2018-8-2关于spring和springboot的初步学习

学习笔记,spring,springboot,maven

今天因为偶然的情况学习起了 springboot了解了一些不同

区别:

  1. 内部集成了tomcat
  2. maven文件pom简化
  3. 解决了依赖等的自行配置
  4. 热部署

阅读了http://tengj.top/2017/02/26/springboot1/#Spring-Boot%E7%B2%BE%E8%A6%81 大佬的博客后了解到

关于maven文件pom的简化:

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<?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>MySpringHelllo</groupId>
    <artifactId>MySringTest</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>LATEST</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.11</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>LATEST</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>5.1.0.BUILD-SNAPSHOT</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-tx</artifactId>
            <version>4.3.18.RELEASE</version>
            <!--<version>LATEST</version>-->
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-webmvc</artifactId>
            <version>5.1.0.BUILD-SNAPSHOT</version>
        </dependency>
        <dependency>
            <groupId>javax.servlet</groupId>
            <artifactId>javax.servlet-api</artifactId>
            <version>4.0.1</version>
        </dependency>
    </dependencies>
</project>

上面就是基于mysql和springmvc的最简单的数据库添加的例子

如下是springboot的pom页面例子

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<?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.orochi</groupId>
    <artifactId>helloworld</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>helloworld</name>
    <description>Demo project for Spring Boot</description>

    <!--这是父级依赖目的是简化查找version的操作该功能主要是通过本地的maven的.m2文件里的设置实现的-->
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.4.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>1.8</java.version>
    </properties>

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

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>

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


</project>

可以不难看到导入的pom全部都简化了这个标签
具体实现原因是因为导入了

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<parent>
     <groupId>org.springframework.boot</groupId>
     <artifactId>spring-boot-starter-parent</artifactId>
     <version>2.0.4.RELEASE</version>
     <relativePath/> <!-- lookup parent from repository -->
 </parent>

这个标签之后除了自定义的java版本那一项其余的均没有使用version了
这个配置名为父级依赖 作用就是在导入后常用的大多数包都会免去version的标签
类似与本地cdn有木有o.o 具体包的maven默认依赖可以在.m2目录下的

.m2\repository\org\springframework\boot\spring-boot-dependencies\2.0.4.RELEASE

这个目录下查看到

此文还没写完持续更新溜ε=ε=ε=┏(゜ロ゜;)┛

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@SpringBootApplication

这个注解的作用是开启自动配置是SpringBoot的核心注解

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@RestController
@ResponseBody
@Controller

这三个注解的作用是注解类里面的方法都以json格式输出
RestController = ResponseBody + Controller

启动SpringBoot的三种方法

  1. main方法启动
  2. 使用命令

    mvn spring-boot:run启动

3.运行mvn package打包 然后 java- jar启动