1.SpringBoot 持久化支持(MyBatis)
- 1.1 XML版本
  - 1.1.1 步骤分析
  - 1.1.2 实现
- 1.2 注解版
2. SpringBoot启动分析
- 2.1 创建SpringApplication对象
- 2.2 运行run方法

1.SpringBoot 持久化支持(MyBatis)

1.1 XML版本

1.1.1 步骤分析

新建maven project;
在pom.xml中引入相关依赖
- （1）基本依赖，jdk版本号；
- （2）mysql驱动，mybatis依赖包，mysql分页PageHelper:
创建启动类App.java
在application.properties添加配置文件；
创建数据库和表
编写domain的测试类User;
编写UserMapper；
编写mybatis的xml文件
编写IUserService接口和接口的实现类UserServiceImpl
编写UserController
编写测试方法，测试service层
启动项目，测试controller层
配置事务。注解式事务
测试事务
获取自增的主键id
使用插件PageHelper分页

1.1.2 实现

新建maven project;
在pom.xml中引入相关依赖
- （1）基本依赖，jdk版本号
- （2）mysql驱动，mybatis依赖包，mysql分页PageHelper


        
            org.springframework.boot
            spring-boot-starter-web
        
        
            org.springframework.boot
            spring-boot-starter-test
        

        
            mysql
            mysql-connector-java
        

        
            org.springframework.boot
            spring-boot-starter-jdbc
        
        
        
            org.mybatis.spring.boot
            mybatis-spring-boot-starter
            1.1.1
        
        
        
            com.github.pagehelper
            pagehelper
            4.1.0

创建启动类App.java

package cn.wangningbo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
@MapperScan("cn.wangningbo.mapper")//注意这个注解，使用mybatis扫描包的mapper包
public class App {
    public static void main(String[] args) {
        SpringApplication.run(App.class, args);
    }
}

在resources下创建配置文件application.yml

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/test
    driver-class-name: com.mysql.jdbc.Driver
    username: root
    password: apy06942
mybatis:
  type-aliases-package: cn.wangningbo.domain,cn.wangningbo.query

创建数据库和表
编写domain的测试类User;

package cn.wangningbo.domain;

public class User {
    private Long id;
    private String name;
    //提供get方法、set方法、无参构造方法和一个name参数的构造方法、toString方法
}

编写UserMapper；

package cn.wangningbo.mapper;

import cn.wangningbo.domain.User;

import java.util.List;

public interface UserMapper {
    void save(User user);

    List loadAll();
}

编写mybatis的xml文件

在resources下创建目录cn/wangningbo/mapper,在此目录下创建相应的映射xml,UserMapper.xml





    
        INSERT into t_user (name) values (#{name})

编写IUserService接口和接口的实现类UserServiceImpl

package cn.wangningbo.service;

import cn.wangningbo.domain.User;

import java.util.List;

public interface IUserService {
    void add(User user);

    List getAll();
}

package cn.wangningbo.service.impl;

import cn.wangningbo.domain.User;
import cn.wangningbo.mapper.UserMapper;
import cn.wangningbo.service.IUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

@Service
public class UserServiceImpl implements IUserService {
    @Autowired
    private UserMapper userMapper;

    public void add(User user) {
        userMapper.save(user);
    }

    public List getAll() {
        return userMapper.loadAll();
    }
}

编写UserController

package cn.wangningbo.controller;

import cn.wangningbo.domain.User;
import cn.wangningbo.service.IUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.List;

@RestController
@RequestMapping("/user")
public class UserController {
    @Autowired
    private IUserService userService;

    //保存由测试做就行，这里就不写页面了
    //查询所有
    @GetMapping
    public List getAll() {
        return userService.getAll();
    }
}

编写测试方法，测试service层

package cn.wangningbo.service;

import cn.wangningbo.App;
import cn.wangningbo.domain.User;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.test.context.junit4.SpringRunner;

import java.util.List;

@RunWith(SpringRunner.class)
@SpringBootTest(classes = App.class)
public class IUserServiceTest {
    @Autowired
    private IUserService userService;

    @Test
    public void add() {
        userService.add(new User("二狗"));
        userService.add(new User("张三"));
    }

    @Test
    public void getAll() {
        List list = userService.getAll();
        for (User user : list) {
            System.out.println(user);
        }
    }
}

启动项目，测试controller层

http://localhost:8080/user

配置事务。注解式事务

在service层加入事务

//类级别值只读事务
@Transactional(propagation = Propagation.SUPPORTS,readOnly = true)

//在类里面写方法上面打写事务,下面这两种的效果是一样的
//@Transactional(propagation = Propagation.REQUIRED,readOnly = false)
@Transactional

package cn.wangningbo.service.impl;

import cn.wangningbo.domain.User;
import cn.wangningbo.mapper.UserMapper;
import cn.wangningbo.service.IUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;

import java.util.List;

//类级别值只读,在类里面写方法上面打写事务
@Service
@Transactional(propagation = Propagation.SUPPORTS, readOnly = true)
public class UserServiceImpl implements IUserService {
    @Autowired
    private UserMapper userMapper;

    //@Transactional(propagation = Propagation.REQUIRED,readOnly = false)
    @Transactional
    public void add(User user) {
        userMapper.save(user);
        // int i = 1/0;
    }

    public List getAll() {
        return userMapper.loadAll();
    }
}

测试事务

由于在service那里的add方法弄了一个int i = 1/0;事务成功了就不会添加到数据库，注释掉那一行 int i = 1/0;就会添加到数据库。

获取自增的主键id

只需要在Mapper.xml里面的添加方法配置一下useGeneratedKeys="true" keyProperty="id" keyColumn="id"

UserMapper.xml




    
        INSERT into t_user (name) values (#{name})

测试是否获得主键id,执行测试方法输出查看是否有id

    @Test
    public void add() {
        User user = new User("二狗");
        System.out.println(user.getId());
        userService.add(user);
        System.out.println(user.getId());
    }

输出结果:
null
6

使用插件PageHelper分页

PageHelper是mybatis一个插件,可以用它完成分页

步骤：导入jaar，在配置类里面配置Bean，测试

导入jar

        
            com.github.pagehelper
            pagehelper
            4.1.0

配置

package cn.wangningbo.config;

import com.github.pagehelper.PageHelper;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import java.util.Properties;

@Configuration
public class MyConfig {
    @Bean
    public PageHelper pageHelper() {
        System.out.println("MyBatisConfiguration.pageHelper()");
        PageHelper pageHelper = new PageHelper();
        Properties p = new Properties();
        p.setProperty("offsetAsPageNum", "true");
        p.setProperty("rowBoundsWithCount", "true");
        p.setProperty("reasonable", "true");
        pageHelper.setProperties(p);
        return pageHelper;
    }
}

service层进行分页

    public List getAll() {
        PageHelper.startPage(1, 3);
        return userMapper.loadAll();
    }

测试

@Test
    public void getAll() {
        //此时list已经不是传统list,相当于原来pageList
        Page list = (Page) userService.getAll();
        //class com.github.pagehelper.Page
        System.out.println(list.getClass());

        //还有分页信息
        System.out.println(list.getTotal());
        System.out.println(list.getPageNum());

        //获取数据:本身也是一个继承与ArraList的List
        for (User user : userService.getAll()) {
            System.out.println(user);
        }
    }

输出结果

class com.github.pagehelper.Page
5
1
User{id=1, name='二狗'}
User{id=2, name='张三'}
User{id=4, name='二狗'}

1.2 注解版

注解版与xml版很相似，我只简单说几句不一样的地方

注解版使用mybatis的时候，只需要在Mapper接口那里的方法头上打注解即可，以前使用xml版本的时候都是在xml里面写的查询，添加等方法！

package cn.wangningbo.mapper;

import cn.wangningbo.domain.User;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Options;
import org.apache.ibatis.annotations.Select;

import java.util.List;

public interface UserMapper {
    @Options(useGeneratedKeys = true, keyProperty = "id", keyColumn = "id")
    @Insert("insert into t_user(name) values (#{name})")
    void save(User user);

    @Select("select * from t_user")
    List loadAll();
}

2. SpringBoot启动分析

2.1 创建SpringApplication对象

initialize(sources);
private void initialize(Object[] sources) {
    //保存主配置类
    if (sources != null && sources.length > 0) {
        this.sources.addAll(Arrays.asList(sources));
    }
    //判断当前是否一个web应用
    this.webEnvironment = deduceWebEnvironment();
    //从类路径下找到META-INF/spring.factories配置的所有ApplicationContextInitializer；然后保存起来
    setInitializers((Collection) getSpringFactoriesInstances(
        ApplicationContextInitializer.class));
    //从类路径下找到ETA-INF/spring.factories配置的所有ApplicationListener
    setListeners((Collection) getSpringFactoriesInstances(ApplicationListener.class));
    //从多个配置类中找到有main方法的主配置类
    this.mainApplicationClass = deduceMainApplicationClass();
}

2.2 运行run方法

public ConfigurableApplicationContext run(String... args) {
   StopWatch stopWatch = new StopWatch();
   stopWatch.start();
   ConfigurableApplicationContext context = null;
   FailureAnalyzers analyzers = null;
   configureHeadlessProperty();
    
   //获取SpringApplicationRunListeners；从类路径下META-INF/spring.factories
   SpringApplicationRunListeners listeners = getRunListeners(args);
    //回调所有的获取SpringApplicationRunListener.starting()方法
   listeners.starting();
   try {
       //封装命令行参数
      ApplicationArguments applicationArguments = new DefaultApplicationArguments(
            args);
      //准备环境
      ConfigurableEnvironment environment = prepareEnvironment(listeners,
            applicationArguments);
            //创建环境完成后回调SpringApplicationRunListener.environmentPrepared()；表示环境准备完成
       
      Banner printedBanner = printBanner(environment);
       
       //创建ApplicationContext；决定创建web的ioc还是普通的ioc
      context = createApplicationContext();
       
      analyzers = new FailureAnalyzers(context);
       //准备上下文环境;将environment保存到ioc中；而且applyInitializers()；
       //applyInitializers()：回调之前保存的所有的ApplicationContextInitializer的initialize方法
       //回调所有的SpringApplicationRunListener的contextPrepared()；
       //
      prepareContext(context, environment, listeners, applicationArguments,
            printedBanner);
       //prepareContext运行完成以后回调所有的SpringApplicationRunListener的contextLoaded（）；
       
       //刷新容器；ioc容器初始化（如果是web应用还会创建嵌入式的Tomcat）；Spring注解版
       //扫描，创建，加载所有组件的地方；（配置类，组件，自动配置）
      refreshContext(context);
       //从ioc容器中获取所有的ApplicationRunner和CommandLineRunner进行回调
       //ApplicationRunner先回调，CommandLineRunner再回调
      afterRefresh(context, applicationArguments);
       //所有的SpringApplicationRunListener回调finished方法
      listeners.finished(context, null);
      stopWatch.stop();
      if (this.logStartupInfo) {
         new StartupInfoLogger(this.mainApplicationClass)
               .logStarted(getApplicationLog(), stopWatch);
      }
       //整个SpringBoot应用启动完成以后返回启动的ioc容器；
      return context;
   }
   catch (Throwable ex) {
      handleRunFailure(context, listeners, analyzers, ex);
      throw new IllegalStateException(ex);
   }
}

SpringBoot-day3