = example.createCriteria();
		
		//3.在两个Criteria对象中分别设置查询条件
		//property参数：实体类的属性名
		//value参数：实体类的属性值
		criteria01.andGreaterThan("empSalary", 3000)
				  .andLessThan("empAge", 25);
		
		criteria02.andLessThan("empSalary", 5000)
				  .andGreaterThan("empAge", 30);
		
		//4.使用OR关键词组装两个Criteria对象
		example.or(criteria02);
		
		//5.执行查询
		List<Employee> empList = employeeService.getEmpListByExample(example);
		
		for (Employee employee : empList) {
			System.out.println(employee);
		}
	}

	

	@Test
	public void testSelectByRowBounds() {
		
		int pageNo = 3;
		int pageSize = 5;
		
		int index = (pageNo - 1) * pageSize;
		
		RowBounds rowBounds = new RowBounds(index, pageSize);
		
		List<Employee> empList = employeeService.getEmpListByRowBounds(rowBounds);
		for (Employee employee : empList) {
			System.out.println(employee);
		}
		
	}

}

 测试testInsert()方法：

原本5条数据，出入一条，返回id=6

 
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