Spring Boot + MyBatis + PostgreSql

Maven构建项目

1、访问http://start.spring.io/

2、选择构建工具Maven Project、Spring Boot版本1.3.6以及一些工程基本信息，点击“Switch to the full version.”java版本选择1.7，可参考下图所示：

3、点击Generate Project下载项目压缩包

4、解压后，使用eclipse，Import -> Existing Maven Projects -> Next ->选择解压后的文件夹-> Finsh，OK done!

项目结构介绍

如上图所示，Spring Boot的基础结构共三个文件:

l src/main/java  程序开发以及主程序入口

l src/main/resources 配置文件

l src/test/java  测试程序

另外，spingboot建议的目录结果如下：

root package结构：com.example.myproject

com
  +- example
    +- myproject
      +- Application.java
      |
      +- domain
      |  +- Customer.java
      |  +- CustomerRepository.java
      |
      +- service
      |  +- CustomerService.java
      |
      +- controller
      |  +- CustomerController.java
      |

1、Application.java 建议放到跟目录下面,主要用于做一些框架配置

2、domain目录主要用于实体（Entity）与数据访问层（Repository）

3、service 层主要是业务类代码

4、controller 负责页面访问控制

采用默认配置可以省去很多配置，当然也可以根据自己的喜欢来进行更改

最后，启动Application main方法，至此一个java项目搭建好了！

安装PostgreSql数据库

1、pom.xml中添加支持DB的模块：

        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
        </dependency>

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

        <dependency>
            <groupId>org.postgresql</groupId>
            <artifactId>postgresql</artifactId>
        </dependency>

2、resources/application.properties中加入数据库配置链接

spring.datasource.driver-class-name= org.postgresql.Driver
spring.datasource.url = jdbc:postgresql://localhost:5432/
spring.datasource.username = postgres
spring.datasource.password = 123

3、编写代码

（1）ReleaseFeature.java

 package com.cetc38.cfBlog.bean;

 public class ReleaseFeature {

     private String author;
     private String date;
     private String number;
     private String content;

     public String getAuthor() {
         return author;
     }

     public void setAuthor(String author) {
         this.author = author;
     }

     public String getDate() {
         return date;
     }

     public void setDate(String date) {
         this.date = date;
     }

     public String getNumber() {
         return number;
     }

     public void setNumber(String number) {
         this.number = number;
     }

     public String getContent() {
         return content;
     }

     public void setContent(String content) {
         this.content = content;
     }
 }

（2）ReleaseFeatureService.java

package com.cetc38.cfBlog.service;

import com.cetc38.cfBlog.bean.ReleaseFeature;
import org.apache.ibatis.annotations.Mapper;
import java.util.List;

@Mapper
public interface ReleaseFeatureService {

    public List<ReleaseFeature> findAllReleaseFeature( );

}

（3）添加mapper.xml文件

如上图添加完模板以后，新建mapper文件如下：

（4）ReleaseFeatureMapper.xml

 <?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.cetc38.cfBlog.mapper.ReleaseFeatureMapper">
     <select id="findAll" resultType="com.cetc38.cfBlog.bean.ReleaseFeature">
         select * from release_feature
     </select>
 </mapper>

（5）ReleaseFeatureServiceImpl.java

package com.cetc38.cfBlog.service.impl;

import com.cetc38.cfBlog.bean.ReleaseFeature;
import com.cetc38.cfBlog.mapper.ReleaseFeatureMapper;
import com.cetc38.cfBlog.service.ReleaseFeatureService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class ReleaseFeatureServiceImpl implements ReleaseFeatureService {

    @Autowired
    private ReleaseFeatureMapper releaseFeatureMapper;

    public List<ReleaseFeature> findAllReleaseFeature( ) {
        List<ReleaseFeature> list = releaseFeatureMapper.findAll();
        return  list;
    }

}

（6）ReleaseFeatureController.java

package com.cetc38.cfBlog.controller;

import com.cetc38.cfBlog.bean.ReleaseFeature;
import com.cetc38.cfBlog.service.ReleaseFeatureService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
public class ReleaseFeatureController {

    @Autowired
    private ReleaseFeatureService releaseFeatureService;

    @RequestMapping("list")
    public List<ReleaseFeature> list( ){
        List<ReleaseFeature> list = releaseFeatureService.findAllReleaseFeature();
        return list;
    }

}

4、安装Free MyBatis plugin插件，打开IDEA ， file--> settings-->plugins，在页面中选择browse repositories-->输入mybatis plugin-->选择Free MyBatis plugin来安装：

5、idea项目中添加mapper.xml文件样例，点击File --->Settings --->步骤如下图

6、设置IDEA Proxy

7、解决@Mapper注解不起作用的问题

import org.apache.ibatis.annotations.Mapper;

经导入后，@Mapper注解才可以使用

            <plugin>
                <groupId>org.mybatis.generator</groupId>
                <artifactId>mybatis-generator-maven-plugin</artifactId>
                <version>1.3.7</version>
                <configuration>
                    <verbose>true</verbose>
                    <overwrite>true</overwrite>
                </configuration>
            </plugin>

在maven中配置以上插件配合以下的MyBatis依赖才起作用：

        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.5</version>
        </dependency>

        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>1.3.2</version>
        </dependency>

        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.2</version>
        </dependency>

引入web模块

1、pom.xml中添加支持web的模块：

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

pom.xml文件中默认有两个模块：

spring-boot-starter：核心模块，包括自动配置支持、日志和YAML；

spring-boot-starter-test：测试模块，包括JUnit、Hamcrest、Mockito。

2、编写controller内容

@RestController
public class HelloWorldController {
    @RequestMapping("/hello")
    public String index() {
        return "Hello World";
    }
}

@RestController的意思就是controller里面的方法都以json格式输出，不用再写什么jackjson配置的了！

3、启动主程序，打开浏览器访问http://localhost:8080/hello，就可以看到效果了，有木有很简单！