架构实战篇（一）：Spring Boot 整合MyBatis

Spring的追求一定是简单点简单点，让java的开发变得更加简单、容易。Spring boot就是朝着这一追求更近了一步的天使，一个在Spring基础上的一整套实现。

期初，对Spring boot没有太多的好感，觉得它只不过是把java企业级应用必须用的servlet容器给干掉了而已。

进一步接触，才有所感悟，原来Spring boot是这么强大的一个东西。像boot这个名字和它的图标一样，就像是一台电脑的启动按钮，当你start之后，所有你需要的东西都准别好了。你需要做的，就是尽情享受现代科技的美妙。

下面就跟着我去搭建一个Spring Boot整合MyBatis的例子吧

默认这些东西都是需要有的： Jdk1.6+，Maven，MySql数据库

我们先看下已经完成的项目结构图

项目结构

最终运行结果

调用结果

下面开始一步一步的编写代码了

增加Spring boot的maven 依赖

继承spring boot 父类

    
        org.springframework.boot
        spring-boot-starter-parent
        1.5.1.RELEASE

增加依赖项


        
            org.springframework.boot
            spring-boot-starter-web
        
        
            org.springframework.boot
            spring-boot-starter-data-jpa
        
        
            org.apache.tomcat.embed
            tomcat-embed-jasper
        
        
        
            org.mybatis
            mybatis
            3.4.2
        
        
        
            org.mybatis
            mybatis-spring
            1.3.1
        
        
        
            mysql
            mysql-connector-java
        
        
        
            com.alibaba
            druid
            1.0.27
        
        
        
            com.github.pagehelper
            pagehelper
            
            4.1.6
        
        
        
            org.springframework.boot
            spring-boot-starter-tomcat
            provided
        
    
    war
    
    
        1.8
    
    
        
        demo
        
            
                org.springframework.boot
                spring-boot-maven-plugin
            
            
            
                org.apache.maven.plugins
                maven-war-plugin
                2.1.1
                
                    false

增加主要的入口类和配置

文件的位置

Application.java

package com.yundian;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
@SpringBootApplication
@RestController
public class Application {
    @RequestMapping("/")
    public String index() {
        return "Hello Spring Boot";
    }
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

application.properties

server.port=8080
server.context-path=/demo

我们先运行下看看效果吧

在Application.java 类中右键运行

启动成功了

使用IDE工具测试下吧

Tools > Test Restful Web Service

运行

或者在浏览器地址栏访问

http://localhost:8080/demo

下面整合MyBatis

首先补充上完整的application.properties 配置内容包含了数据库的配置

记得修改你自己的数据库账号和密码

server.port=8080
server.context-path=/demo
druid.driver=com.mysql.jdbc.Driver
druid.url=jdbc:mysql://localhost:3306/mysql
druid.username=root
druid.password=123456
druid.init-size=1
druid.min-idel=1
druid.max-active=5
druid.login.timeout.seconds=30
druid.query.timeout.seconds=30

resources/mybatis-config.xml

注意了！注意了！每次增加xml配置记得要在这里增加mapper配置

这里我们写一个简单的查询语句

resources/mappers/HelpCategoryMapper.xml

com.yundian.configuration.DatasourceConfig.java

package com.yundian.configuration;
import com.alibaba.druid.pool.DruidDataSource;
import org.apache.ibatis.session.SqlSessionFactory;
import org.mybatis.spring.SqlSessionFactoryBean;
import org.mybatis.spring.annotation.MapperScan;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.ClassPathResource;
import org.springframework.jdbc.datasource.DataSourceTransactionManager;
import javax.sql.DataSource;

@Configuration
@MapperScan(basePackages = "com.yundian.mapper")
public class DatasourceConfig {
    private static Logger log = LoggerFactory.getLogger(DatasourceConfig.class);
    @Value("${druid.driver}")
    private String driverClassName;
    @Value("${druid.url}")
    private String url;
    @Value("${druid.username}")
    private String username;
    @Value("${druid.password}")
    private String password;
    @Value("${druid.init-size}")
    private int initSize;
    @Value("${druid.min-idel}")
    private int minIdel;
    @Value("${druid.max-active}")
    private int maxActive;
    @Value("${druid.login.timeout.seconds}")
    private int loginTimeoutSeconds;
    @Value("${druid.query.timeout.seconds}")
    private int queryTimeoutSeconds;

    @Bean
    public DataSource dataSource() {
        DruidDataSource ds = new DruidDataSource();
        ds.setDriverClassName(driverClassName);
        ds.setUrl(url);
        ds.setUsername(username);
        ds.setPassword(password);
        ds.setInitialSize(initSize);
        ds.setMinIdle(minIdel);
        ds.setMaxActive(maxActive);
        ds.setLoginTimeout(loginTimeoutSeconds);
        ds.setQueryTimeout(queryTimeoutSeconds);
        return ds;
    }

    @Bean
    public SqlSessionFactory sqlSessionFactory() throws Exception {
        final SqlSessionFactoryBean sqlSessionFactory = new SqlSessionFactoryBean();
        sqlSessionFactory.setDataSource(dataSource());
        sqlSessionFactory.setConfigLocation(new ClassPathResource("mybatis-config.xml"));
        sqlSessionFactory.setFailFast(true);
        return sqlSessionFactory.getObject();
    }

    public DataSourceTransactionManager dataSourceTransactionManager() {
        log.debug("> transactionManager");
        return new DataSourceTransactionManager(dataSource());
    }
}

下面写一个实体类

这里我们用到了mysql数据库的系统表来做测试

HelpCategory.java

package com.yundian.entity;
public class HelpCategory {
    private Short helpCategoryId;
    private String name;
    private Short parentCategoryId;
    private String url;
    // getter settter 方法省略了
}

HelpCategoryMapper.java

package com.yundian.mapper;
import com.yundian.entity.HelpCategory;
import org.springframework.stereotype.Repository;
import java.util.List;

@Repository
public interface HelpCategoryMapper {
    List selectList();
}

HelpCategoryService.java

package com.yundian.service;
import com.yundian.entity.HelpCategory;
import java.util.List;
public interface HelpCategoryService {
    List selectList();
}

HelpCategoryServiceImpl.java

package com.yundian.service.impl;
import com.yundian.entity.HelpCategory;
import com.yundian.mapper.HelpCategoryMapper;
import com.yundian.service.HelpCategoryService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.List;
@Service
public class HelpCategoryServiceImpl implements HelpCategoryService {
    @Autowired
    private HelpCategoryMapper helpCategoryMapper;
    @Override
    public List selectList() {
        return helpCategoryMapper.selectList();
    }
}

HelpCategoryController.java

package com.yundian.controller;
import com.yundian.common.Result;
import com.yundian.entity.HelpCategory;
import com.yundian.enums.Code;
import com.yundian.service.HelpCategoryService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
import java.util.List;

@RestController
@RequestMapping("help")
public class HelpCategoryController {
    @Autowired
    private HelpCategoryService helpCategoryService;

    @RequestMapping(value = "category", method = RequestMethod.GET, produces = "application/json;charset=UTF-8")
    public Result category() {
        List list = helpCategoryService.selectList();
        return new Result<>(Code.SUCCESS, list);
    }
}

其他的两个公共类
Result.java

package com.yundian.common;
import com.yundian.enums.Code;
public class Result {
    private int code;
    private String message;
    private T result;
    public Result(Code code, T result) {
        this.code = code.getCode();
        this.message = code.getDesc();
        this.result = result;
    }
    // 省略了get set方法
}

Code.java

package com.yundian.enums;

public enum Code {
    SUCCESS(100, "SUCCESS"), FAIL(101, "FAILED"), unknown(-1, "未知");
    private int code;
    private String desc;

    Code(int code, String desc) {
        this.code = code;
        this.desc = desc;
    }
    public int getCode() {
        return code;
    }
    public String getDesc() {
        return desc;
    }
}

到这里所有的类都编写完了，好了见证奇迹的时候到了
你的运行结果对了吗？

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