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最新推荐文章于 2023-03-04 21:44:02 发布

原创最新推荐文章于 2023-03-04 21:44:02 发布 · 248 阅读

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CC 4.0 BY-SA版权

本文详细介绍了如何在SpringBoot项目中集成MyBatis，包括解决常见问题如pom依赖配置、资源文件命名、Mapper扫描配置等，以及如何通过MyBatis Generator自动生成DAO层代码。

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坑一:pom文件依赖标红

解决：在前面的dependency依赖里加进去

坑二：

运行时出错：Failed to determine a suitable driver class

原因：resources文件夹命名错误，必须为resources。修改之后重新打包——run——edit configuration

Run——run——选择如下图所示选项

结果生成：

回顾第一步：

新建工程maven——create from archi——

目录结构：

1、mybatis-generator.xml要在resources下，不能放在mapping包里，否则启动会报空指针。

2、为什么在配置文件里配置路径：

原因：

如果Mapper.xml与Mapper.class在同一个包下且同名，spring扫描Mapper.class的同时会自动扫描同名的Mapper.xml并装配到Mapper.class。

如果Mapper.xml与Mapper.class不在同一个包下或者不同名，就必须使用配置mapperLocations指定mapper.xml的位置。

此时spring是通过识别mapper.xml中的 <mapper namespace="com.fan.mapper.UserDao"> namespace的值来确定对应的Mapper.class的。

<?xml version="1.0" encoding="UTF-8"?>

<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.miaosha.project</groupId>
  <artifactId>miaosha</artifactId>
  <version>1.0-SNAPSHOT</version>

  <name>miaosha</name>
  <!-- FIXME change it to the project's website -->
  <url>http://www.example.com</url>

  <parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>2.0.5.RELEASE</version>
  </parent>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <maven.compiler.source>1.7</maven.compiler.source>
    <maven.compiler.target>1.7</maven.compiler.target>
  </properties>

  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>5.1.41</version>
    </dependency>
    <dependency>
      <groupId>com.alibaba</groupId>
      <artifactId>druid</artifactId>
      <version>1.1.3</version>
    </dependency>
    <dependency>
      <groupId>org.mybatis.spring.boot</groupId>
      <artifactId>mybatis-spring-boot-starter</artifactId>
      <version>1.3.1</version>
    </dependency>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>
    <dependency>
      <groupId>org.mybatis.generator</groupId>
      <artifactId>mybatis-generator-core</artifactId>
      <version>1.3.5</version>
    </dependency>
  </dependencies>

  <build>
    <pluginManagement><!-- lock down plugins versions to avoid using Maven defaults (may be moved to parent pom) -->
      <plugins>
        <!-- clean lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#clean_Lifecycle -->
        <plugin>
          <artifactId>maven-clean-plugin</artifactId>
          <version>3.1.0</version>
        </plugin>
        <!-- default lifecycle, jar packaging: see https://maven.apache.org/ref/current/maven-core/default-bindings.html#Plugin_bindings_for_jar_packaging -->
        <plugin>
          <artifactId>maven-resources-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-compiler-plugin</artifactId>
          <version>3.8.0</version>
        </plugin>
        <plugin>
          <artifactId>maven-surefire-plugin</artifactId>
          <version>2.22.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-jar-plugin</artifactId>
          <version>3.0.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-install-plugin</artifactId>
          <version>2.5.2</version>
        </plugin>
        <plugin>
          <artifactId>maven-deploy-plugin</artifactId>
          <version>2.8.2</version>
        </plugin>
        <!-- site lifecycle, see https://maven.apache.org/ref/current/maven-core/lifecycles.html#site_Lifecycle -->
        <plugin>
          <artifactId>maven-site-plugin</artifactId>
          <version>3.7.1</version>
        </plugin>
        <plugin>
          <artifactId>maven-project-info-reports-plugin</artifactId>
          <version>3.0.0</version>
        </plugin>
          <plugin>
            <groupId>org.mybatis.generator</groupId>
              <artifactId>mybatis-generator-maven-plugin</artifactId>
              <version>1.3.5</version>
              <dependencies>
                <dependency>
                  <groupId>org.mybatis.generator</groupId>
                  <artifactId>mybatis-generator-core</artifactId>
                  <version>1.3.5</version>
                </dependency>
                <dependency>
                  <groupId>mysql</groupId>
                  <artifactId>mysql-connector-java</artifactId>
                  <version>5.1.41</version>
                </dependency>
              </dependencies>
            <executions>
              <execution>
                <id>mybatis generator</id>
                <phase>package</phase>
                <goals>
                  <goal>generate</goal>
                </goals>
              </execution>
            </executions>
            <configuration>
              <verbose>true</verbose>
              <overwrite>true</overwrite>
              <configurationFile>
                src/main/resources/mybatis-generator.xml
              </configurationFile>
            </configuration>
          </plugin>
      </plugins>
    </pluginManagement>
  </build>
</project>

package com.miaosha.project;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;

/**
 * Hello world!
 *
 */
@EnableAutoConfiguration

@SpringBootApplication(exclude= {DataSourceAutoConfiguration.class})
public class App 
{
    public static void main( String[] args )
    {

        System.out.println( "Hello World!" );
        SpringApplication.run(App.class,args);
    }
}

server.port=8090
mybatis.mapper-locations=classpath:mapping/*.xml

<?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>
    <context id="DB2Tables" targetRuntime="MyBatis3">
        <!--数据库连接地址和密码-->
        <jdbcConnection driverClass="com.mysql.jdbc.Driver"
                        connectionURL="jdbc:mysql://127.0.0.1:3306/miaosha"
                        userId="root"
                        password="root">
        </jdbcConnection>
        <!--存放DataObject类的地址 -->
        <javaModelGenerator targetPackage="com.miaosha.project.dataObject"
                            targetProject="src/main/java">
            <property name="enableSubPackages" value="true" />
            <property name="trimStrings" value="true" />
        </javaModelGenerator>
        <!--生成映射文件资源位置-->
        <sqlMapGenerator targetPackage="mapping"  targetProject="src/main/resources">
            <property name="enableSubPackages" value="true" />
        </sqlMapGenerator>
        <!--生成Dao存放位置-->
        <javaClientGenerator type="XMLMAPPER" targetPackage="com.miaosha.project.dao"
                             targetProject="src/main/java">
            <property name="enableSubPackages" value="true" />
        </javaClientGenerator>

        <table tableName="user_info" domainObjectName="UserDO" enableCountByExample="false"
        enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="false"
        selectByExampleQueryId="false">
        </table>
        <table tableName="user_password" domainObjectName="UserPasswordDO" enableCountByExample="false"
               enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="false"
               selectByExampleQueryId="false"></table>

    </context>
</generatorConfiguration>

删除example的只剩下如图：

第二步：

1、配置文件新增：

ing.datasource.name=miaosha
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/miaosha?useUnicode=true&characterEncoding=utf-8&useSSL=true
spring.datasource.username=root
spring.datasource.password=root

#使用druid数据源
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

2、修改APP.class为如图

SpringApplication.run(App.class,args);

package com.miaosha.project;

import com.miaosha.project.dao.UserDOMapper;
import com.miaosha.project.dataObject.UserDO;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

/**
 * Hello world!
 *
 */


@SpringBootApplication
@RestController
@MapperScan("com.miaosha.project.dao")
public class App {
    @Autowired
    private UserDOMapper userDOMapper;
   @RequestMapping("/1")
    public String home(){
        UserDO userDO = userDOMapper.selectByPrimaryKey(1);
        if(userDO == null){
            return "用户信息不存在";
        }else{
            return userDO.getName();
        }
    }

    public static void main( String[] args )
    {

        System.out.println( "Hello World!" );
        SpringApplication.run(App.class,args);
    }
}

坑三：一开始访问不到：404

应该是没有扫描到，可能和左侧目录结构有关

丢掉了RestController注解

三、

新增

package com.miaosha.project.service;

import com.miaosha.project.service.model.UserModel;

public interface UserService {
    UserModel getUserById(Integer id);
}

package com.miaosha.project.service.impl;

import com.miaosha.project.dao.UserDOMapper;
import com.miaosha.project.dao.UserPasswordDOMapper;
import com.miaosha.project.dataObject.UserDO;
import com.miaosha.project.dataObject.UserPasswordDO;
import com.miaosha.project.service.UserService;
import com.miaosha.project.service.model.UserModel;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

@Service
public class UserServiceImpl implements UserService {
    @Autowired
    private UserDOMapper userDOMapper;
    @Autowired
    private UserPasswordDOMapper userPasswordDOMapper;
    @Override
    public UserModel getUserById(Integer id) {
        UserDO userDO = userDOMapper.selectByPrimaryKey(id);
        if(userDO == null){
            return null;
        }
        //通过用户id获取用户加密信息
        UserPasswordDO userPasswordDO = userPasswordDOMapper.selectByUserId(userDO.getId());
        return convertFromDataObject(userDO,userPasswordDO);
    }
    private UserModel convertFromDataObject(UserDO userDO, UserPasswordDO userPasswordDO){
        if(userDO == null){
            return null;
        }
        UserModel userModel = new UserModel();
        BeanUtils.copyProperties(userDO,userModel);
        if(userPasswordDO != null){
            userModel.setEncrptPassword(userPasswordDO.getEncrptPassword());
        }
        return userModel;
    }

}

package com.miaosha.project.service.model;

public class UserModel {
    private Integer id;
    private String name;
    private Byte gender;
    private Integer age;
    private String telphone;
    private String risterMode;
    private String thirdPartyId;
    private String encrptPassword;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Byte getGender() {
        return gender;
    }

    public void setGender(Byte gender) {
        this.gender = gender;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public String getTelphone() {
        return telphone;
    }

    public void setTelphone(String telphone) {
        this.telphone = telphone;
    }

    public String getRisterMode() {
        return risterMode;
    }

    public void setRisterMode(String risterMode) {
        this.risterMode = risterMode;
    }

    public String getThirdPartyId() {
        return thirdPartyId;
    }

    public void setThirdPartyId(String thirdPartyId) {
        this.thirdPartyId = thirdPartyId;
    }

    public String getEncrptPassword() {
        return encrptPassword;
    }

    public void setEncrptPassword(String encrptPassword) {
        this.encrptPassword = encrptPassword;
    }
}

新增内容UserPasswordDOMapper.xml：


<sql id="Base_Column_List">

    id,encrpt_password,user_id
  </sql>
  <select id="selectByUserId" parameterType="java.lang.Integer" resultMap="BaseResultMap">
    select
    <include refid="Base_Column_List" />
    from user_password
    where user_id = #{userId,jdbcType=INTEGER}
  </select>

package com.miaosha.project.controller;

import com.miaosha.project.service.UserService;
import com.miaosha.project.service.model.UserModel;
import com.sun.org.apache.xpath.internal.operations.Mod;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller("user")
@RequestMapping("/user")
public class UserController {
    @Autowired
    private UserService userService;
    @RequestMapping("/get")
    @ResponseBody
    public UserModel getUser(@RequestParam("id") Integer id){
        UserModel userModel = userService.getUserById(id);
        return userModel;
    }
}

package com.miaosha.project.dao;

import com.miaosha.project.dataObject.UserPasswordDO;

public interface UserPasswordDOMapper {
    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table user_password
     *
     * @mbg.generated Tue Jan 08 17:11:48 CST 2019
     */
    int insert(UserPasswordDO record);

    /**
     * This method was generated by MyBatis Generator.
     * This method corresponds to the database table user_password
     *
     * @mbg.generated Tue Jan 08 17:11:48 CST 2019
     */
    int insertSelective(UserPasswordDO record);

    UserPasswordDO selectByUserId(Integer userId);
}

访问：

新增：返回前端的对象

package com.miaosha.project.controller.viewObject;

public class UserVo {
    private Integer id;
    private String name;
    private Byte gender;
    private Integer age;
    private String telphone;

    public Integer getId() {
        return id;
    }

    public void setId(Integer id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Byte getGender() {
        return gender;
    }

    public void setGender(Byte gender) {
        this.gender = gender;
    }

    public Integer getAge() {
        return age;
    }

    public void setAge(Integer age) {
        this.age = age;
    }

    public String getTelphone() {
        return telphone;
    }

    public void setTelphone(String telphone) {
        this.telphone = telphone;
    }
}

package com.miaosha.project.controller;

import com.miaosha.project.controller.viewObject.UserVo;
import com.miaosha.project.service.UserService;
import com.miaosha.project.service.model.UserModel;
import com.sun.org.apache.xpath.internal.operations.Mod;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;

@Controller("user")
@RequestMapping("/user")
public class UserController {
    @Autowired
    private UserService userService;
    @RequestMapping("/get")
    @ResponseBody
    public UserVo getUser(@RequestParam("id") Integer id){
        UserModel userModel = userService.getUserById(id);
        return convertFromUserModel(userModel);
    }
    private UserVo convertFromUserModel(UserModel userModel){
        if(userModel == null){
            return null;
        }
        UserVo userVo = new UserVo();
        //字段名以及类型均一致
        BeanUtils.copyProperties(userModel,userVo);
        return userVo;
    }
}

访问：