springboot整合mybatis xml方式配置SQL

springboot免去了一大堆的xml配置，达到了开箱即用，springboot中的springdatajpa是完整的ORM框架，对于简单的字段可以直接通过方法中的字段名即可，但是对于有些情况下，复杂的查询，查询的调优还是用mybatis这种半自动的框架比较合适，mybatis也可以注解开发，但是为了更加流程的开发体验还是用xml噢诶值的方式更加让人喜欢

整合步骤

1. 引入依赖

可以使用IDEA方便的选择主要的start

<?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.marry.dezhou</groupId>
    <artifactId>fg</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>fg</name>
    <description></description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.4.7.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <java.version>1.7</java.version>
        <commons-lang3.version>3.4</commons-lang3.version>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>1.3.1</version>
        </dependency>

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

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
        <!--引入druid的maven-->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid</artifactId>
            <version>1.0.29</version>
        </dependency>

        <!-- 阿里巴巴fastjson，解析json视图 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.15</version>
        </dependency>
        <!--oracle数据库-->
        <dependency>
            <groupId>ojdbc</groupId>
            <artifactId>ojdbc14</artifactId>
            <version>10.2.0.4.0</version>
        </dependency>

        <dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>${commons-lang3.version}</version>
        </dependency>

    </dependencies>

    <build>
        <finalName>fgshare</finalName>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>


</project>

推荐使用阿里的Druid数据库连接池，监控功能可以方便得查看每个SQL的执行时间等信息，对于调优很方便

2.配置数据库连接

这里使用的.yml格式的配置文件

spring:
  datasource:
    type: com.alibaba.druid.pool.DruidDataSource
    driver-class-name: oracle.jdbc.driver.OracleDriver
    url: jdbc:oracle:thin:@127.0.0.1:1521:orcl
    username: estate_dz
    password: estate
    #最大活跃数
    maxActive: 50
    #初始化数量
    initialSize: 1
    #最大连接等待超时时间
    maxWait: 60000
    #打开PSCache，并且指定每个连接PSCache的大小
    poolPreparedStatements: true
    maxPoolPreparedStatementPerConnectionSize: 20
    #通过connectionProperties属性来打开mergeSql功能；慢SQL记录
    #connectionProperties: druid.stat.mergeSql=true;druid.stat.slowSqlMillis=5000
    minIdle: 1
    timeBetweenEvictionRunsMillis: 60000
    minEvictableIdleTimeMillis: 300000
    validationQuery: select 1 from dual
    testWhileIdle: true
    testOnBorrow: false
    testOnReturn: false
    #配置监控统计拦截的filters，去掉后监控界面sql将无法统计,'wall'用于防火墙
    filters: stat, log4j

为了可以正确显示监控等信息，还需要具体配置一下，springboot是java配置的形式

@Configuration
public class DruidConfiguration {

    @Bean(initMethod = "init",destroyMethod = "close")
    @ConfigurationProperties(prefix = "spring.datasource")
    public DruidDataSource dataSource(){
        return new DruidDataSource();
    }

    @Bean
    public ServletRegistrationBean statViewServlet(){

        ServletRegistrationBean servletRegistrationBean=new ServletRegistrationBean(new StatViewServlet(),"/druid/*");
        servletRegistrationBean.addInitParameter("loginUsername","malin");
        servletRegistrationBean.addInitParameter("loginPassword","123456");

        servletRegistrationBean.addInitParameter("resetEnable","false");
        return servletRegistrationBean;
    }

    @Bean
    public FilterRegistrationBean statFilter(){
        FilterRegistrationBean filterRegistrationBean=new FilterRegistrationBean(new WebStatFilter());

        filterRegistrationBean.addUrlPatterns("/*");

        filterRegistrationBean.addInitParameter("exclusions","*.js,*.gif,*.jpg,*.png,*.css,*.ico,/druid/*");
        return filterRegistrationBean;

    }
}

@Bean(initMethod = "init",destroyMethod = "close")initMethod参数不配置的话监控页面的数据源界面可能无法正确显示

3.配置mybatis的配置文件及.xml等

还是application.yml文件添加代码

mybatis:
  mapper-locations: classpath:mapper/*.xml
  type-aliases-package: com.marry.dezhou.fg.domain
  config-location: classpath:mybatis-config.xml

mapper-locations 指定.xml文件所在的位置
type-aliases-package 指定别名的包 写type时直接写类名即可
type-aliases-package 指定mybatis其他配置文件的位置 比如可以在控制台打印sql

4.编写Mapper接口

import com.marry.dezhou.fg.domain.Houseroom;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;

/**
 * Created by ml on 2017-10-26.
 */
@Mapper
public interface StudentMapper {

    /**
     * 通过名字获去学生
     * @param name
     * @return
     */
    Student selectStudentByName(@Param("name") String name);
}
}

直接在相应的接口上写上@Mapper注解即可
方法名即是接下来写在.xml文件中的查询id
@Param()注解将字段映射到.xml文件中的#{}参数中 一个参数的话可以不写

5.编写xml文件

<?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.marry.dezhou.fg.mapper.StudentMapper">

    <select id="selectStudentByName" resultType="Student">
        SELECT *
        FROM STUDENT
        WHERE NAME= #{name}
    </select>

</mapper>

namespace 写上需要连接到的Mapper接口的全类名

6.完工 在需要的地方将接口注入就行了

附上mybatis-config.xml的配置文件

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
    <!-- 设置运行参数 -->
    <settings>
        <!-- 全局映射器启用缓存 -->
        <setting name="cacheEnabled" value="true" />
        <!-- 查询时,关闭关联对象及时加载以提高性能 -->
        <setting name="lazyLoadingEnabled" value="false" />
        <!-- 设置关联对象加载的形态,此处为按需加载字段(加载字段由SQL指定),不会加载关联表的所有字段,以提高性能 -->
        <setting name="aggressiveLazyLoading" value="false" />
        <!-- 对于位置的SQL查询,允许返回不同的结果集以达到通用的效果 -->
        <setting name="multipleResultSetsEnabled" value="true" />
        <!-- 允许使用列标签代替列明 -->
        <setting name="useColumnLabel" value="true" />
        <!-- 允许使用自定义的主键值(比如由程序生成的UUID 32位编码作为键值), 数据表的pk生成策略将被覆盖 -->
        <setting name="useGeneratedKeys" value="true" />
        <!-- 给予被嵌套的resultMap以字段-属性的映射支持 -->
        <setting name="autoMappingBehavior" value="PARTIAL" />
        <!-- 对于批量更新操作缓存SQL以提高性能 -->
        <setting name="defaultExecutorType" value="REUSE" />
        <!-- 数据库超过25000秒仍未响应则超时 -->
        <setting name="defaultStatementTimeout" value="25000" />
        <!-- 打印查询语句 -->
        <!--<setting name="logImpl" value="STDOUT_LOGGING" />-->
        <setting name="logImpl" value="SLF4J"/>
    </settings>
</configuration>