Spring Boot project 第二篇-实训项目day2

1.搭建环境：idea+MySQL数据库+Mybatis

2.mybatis的自动生成

2.1在pom.xml文件中导入插件

<plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
                <configuration>
                    <excludes>
                        <exclude>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                        </exclude>
                    </excludes>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.3.5</version>
                <configuration>
                    <configurationFile>${basedir}/src/main/resources/generator/generatorConfig.xml</configurationFile>
                    <overwrite>true</overwrite>
                    <verbose>true</verbose>
                </configuration>
            </plugin>

        </plugins>

<configurationFile>标签中存放自动生成的配置文件的.xml文件，${basedir}只起到引导作用，表示绝对地址，配置文件名称：generatorConfig.xml

其次要注意版本问题

 <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.4.3</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

  <plugin>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.3.5</version>
                <configuration>
                    <configurationFile>${basedir}/src/main/resources/generator/generatorConfig.xml</configurationFile>
                    <overwrite>true</overwrite>
                    <verbose>true</verbose>
                </configuration>
            </plugin>

2.2 配置generatorConfig.xml文件

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE generatorConfiguration
        PUBLIC "-//mybatis.org//DTD MyBatis Generator Configuration 1.0//EN"
        "http://mybatis.org/dtd/mybatis-generator-config_1_0.dtd">

<generatorConfiguration>
    <!-- 数据库驱动:选择你的本地硬盘上面的数据库驱动包-->
    <classPathEntry  location="D:\JDK\MySQL\mysql-connector-java-8.0.12.jar"/>
    <context id="DB2Tables"  targetRuntime="MyBatis3">
        <commentGenerator>
            <property name="suppressDate" value="true"/>
            <!-- 是否去除自动生成的注释 true：是 ： false:否 -->
            <property name="suppressAllComments" value="true"/>
        </commentGenerator>
        <!--数据库链接URL，用户名、密码 -->
        <jdbcConnection driverClass="com.mysql.cj.jdbc.Driver" connectionURL="jdbc:mysql://localhost:3306/test?useSSL=false&amp;serverTimezone=UTC" userId="root" password="123456">
        </jdbcConnection>
        <javaTypeResolver>
            <property name="forceBigDecimals" value="false"/>
        </javaTypeResolver>
        <!-- 生成模型的包名和位置-->
        <javaModelGenerator targetPackage="com.example.springboot1.model" targetProject="src/main/java">
        </javaModelGenerator>
        <!-- 生成映射文件的包名和位置-->
        <sqlMapGenerator targetPackage="mapping/generated" targetProject="src/main/resources">
        </sqlMapGenerator>
        <!-- 生成DAO的包名和位置-->
        <javaClientGenerator type="XMLMAPPER" targetPackage="com.example.springboot1.dao" targetProject="src/main/java">
        </javaClientGenerator>
        <!-- 要生成的表 tableName是数据库中的表名或视图名 domainObjectName是实体类名-->
      <!--  <table tableName="account" domainObjectName="Account" mapperName="AccountDAO" >
        </table>
        <table tableName="person" domainObjectName="Person" mapperName="PersonDAO" >
        </table>-->
        <table tableName="user" domainObjectName="User" mapperName="UserDAO"  catalog="test">
        </table>

    </context>
</generatorConfiguration>

注：

1.classPathEntry标签导入一个数据库驱动，选择你的本地硬盘上面的数据库驱动包

2.javaModelGenerator生成模型的包名和位置，即model

3.sqlMapGenerator生成映射文件的包名和位置

4.javaClientGenerator生成DAO的包名和位置

<table tableName="user" domainObjectName="User" mapperName="UserDAO"  catalog="test">
        </table>

tablename指定数据库表，domainObjectName指定数据对象类型，mapperName映射DAO类的名称，当多个数据库有同一个表时，需要用catalog指定数据库。

 <table tableName="user" domainObjectName="User" mapperName="UserDAO"
               catalog="test">
            <property name="ignoreQualifiersAtRuntime" value="true"/>
        </table>

可以解决自动生成文件的两个点的问题

3.实现分页查询和模糊查询

3.1.实现用来映射的DTO文件

package com.example.springboot1.dto;

import lombok.Data;
import org.springframework.stereotype.Component;

@Data
@Component
public class UserDTO {
    private Integer id;

    private String username;

    private String password;

    private String nickname;

    private String phone;

    private Integer age;

    private Integer pageNum;  //页码
    private Integer startNum;  //查询开始位置
    private Integer pageSize;  //每页条数
}

其中页码，查询开始位置，每页条数是用来分页的，前面的属性用来做数据库映射。

3.2.编写UserSpecDAO.xml文件

 <select id="getUserByParam" resultType="User">
        select *
        from user
        where 1=1
        <if test="username != null">
            and username like "%"#{username}"%"
        </if>
        <if test="nickname != null">
            and username like "%"#{nickname}"%"
        </if>
        <if test="phone != null">
            and phone = #{phone}
        </if>
        <if test="age != null">
            and age = #{age}
        </if>
        limit #{startNum},#{pageSize}
    </select>

3.3编写UserService接口

package com.example.springboot1.service;


import com.example.springboot1.dto.UserDTO;
import com.example.springboot1.model.User;


import java.util.List;


public interface UserService {
    User login(User user);
    int reg(User user);
   // int update(User user);
    List<User> getAllUser();
    public List<UserDTO> getUserByParam(UserDTO userDTO);

}

3.4编写实现类方法

package com.example.springboot1.service.impl;

import com.example.springboot1.dao.UserDAO;
import com.example.springboot1.dao.UserSpecDAO;
import com.example.springboot1.dto.UserDTO;
import com.example.springboot1.model.User;
import com.example.springboot1.model.UserExample;
import com.example.springboot1.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;
@Service
public class UserServiceImpl implements UserService {
    @Autowired
    UserSpecDAO userSpecDAO;
    @Autowired
    UserDAO userDAO;
    @Autowired
    UserDTO userDTO;

    @Override
    public User login(User user) {
        List <User> users = userSpecDAO.login ( user );
        return users.get ( 0 );
    }

    @Override
    public int reg(User user) {
        return userDAO.insertSelective ( user );
    }

    @Override
    public List <User> getAllUser() {
        UserExample userExample = new UserExample();
        return userDAO.selectByExample(userExample);
    }

    @Override
    public List <UserDTO> getUserByParam(UserDTO userDTO) {
        userDTO.setStartNum((userDTO.getPageNum()-1)*userDTO.getPageSize());
        return userSpecDAO.getUserByParam(userDTO);
    }



   /* @Override
    public int update(User user) {
       // System.out.println ( userDAO.updateByExample (  ) );
        return userDAO.updateByPrimaryKey ( user );
    }*/
}

3.5 编写UserSpecDAO接口

package com.example.springboot1.dao;

import com.example.springboot1.dto.UserDTO;
import com.example.springboot1.model.User;
import org.springframework.stereotype.Repository;

import java.util.List;
@Repository
public interface UserSpecDAO {
    List<User> login(User user);
    List<User>  getAllUser();
    List<UserDTO> getUserByParam(UserDTO userDTO);
}

3.6.crotroller层方法

    @PostMapping("/getUserByParam")
    @ResponseBody
    public ResultModel getUserByParam(@RequestBody UserDTO userDTO){
        //@RequestBody在形参中表示用来接收参数
        if(null == userDTO.getPageNum()){
            return ResultModel.error("页码必传");
        }
        if(null == userDTO.getPageSize()){
            return ResultModel.error("长度必传");
        }
        return ResultModel.success(userService.getUserByParam(userDTO));
    }

3.7.postman查询

附：目录结构：