springboot学习随笔（四）：Springboot整合mybatis（含generator自动生成代码）

这章我们将通过springboot整合mybatis来操作数据库

以下内容分为两部分，一部分主要介绍generator自动生成代码，生成model、dao层接口、dao接口对应的sql配置文件

第一部分：

1.修改的pom.xml，最终pom如下，添加了自动生成代码generator插件

<?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>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.20.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>
    <groupId>com.example</groupId>
    <artifactId>demo</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>Springboot</name>
    <description>Demo project for Spring Boot</description>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <!-- 整合mybatis -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.0</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            </dependency>

        <!-- 分页插件 -->
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper-spring-boot-starter</artifactId>
            <version>1.1.2</version>
        </dependency>

        <!-- druid连接池 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.1.0</version>
        </dependency>

    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
            <!-- mybatis generator 自动生成代码插件 -->
            <plugin>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.3.2</version>
                <configuration>
                    <configurationFile>${basedir}/src/main/resources/generator/generatorConfig.xml</configurationFile>
                    <overwrite>true</overwrite>
                    <verbose>true</verbose>
                </configuration>
            </plugin>
        </plugins>
    </build>

</project>

2.项目不使用application.properties文件 而使用更加简洁的application.yml文件：
将原有的resource文件夹下的application.properties文件删除，创建一个新的application.yml配置文件，
文件的内容如下：

server:
  port: 8080

spring:
    datasource:
        name: test
        url: jdbc:mysql://127.0.0.1:3306/mysql_test
        username: root
        password: root
        # 使用druid数据源
        type: com.alibaba.druid.pool.DruidDataSource
        driver-class-name: com.mysql.jdbc.Driver
        filters: stat
        maxActive: 20
        initialSize: 1
        maxWait: 60000
        minIdle: 1
        timeBetweenEvictionRunsMillis: 60000
        minEvictableIdleTimeMillis: 300000
        validationQuery: select 'x'
        testWhileIdle: true
        testOnBorrow: false
        testOnReturn: false
        poolPreparedStatements: true
        maxOpenPreparedStatements: 20

## 该配置节点为独立的节点，有很多同学容易将这个配置放在spring的节点下，导致配置无法被识别
mybatis:
  mapper-locations: classpath:mapping/*.xml  #注意：一定要对应mapper映射xml文件的所在路径
  type-aliases-package: com.example.model  # 注意：对应实体类的路径

#pagehelper分页插件
pagehelper:
    helperDialect: mysql
    reasonable: true
    supportMethodsArguments: true
    params: count=countSql

3.添加generator配置文件

在src/main/resources目录下，添加generator配置文件，路径：src/main/resources/generator/generatorConfig.xml

generatorConfig.xml如下：

注意：修改部分内容：

1.<classPathEntry  location="E:\devtools\repo\mysql\mysql-connector-java\5.1.24\mysql-connector-java-5.1.24.jar"/>
　　修改为实际的mysql-connect的jar包全路径（如果是本地仓库的，就写本地仓库的地址，如上就是我的本地仓库的jar包地址）

2.<jdbcConnection driverClass="com.mysql.jdbc.Driver" connectionURL="jdbc:mysql://127.0.0.1/mysql_test" userId="root" password="root">
　　修改为实际数据库ip，数据库名，账号，密码

3.<javaModelGenerator targetPackage="com.example.model" targetProject="src/main/java">
　　targetPackage修改为生成model的包名

4.<javaClientGenerator type="XMLMAPPER" targetPackage="com.example.mapper" targetProject="src/main/java">
　　targetPackage修改为生成mapper的包名

<?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="E:\devtools\repo\mysql\mysql-connector-java\5.1.24\mysql-connector-java-5.1.24.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.jdbc.Driver" connectionURL="jdbc:mysql://127.0.0.1/mysql_test" userId="root" password="root">
        </jdbcConnection>
        <javaTypeResolver>
            <property name="forceBigDecimals" value="false"/>
        </javaTypeResolver>
        <!-- 生成模型的包名和位置-->
        <javaModelGenerator targetPackage="com.example.model" targetProject="src/main/java">
            <property name="enableSubPackages" value="true"/>
            <property name="trimStrings" value="true"/>
        </javaModelGenerator>
        <!-- 生成映射文件的包名和位置-->
        <sqlMapGenerator targetPackage="mapping" targetProject="src/main/resources">
            <property name="enableSubPackages" value="true"/>
        </sqlMapGenerator>
        <!-- 生成DAO的包名和位置-->
        <javaClientGenerator type="XMLMAPPER" targetPackage="com.example.mapper" targetProject="src/main/java">
            <property name="enableSubPackages" value="true"/>
        </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="user" domainObjectName="User" enableCountByExample="false" enableUpdateByExample="false" enableDeleteByExample="false" enableSelectByExample="false" selectByExampleQueryId="false"></table>
    </context>
</generatorConfiguration>

4.在数据库中创建user表，

　　

5.根据表生成model、mapper、sqlmapper

右键项目，run-as，maven-build，下图框中输入：mybatis-generator:generate ,  执行run

6.执行成功后刷新项目，会发现自动生成了model、mapper、mapper.xml（如接着上章的操作，则删除之前的main\User.java）,最终目录如下

User.java对应了数据库中的user表

package com.example.model;

import java.io.Serializable;

public class User implements Serializable{
    /**
     *
     */
    private static final long serialVersionUID = 6308154504229603370L;

    private Long id;

    private String name;

    private Integer age;

    public Long getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name == null ? null : name.trim();
    }

    public Integer getAge() {
        return age;
    }

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

UserMapper.java 自动生成了dao层的增删改查接口

package com.example.mapper;

import com.example.model.User;

public interface UserMapper {
    int deleteByPrimaryKey(Long id);

    int insert(User record);

    int insertSelective(User record);

    User selectByPrimaryKey(Long id);

    int updateByPrimaryKeySelective(User record);

    int updateByPrimaryKey(User record);
}

UserMapper.xml则自动生成了UserMapper.java中接口对应的sql

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd" >
<mapper namespace="com.example.mapper.UserMapper" >
  <resultMap id="BaseResultMap" type="com.example.model.User" >
    <id column="id" property="id" jdbcType="BIGINT" />
    <result column="name" property="name" jdbcType="VARCHAR" />
    <result column="age" property="age" jdbcType="INTEGER" />
  </resultMap>
  <sql id="Base_Column_List" >
    id, name, age
  </sql>
  <select id="selectByPrimaryKey" resultMap="BaseResultMap" parameterType="java.lang.Long" >
    select
    <include refid="Base_Column_List" />
    from user
    where id = #{id,jdbcType=BIGINT}
  </select>
  <delete id="deleteByPrimaryKey" parameterType="java.lang.Long" >
    delete from user
    where id = #{id,jdbcType=BIGINT}
  </delete>
  <insert id="insert" parameterType="com.example.model.User" >
    insert into user (id, name, age)
    values (#{id,jdbcType=BIGINT}, #{name,jdbcType=VARCHAR}, #{age,jdbcType=INTEGER})
  </insert>
  <insert id="insertSelective" parameterType="com.example.model.User" >
    insert into user
    <trim prefix="(" suffix=")" suffixOverrides="," >
      <if test="id != null" >
        id,
      </if>
      <if test="name != null" >
        name,
      </if>
      <if test="age != null" >
        age,
      </if>
    </trim>
    <trim prefix="values (" suffix=")" suffixOverrides="," >
      <if test="id != null" >
        #{id,jdbcType=BIGINT},
      </if>
      <if test="name != null" >
        #{name,jdbcType=VARCHAR},
      </if>
      <if test="age != null" >
        #{age,jdbcType=INTEGER},
      </if>
    </trim>
  </insert>
  <update id="updateByPrimaryKeySelective" parameterType="com.example.model.User" >
    update user
    <set >
      <if test="name != null" >
        name = #{name,jdbcType=VARCHAR},
      </if>
      <if test="age != null" >
        age = #{age,jdbcType=INTEGER},
      </if>
    </set>
    where id = #{id,jdbcType=BIGINT}
  </update>
  <update id="updateByPrimaryKey" parameterType="com.example.model.User" >
    update user
    set name = #{name,jdbcType=VARCHAR},
      age = #{age,jdbcType=INTEGER}
    where id = #{id,jdbcType=BIGINT}
  </update>
</mapper>

以上是通过generator自动生成代码。是不是可以少些很多代码呀。。

接下来我们进入第二部分，开始操作数据库

第二部分：

1.修改SpringbootApplication.java启动类，添加mapper扫描包

2.编写通用返回类ResultModel

package com.example.demo.base;

import java.io.Serializable;

public class ResultModel<T> implements Serializable {

    /**
     *
     */
    private static final long serialVersionUID = -3045412214539024289L;
    private String resultCode;
    private String resultMsg;
    private T t;

    public String getResultCode() {
        return resultCode;
    }

    public void setResultCode(String resultCode) {
        this.resultCode = resultCode;
    }

    public String getResultMsg() {
        return resultMsg;
    }

    public void setResultMsg(String resultMsg) {
        this.resultMsg = resultMsg;
    }

    public T getT() {
        return t;
    }

    public void setT(T t) {
        this.t = t;
    }

}

3.编写Service层代码UserService.java（本次直接编写实现，不在分servicce接口和实现）

package com.example.demo.service;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import com.example.demo.base.ResultModel;
import com.example.mapper.UserMapper;
import com.example.model.User;

@Service
public class UserService {

    @Autowired
    private UserMapper userMapper;

    public ResultModel<User> insert(User user){
        ResultModel<User> rm = new ResultModel<User>();
        try {
            userMapper.insert(user);
        } catch (Exception e) {
            rm.setResultCode("9999999");
        }
        rm.setResultCode("0000000");
        rm.setResultMsg("新增成功");
        return rm;
    }
}

4.修改UserController.java

package com.example.demo.controller;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import com.example.demo.base.ResultModel;
import com.example.demo.service.UserService;
import com.example.model.User;

@RestController
@RequestMapping("/user")
public class UserController {

    @Autowired
    private UserService userService;

    @RequestMapping("/add")
    public ResultModel<User> user(User user){
        ResultModel<User> rm = userService.insert(user);
        return rm;
    }
}

5.在浏览器中访问，实现添加User

本章内容结束，如有疑问请留言