spring集成mybaits以注解方式完成连表查询练习
题目：
以注解的方式完成连表查询
1、查询全部员工信息，要求显示部门名称
2、根据姓名模糊查询员工信息
自己看完，建一个简单的员工表和部门表。
1、先创建一个maven模块，这里直接建的普通maven模块，你也可以用quickStart骨架
2、引入必要的依赖
junit
junit
4.12
test
mysql
mysql-connector-java
8.0.24
com.alibaba
druid
1.2.4
org.mybatis
mybatis
3.5.6
org.springframework
spring-context
5.3.22
org.springframework
spring-jdbc
5.3.3
org.mybatis
mybatis-spring
2.0.5
别忘了刷新
3、 创建实体类
Employee
package com.gc.bean;
public class Employee {
private Integer emId; //员工ID
private String emName; //员工姓名
private String emAddress;//员工地主之
private Dept dept; //所在部门
public Employee(){}
public Employee(Integer emId, String emName, String emAddress, Dept dept) {
this.emId = emId;
this.emName = emName;
this.emAddress = emAddress;
this.dept = dept;
}
public Integer getEmId() {
return emId;
}
public void setEmId(Integer emId) {
this.emId = emId;
}
public String getEmName() {
return emName;
}
public void setEmName(String emName) {
this.emName = emName;
}
public String getEmAddress() {
return emAddress;
}
public void setEmAddress(String emAddress) {
this.emAddress = emAddress;
}
public Dept getDept() {
return dept;
}
public void setDept(Dept dept) {
this.dept = dept;
}
@Override
public String toString() {
return "Employee{" +
"emId=" + emId +
", emName='" + emName + '\'' +
", emAddress='" + emAddress + '\'' +
", dept=" + dept +
'}';
}
}
Dept
package com.gc.bean;
public class Dept {
private Integer deptId; //部门编号
private String deptName;//部门名称
public Dept(){}
public Dept(Integer deptId, String deptName) {
this.deptId = deptId;
this.deptName = deptName;
}
public Integer getDeptId() {
return deptId;
}
public void setDeptId(Integer deptId) {
this.deptId = deptId;
}
public String getDeptName() {
return deptName;
}
public void setDeptName(String deptName) {
this.deptName = deptName;
}
@Override
public String toString() {
return "Dept{" +
"deptId=" + deptId +
", deptName='" + deptName + '\'' +
'}';
}
}
4、创建Dao接口
EmployeeDao
package com.gc.dao;
import com.gc.bean.Dept;
import com.gc.bean.Employee;
import org.apache.ibatis.annotations.*;
import java.util.List;
public interface EmployeeDao {
/**
* 1、查询全部员工信息
* @return
*/
@Select("select * from employee")
@Results({
@Result(column = "emId",property = "emId"),
@Result(column = "emName",property = "emName"),
@Result(column = "emAddress",property = "emAddress"),
@Result(
property = "dept",
column = "deptId",
javaType = Dept.class,
one = @One(select = "com.gc.dao.DeptDao.selectByName")
)
})
List selectAll();
/**
* 2、根据姓名模糊查询员工信息
* @return
*/
@Select("select * from employee where emName like concat('%',#{name},'%')")
@Results({
@Result(column = "emId",property = "emId"),
@Result(column = "emName",property = "emName"),
@Result(column = "emAddress",property = "emAddress"),
@Result(
property = "dept",
column = "deptId",
javaType = Dept.class,
one = @One(select = "com.gc.dao.DeptDao.selectByName")
)
})
List selectByName(String name);
}
DeptDao
package com.gc.dao;
import com.gc.bean.Dept;
import org.apache.ibatis.annotations.Select;
public interface DeptDao {
/**
* 根据dpetId查询部门对象
* @return
*/
@Select("select * from Dept where deptId=#{deptId}")
Dept selectByName(Integer id);
}5、创建Service接口和实现类
package com.gc.service;
import com.gc.bean.Employee;
import java.util.List;
public interface EmployeeService {
List selectAll();
List selectByName(String name);
}
package com.gc.service.impl;
import com.gc.bean.Employee;
import com.gc.dao.EmployeeDao;
import com.gc.service.EmployeeService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
import java.util.List;
@Component("employeeService") //将类的对象生成Bean，交给IOC容器管理
public class EmployeeServiceImpl implements EmployeeService {
@Autowired //将Dao接口对象生成Bean，交由IOC容器管理
private EmployeeDao employeeDao;
@Override
public List selectAll() {
return employeeDao.selectAll();
}
@Override
public List selectByName(String name) {
return employeeDao.selectByName(name);
}
}
6、配置数据源、配置Mybatis(替代MybatisConfig.xml)和配置Spring(替代applicationContext.xml)
1）配置文件(db.properties)
jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql:///mybatis_DB?characterEncoding=utf-8
jdbc.username=root
jdbc.password=1234
2）配置数据源(jdbcDataSource)
package com.gc.config;
import com.alibaba.druid.pool.DruidDataSource;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
public class jdbcDataSource {
@Value("${jdbc.driver}") //给属性赋值
private String driver;
@Value("${jdbc.url}")
private String url;
@Value("${jdbc.username}")
private String userName;
@Value("${jdbc.password}")
private String password;
@Bean("dataSource") //将方法返回的对象生成Bean，交给IOC容器管理
public DruidDataSource getDataSource(){
DruidDataSource dataSource = new DruidDataSource();
dataSource.setDriverClassName(driver);
dataSource.setUrl(url);
dataSource.setUsername(userName);
dataSource.setPassword(password);
return dataSource;
}
}
3)配置Mybatis
package com.gc.config;
import com.alibaba.druid.pool.DruidDataSource;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.mapper.MapperScannerConfigurer;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
public class MybatisConfig {
@Bean
public SqlSessionFactoryBean getFactory(@Autowired DruidDataSource dataSource){
SqlSessionFactoryBean factoryBean = new SqlSessionFactoryBean();
factoryBean.setDataSource(dataSource);
//factoryBean.setTypeAliasesPackage("com.gc.bean"); //设置别名
return factoryBean;
}
@Bean
public MapperScannerConfigurer getMapperScannerConfigurer(){
MapperScannerConfigurer configurer = new MapperScannerConfigurer();
configurer.setBasePackage("com.gc.dao"); //扫描指定包
return configurer;
}
}
4）配置Spring
package com.gc.config;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Import;
import org.springframework.context.annotation.PropertySource;
@Configuration //将类设置为核心配置类
@ComponentScan("com.gc")//扫描只当包类上的注解
@PropertySource("classpath:db.properties") //读取根目录下的db.properties配置文件
@Import({jdbcDataSource.class,MybatisConfig.class}) //导入jdbcDataSource类和MybatisConfig类
public class SpringConfig {
}
7、测试
package com.gc.test;
import com.gc.bean.Employee;
import com.gc.config.SpringConfig;
import com.gc.service.EmployeeService;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import java.util.List;
public class EmployeeTest {
//返回EmployeeService对象
public EmployeeService getService(){
//加载核心配置类
ApplicationContext cxt = new AnnotationConfigApplicationContext(SpringConfig.class);
return (EmployeeService) cxt.getBean("employeeService");
}
@Test
public void SelectAll(){
List employeeList = getService().selectAll();
for(Employee employee:employeeList){
System.out.println(employee);
}
}
@Test
public void selectByName(){
List employeeList = getService().selectByName("2");
for(Employee employee:employeeList){
System.out.println(employee);
}
}
}
最后看下，我的目录结构
博主正处于学习spring阶段，有一起学习的可以和我交流。冲冲冲