Spring Boot 启动加载数据 CommandLineRunner

实际应用中，我们会有在项目服务启动的时候就去加载一些数据或做一些事情这样的需求。
为了解决这样的问题，Spring Boot 为我们提供了一个方法，通过实现接口 CommandLineRunner 来实现。

很简单，只需要一个类就可以，无需其他配置。
创建实现接口 CommandLineRunner 的类

<span class="hljs-keyword">package org.springboot.sample.runner;

<span class="hljs-keyword">import org.springframework.boot.CommandLineRunner;
<span class="hljs-keyword">import org.springframework.stereotype.Component;

<span class="hljs-javadoc">/**
 * &#x670D;&#x52A1;&#x542F;&#x52A8;&#x6267;&#x884C;
 *
 *<span class="hljs-javadoctag"> @author   &#x5355;&#x7EA2;&#x5B87;(365384722)
 *<span class="hljs-javadoctag"> @myblog  http://blog.csdn.net/catoop/
 *<span class="hljs-javadoctag"> @create    2016&#x5E74;1&#x6708;9&#x65E5;
 */
<span class="hljs-annotation">@Component
<span class="hljs-keyword">public <span class="hljs-class"><span class="hljs-keyword">class <span class="hljs-title">MyStartupRunner1 <span class="hljs-keyword">implements <span class="hljs-title">CommandLineRunner {

    <span class="hljs-annotation">@Override
    <span class="hljs-keyword">public <span class="hljs-keyword">void <span class="hljs-title">run(String... args) <span class="hljs-keyword">throws Exception {
        System.out.println(<span class="hljs-string">">>>>>>>>>>>>>>>&#x670D;&#x52A1;&#x542F;&#x52A8;&#x6267;&#x884C;&#xFF0C;&#x6267;&#x884C;&#x52A0;&#x8F7D;&#x6570;&#x636E;&#x7B49;&#x64CD;&#x4F5C;<<<<<<<<<<<<<"); } }< span></");></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

Spring Boot应用程序在启动后，会遍历CommandLineRunner接口的实例并运行它们的run方法。也可以利用@Order注解（或者实现Order接口）来规定所有CommandLineRunner实例的运行顺序。

如下我们使用@Order 注解来定义执行顺序。

<span class="hljs-keyword">package org.springboot.sample.runner;

<span class="hljs-keyword">import org.springframework.boot.CommandLineRunner;
<span class="hljs-keyword">import org.springframework.core.annotation.Order;
<span class="hljs-keyword">import org.springframework.stereotype.Component;

<span class="hljs-javadoc">/**
 * &#x670D;&#x52A1;&#x542F;&#x52A8;&#x6267;&#x884C;
 *
 *<span class="hljs-javadoctag"> @author   &#x5355;&#x7EA2;&#x5B87;(365384722)
 *<span class="hljs-javadoctag"> @myblog  http://blog.csdn.net/catoop/
 *<span class="hljs-javadoctag"> @create    2016&#x5E74;1&#x6708;9&#x65E5;
 */
<span class="hljs-annotation">@Component
<span class="hljs-annotation">@Order(value=<span class="hljs-number">2)
<span class="hljs-keyword">public <span class="hljs-class"><span class="hljs-keyword">class <span class="hljs-title">MyStartupRunner1 <span class="hljs-keyword">implements <span class="hljs-title">CommandLineRunner {

    <span class="hljs-annotation">@Override
    <span class="hljs-keyword">public <span class="hljs-keyword">void <span class="hljs-title">run(String... args) <span class="hljs-keyword">throws Exception {
        System.out.println(<span class="hljs-string">">>>>>>>>>>>>>>>&#x670D;&#x52A1;&#x542F;&#x52A8;&#x6267;&#x884C;&#xFF0C;&#x6267;&#x884C;&#x52A0;&#x8F7D;&#x6570;&#x636E;&#x7B49;&#x64CD;&#x4F5C; 11111111 <<<<<<<<<<<<<"); } }< span></");></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

<span class="hljs-keyword">package org.springboot.sample.runner;

<span class="hljs-keyword">import org.springframework.boot.CommandLineRunner;
<span class="hljs-keyword">import org.springframework.core.annotation.Order;
<span class="hljs-keyword">import org.springframework.stereotype.Component;

<span class="hljs-javadoc">/**
 * &#x670D;&#x52A1;&#x542F;&#x52A8;&#x6267;&#x884C;
 *
 *<span class="hljs-javadoctag"> @author   &#x5355;&#x7EA2;&#x5B87;(365384722)
 *<span class="hljs-javadoctag"> @myblog  http://blog.csdn.net/catoop/
 *<span class="hljs-javadoctag"> @create    2016&#x5E74;1&#x6708;9&#x65E5;
 */
<span class="hljs-annotation">@Component
<span class="hljs-annotation">@Order(value=<span class="hljs-number">1)
<span class="hljs-keyword">public <span class="hljs-class"><span class="hljs-keyword">class <span class="hljs-title">MyStartupRunner2 <span class="hljs-keyword">implements <span class="hljs-title">CommandLineRunner {

    <span class="hljs-annotation">@Override
    <span class="hljs-keyword">public <span class="hljs-keyword">void <span class="hljs-title">run(String... args) <span class="hljs-keyword">throws Exception {
        System.out.println(<span class="hljs-string">">>>>>>>>>>>>>>>&#x670D;&#x52A1;&#x542F;&#x52A8;&#x6267;&#x884C;&#xFF0C;&#x6267;&#x884C;&#x52A0;&#x8F7D;&#x6570;&#x636E;&#x7B49;&#x64CD;&#x4F5C; 22222222 <<<<<<<<<<<<<"); } }< span></");></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>

启动程序后，控制台输出结果为：

<span class="xml"><span class="hljs-tag">>>>>>>>>>>>>>>>&#x670D;&#x52A1;&#x542F;&#x52A8;&#x6267;&#x884C;&#xFF0C;&#x6267;&#x884C;&#x52A0;&#x8F7D;&#x6570;&#x636E;&#x7B49;&#x64CD;&#x4F5C; 22222222 <span class="hljs-tag"><<<<<<<<<<<<<
>>>>>>>>>>>>>>>&#x670D;&#x52A1;&#x542F;&#x52A8;&#x6267;&#x884C;&#xFF0C;&#x6267;&#x884C;&#x52A0;&#x8F7D;&#x6570;&#x636E;&#x7B49;&#x64CD;&#x4F5C; 11111111 <span class="hljs-tag"><<<<<<<<<<<<<</span></span></span></span>

根据控制台结果可判断，@Order 注解的执行优先级是按value值从小到大顺序。

转自：http://blog.csdn.net/catoop/article/details/50501710

Original: https://www.cnblogs.com/gmq-sh/p/7742118.html
Author: 园芳宝贝
Title: Spring Boot 启动加载数据 CommandLineRunner