3、依赖配置 Spring Boot+Mybatis

依赖配置

结合前面的内容，这里我们要嵌入数据库的操作，这里以操作mysql为例整合Mybatis，首先需要在原来的基础上添加以下依赖

<!-- mybatis依赖 -->
<dependency>
    <groupId>org.mybatis.spring.boot</groupId>
    <artifactId>mybatis-spring-boot-starter</artifactId>
    <version>1.1.1</version>
</dependency>

当然啦，只依赖mybatis是不够的还需要依赖jdbc驱动以及返回json数据的json库(格式化数据)

<!-- MySql驱动 -->
<dependency>
    <groupId>org.apache.tomcat</groupId>
    <artifactId>tomcat-jdbc</artifactId>
</dependency>
<dependency>
    <groupId>mysql</groupId>
    <artifactId>mysql-connector-java</artifactId>
    <version>5.1.21</version>
</dependency>

<!--Json库的依赖 -->
    <dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.1.43</version>
</dependency>

应用配置

接着需要在application.properties中添加数据库配置

#JDBC配置
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/weibo?useUnicode=true&characterEncoding=utf-8&zeroDateTimeBehavior=convertToNull
spring.datasource.username=root
spring.datasource.password=root
spring.datasource.driver-class-name=com.mysql.jdbc.Driver

这里连接的数据库名叫weibo，其中表结构如下：

接下来就需要来具体的初始化MyBatis配置以及数据表的操作了，先看一下工程结构

编写配置类

数据库相关的DataSource，SqlSeesion配置，其中DataSourse的配置可以理解为解读application.properties中的jdbc相关配置然后初始化JDBC驱动的，SqlSeesion配置主要是针对Mybatis使用事务操作时的配置信息。

package com.example.demo.config;

import javax.sql.DataSource;

import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import org.springframework.transaction.PlatformTransactionManager;

@EnableAutoConfiguration
@ComponentScan
@MapperScan("com.example.demo.mapper")
public class JdbcConfig {
    // DataSource配置
    @Bean
    @ConfigurationProperties(prefix = "spring.datasource")
    public DataSource dataSource() {
        return new org.apache.tomcat.jdbc.pool.DataSource();
    }

    // 提供SqlSeesion(数据库事务操作相关的配置)
    @Bean
    public SqlSessionFactory sqlSessionFactoryBean() throws Exception {
        SqlSessionFactoryBean sqlSessionFactoryBean = new SqlSessionFactoryBean();
        sqlSessionFactoryBean.setDataSource(dataSource());
        PathMatchingResourcePatternResolver resolver = new PathMatchingResourcePatternResolver();
        sqlSessionFactoryBean.setMapperLocations(resolver.getResources("classpath:/mybatis/*.xml"));
        return sqlSessionFactoryBean.getObject();
    }

    @Bean
    public PlatformTransactionManager transactionManager() {
        return new DataSourceTransactionManager(dataSource());
    }
}

pom.xml配置中要添加配置解析组件

org.springframework.boot
spring-boot-configuration-processor
true

添加Pojo类

该类主要接收数据表中的数据，所以属性基本上跟数据表的属性一致

package com.example.demo.bean;

public class Diary {
    private int id;
    private String title;
    private String content;
    private String pubTime;
    private int userId;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getTitle() {
        return title;
    }
    public void setTitle(String title) {
        this.title = title;
    }
    public String getContent() {
        return content;
    }
    public void setContent(String content) {
        this.content = content;
    }
    public String getPubTime() {
        return pubTime;
    }
    public void setPubTime(String pubTime) {
        this.pubTime = pubTime;
    }
    public int getUserId() {
        return userId;
    }
    public void setUserId(int userId) {
        this.userId = userId;
    }
    @Override
    public String toString() {
        return "Diary [id=" + id + ", title=" + title + ", content=" + content + ", pubTime=" + pubTime + ", userId="
                + userId + "]";
    }

}

添加数据表操作接口

该类描述了操作数据表的过程，SprintBoot在运行中会根据类上的@Mapper注解找到它，因此不能落下这个注解

package com.example.demo.mapper;

import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;
import org.apache.ibatis.annotations.Select;

import com.example.demo.bean.Diary;

@Mapper
public interface DiaryMapper {

    @Select("select * from diary where _id = #{id}")
    public Diary getDiaryById(@Param("id")Integer id);
}

使用

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.alibaba.fastjson.JSON;
import com.example.demo.bean.Diary;
import com.example.demo.mapper.DiaryMapper;

@RestController
public class DiaryMappingController {
    @Autowired
    DiaryMapper diaryMapper;

    @RequestMapping("/diary")
    public String getDiary(Integer id){
        Diary d = diaryMapper.getDiaryById(id);
        String json = JSON.toJSONString(d);
        return json;
    }
}

最后运行SpringBoot项目，然后在浏览器上输入网址：
http://localhost:8080/diary?id=2
这样即可看到结果