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0817_mybatis简介

单表的crud操作【字段多一些】 employees表

条件查询
public List findByConds1(String firstname,String lastname,int minsalary,int maxlary);
public List findByConds2(Map map);
public List findByConds3(@Param(“firstname”)String firstname,@Param(“lastname”)String lastname,int minsalary,int maxlary);
public List findByConds4(EmployeesVo vo,int start,int pageSize);
动手能力强的同学，可以将之前的项目中的dao层更改为mybatis的实现。
结构:

Employees:

import lombok.Data;

import java.sql.Date;

@Data
public class Employees {
    private int employeeId;
    private String firstName;
    private String lastName;
    private String email;
    private String phoneNumber;
    private String jobId;
    private Double salary;
    private Double commissionPct;
    private Integer managerId;
    private Integer departmentId;
    private Date hiredate;

}

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Employeesvo:

import lombok.Data;

@Data
public class Employeesvo {
    private String firstName;
    private String lastName;
    private Integer minSalary;
    private Integer maxSalary;
}

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mybatis-config.xml:

DOCTYPE configuration
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    
        <settings>
            
            <setting name="logImpl" value="STDOUT_LOGGING"/>
            <setting name="mapUnderscoreToCamelCase" value="true" />
        settings>
        
    <typeAliases>
        <package name="com.cdcas.pojo"/>
    typeAliases>
    <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:///jspzzx?useSSl=false&serverTimezone=Asia/Shanghai&useServerPrepStmts=true"/>
                <property name="username" value="root"/>
                <property name="password" value="redhat"/>
            dataSource>
        environment>
    environments>
    <mappers>
        
        <package name="com.cdcas.mapper"/>
    mappers>
configuration>
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EmployeesMapper接口：

import com.cdcas.pojo.Employees;
import com.cdcas.pojo.Employeesvo;
import org.apache.ibatis.annotations.Param;

import java.util.List;
import java.util.Map;

public interface EmployeesMapper {

    List<Employees> findByConds1(String firstName, String lastName, int minSalary, int maxSalary);
    List<Employees> findByConds2(Map<String,Object> map);
    List<Employees> findByConds3(@Param("firstName") String firstName, @Param("lastName") String lastName, int minSalary, int maxSalary);
    List<Employees> findByConds4(Employeesvo vo, int start, int pageSize);
}

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EmployeesMapper.xml：

DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.cdcas.mapper.EmployeesMapper">



    <select id="findByConds1" resultType="com.cdcas.pojo.Employees">
    select * from employees where first_name like #{param1} and last_name like #{param2}
        and salary>=#{param3} and salary <=#{param4}
    select>
    <select id="findByConds2" resultType="com.cdcas.pojo.Employees">
        select * from employees where first_name like #{firstName} and last_name like #{lastName} 
        and salary>=#{minSalary} and salary <=#{maxSalary}
    select>
    <select id="findByConds3" resultType="com.cdcas.pojo.Employees">
        select * from employees where first_name like #{firstName} and last_name like #{lastName}
        and salary>=#{param3} and salary <=#{param4}
    select>
    <select id="findByConds4" resultType="com.cdcas.pojo.Employees">
        select * from employees where first_name like #{param1.firstName} and last_name like #{param1.lastName} 
        and salary>=#{param1.minSalary} and salary <=#{param1.maxSalary} limit #{param2}, #{param3}
    select>
mapper>
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之前的:

dao层和pojo单独抽成一个模块：

通过maven模块可以相互调用。和导入jar一样