### 歡迎訪問我的GitHub
> 這裡分類和彙總了欣宸的全部原創(含配套原始碼)：[https://github.com/zq2599/blog_demos](https://github.com/zq2599/blog_demos)

### 關於Jib
- Java應用如果要執行在docker環境，就要製作包含該應用的docker映象，Jib就是用來製作此映象的的工具，有三種使用Jib的方法：
1. Maven外掛：jib-maven-plugin；
2. Gradle外掛：jib-gradle-plugin；
3. Java庫：Jib Core；

- Jib的官網地址是：https://github.com/GoogleContainerTools/jib

- 今天我們們要聊的是第一種：透過jib的maven外掛將java應用構建成docker映象；
### 實戰環境資訊
1. 作業系統：CentOS Linux release 7.6.1810
2. docker：1.13.1
3. jdk：1.8.0_191
4. maven：3.6.0

- 接下來一起開發一個java應用，並使用jib的maven外掛，來構建該應用對應的docker映象；
### 原始碼下載
- 如果您不打算寫程式碼，也可以從GitHub上下載本次實戰的原始碼，地址和連結資訊如下表所示：

| 名稱      |   連結 |   備註|
| :-------- | :----| :----|
| 專案主頁| https://github.com/zq2599/blog_demos | 該專案在GitHub上的主頁 |
| git倉庫地址(https)| https://github.com/zq2599/blog_demos.git | 該專案原始碼的倉庫地址，https協議 |
| git倉庫地址(ssh)| git@github.com:zq2599/blog_demos.git | 該專案原始碼的倉庫地址，ssh協議 |

- 這個git專案中有多個資料夾，本章的原始碼在hellojib資料夾下，如下圖紅框所示：
![在這裡插入圖片描述](https://img-blog.csdnimg.cn/20190630222504867.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly94aW5jaGVuLmJsb2cuY3Nkbi5uZXQ=,size_16,color_FFFFFF,t_70)

###  準備java應用
- 準備一個最簡單的springboot應用hellojib，用於實戰構建docker映象；
- 該應用是基於maven構建的，啟動類如下：

```java
package com.bolingcavalry.hellojib;

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

@SpringBootApplication
public class HellojibApplication {

public static void main(String[] args) {
        SpringApplication.run(HellojibApplication.class, args);
    }

}
```

- 有一個controller用於後面驗證服務是否正常：

```java
package com.bolingcavalry.hellojib.controller;

import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.text.SimpleDateFormat;
import java.util.Date;

/**
 * @Description: 普通的controller
 * @author: willzhao E-mail: zq2599@gmail.com
 * @date: 2019/6/29 20:21
 */
@RestController
public class HelloController {

@RequestMapping("/hello")
    public String hello(){
        return "Hello, " + new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date());
    }
}
```

-  **最重要的部分來了** ，pom.xml的內容如下，請注意註釋：

```xml
<?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>
    <parent>
        <groupid>org.springframework.boot</groupid>
        <artifactid>spring-boot-starter-parent</artifactid>
        <version>2.1.6.RELEASE</version>
        <relativepath></relativepath> 
    </parent>
    <groupid>com.bolingcavalry</groupid>
    <artifactid>hellojib</artifactid>
    <version>0.0.1-SNAPSHOT</version>
    <name>hellojib</name>
    <description>Demo project for Spring Boot</description>

<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>

<plugin>
                <groupid>com.google.cloud.tools</groupid>
                <artifactid>jib-maven-plugin</artifactid>
                <version>1.3.0</version>
                <configuration>
                    
                    <from>
                        
                        <image>openjdk:8-jdk-stretch</image>
                    </from>
                    <to>
                        
                        <image>bolingcavalry/hellojib:${project.version}</image>
                    </to>
                    
                    <container>
                        
                        <jvmflags>
                            <jvmflag>-Xms4g</jvmflag>
                            <jvmflag>-Xmx4g</jvmflag>
                        </jvmflags>
                        
                        <ports>
                            <port>8080</port>
                        </ports>
                    </container>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>
```

- 上述xml中有以下幾處需要注意：
a. 外掛的節點中增加了外掛jib-maven-plugin的配置；
b. from節點用來設定基礎映象，一般使用openjdk官方映象，如果您想了解更多請參考[《openjdk映象的tag說明》](https://blog.csdn.net/boling_cavalry/article/details/94320638)；
c. to節點用於指定映象名稱和tag；
d. container節點用來設定容器的屬性，例如對外暴露的埠、jvm引數等；

- 完成了上述設定，就可以構建映象了；

### 構建成tar檔案
- 還記得常用的docker到處到處命令麼：
-  **docker save** 命令將本地倉庫的docker映象匯出成tar格式的檔案；
-  **docker load** 命令可以將tar格式的映象檔案匯入到本地映象倉庫；

- 利用Jib，我們可以將java應用做成docker映象並生成tar格式的檔案，操作步驟如下：
- 在上述java工程的pom.xml檔案所在目錄，執行以下命令：

```shell
mvn compile jib:buildTar
```

- 構建成功後，控制檯提示以下資訊：

```shell
[root@centos7 hellojib]# mvn compile jib:buildTar
[INFO] Scanning for projects...
[INFO]
[INFO] ---------------------< com.bolingcavalry:hellojib >---------------------
[INFO] Building hellojib 0.0.1-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-resources-plugin:3.1.0:resources (default-resources) @ hellojib ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 1 resource
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ hellojib ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- jib-maven-plugin:1.3.0:buildTar (default-cli) @ hellojib ---
[INFO]
[INFO] Containerizing application to file at '/root/temp/201906/29/hellojib/target/jib-image.tar'...
[INFO] The base image requires auth. Trying again for openjdk:8-jdk-stretch...
[INFO]
[INFO] Container entrypoint set to [java, -Xms4g, -Xmx4g, -cp, /app/resources:/app/classes:/app/libs/*, com.bolingcavalry.hellojib.HellojibApplication]
[INFO]
[INFO] Built image tarball at /root/temp/201906/29/hellojib/target/jib-image.tar
[INFO] Executing tasks:
[INFO] [==============================] 100.0% complete
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  16.521 s
[INFO] Finished at: 2019-06-30T21:43:32+08:00
[INFO] ------------------------------------------------------------------------
```

- 去java工程的target目錄下，發現生成了名為jib-image.tar的檔案，如下圖紅框所示：
![在這裡插入圖片描述](https://img-blog.csdnimg.cn/20190630214657395.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly94aW5jaGVuLmJsb2cuY3Nkbi5uZXQ=,size_16,color_FFFFFF,t_70)

- 在java工程的target目錄下執行命令 **docker load < jib-image.tar** 即可將該tar檔案中的映象載入到本地映象倉庫：

```shell
[root@centos7 target]# docker load < jib-image.tar
2c8d31157b81: Loading layer [==================================================>] 50.07 MB/50.07 MB
ea20c4bf3aae: Loading layer [==================================================>] 4.932 MB/4.932 MB
51774d97c868: Loading layer [==================================================>]    221 B/221 B
51566e3f832b: Loading layer [==================================================>]   104 MB/104 MB
64c0b8425948: Loading layer [==================================================>] 14.91 MB/14.91 MB
e4c3b920750d: Loading layer [==================================================>]    240 B/240 B
8917d4e7f7b3: Loading layer [==================================================>] 1.034 kB/1.034 kB
Loaded image: bolingcavalry/hellojib:0.0.1-SNAPSHOT
```

- 執行命令 **docker images** 可見映象載入成功：

```shell
[root@centos7 target]# docker images
REPOSITORY                         TAG                         IMAGE ID            CREATED             SIZE
bolingcavalry/hellojib             0.0.1-SNAPSHOT              cf93bd81fbd5        49 years ago        505 MB
```

- 可見透過jib生成的tar是正常的docker映象檔案，可以匯入

### 驗證映象是否可用
- 執行以下命令，即可啟動容器：

```shell
docker run --rm -p 8080:8080 bolingcavalry/hellojib:0.0.1-SNAPSHOT
```

- 控制檯顯示springboot的啟動資訊：

```shell
[root@centos7 target]# docker run --rm -p 8080:8080 bolingcavalry/hellojib:0.0.1-SNAPSHOT

.   ____          _            __ _ _
 /\\ / ___'_ __ _ _(_)_ __  __ _ \ \ \ \
( ( )\___ | '_ | '_| | '_ \/ _` | \ \ \ \
 \\/  ___)| |_)| | | | | || (_| |  ) ) ) )
  '  |____| .__|_| |_|_| |_\__, | / / / /
 =========|_|==============|___/=/_/_/_/
 :: Spring Boot ::        (v2.1.6.RELEASE)

2019-06-30 13:56:50.969  INFO 1 --- [           main] c.b.hellojib.HellojibApplication         : Starting HellojibApplication on c08711533071 with PID 1 (/app/classes started by root in /)
2019-06-30 13:56:50.975  INFO 1 --- [           main] c.b.hellojib.HellojibApplication         : No active profile set, falling back to default profiles: default
2019-06-30 13:56:52.147  INFO 1 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat initialized with port(s): 8080 (http)
2019-06-30 13:56:52.173  INFO 1 --- [           main] o.apache.catalina.core.StandardService   : Starting service [Tomcat]
2019-06-30 13:56:52.173  INFO 1 --- [           main] org.apache.catalina.core.StandardEngine  : Starting Servlet engine: [Apache Tomcat/9.0.21]
2019-06-30 13:56:52.261  INFO 1 --- [           main] o.a.c.c.C.[Tomcat].[localhost].[/]       : Initializing Spring embedded WebApplicationContext
2019-06-30 13:56:52.261  INFO 1 --- [           main] o.s.web.context.ContextLoader            : Root WebApplicationContext: initialization completed in 1223 ms
2019-06-30 13:56:52.475  INFO 1 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Initializing ExecutorService 'applicationTaskExecutor'
2019-06-30 13:56:52.772  INFO 1 --- [           main] o.s.b.w.embedded.tomcat.TomcatWebServer  : Tomcat started on port(s): 8080 (http) with context path ''
2019-06-30 13:56:52.811  INFO 1 --- [           main] c.b.hellojib.HellojibApplication         : Started HellojibApplication in 2.202 seconds (JVM running for 2.446)
```

- 用瀏覽器訪問：http://192.168.121.132:8080/hello ，其中 **192.168.121.132** 是宿主機IP地址，如下圖，可見springboot服務可以正常訪問：
![在這裡插入圖片描述](https://img-blog.csdnimg.cn/20190630220057359.jpg)

### 構建到本地映象倉庫
- 上面的操作是將java應用生成tar檔案然後再匯入到本地映象倉庫，您也可以直接將java應用構建到本地映象倉庫中：
- 先執行命令 **docker rmi bolingcavalry/hellojib:0.0.1-SNAPSHOT** 將前面構建的映象刪除；
- 在pom.xml檔案所在目錄執行以下命令即可：

```shell
mvn clean compile jib:dockerBuild -U
```

- 終端提示如下：

```shell
[root@centos7 hellojib]# mvn clean compile jib:dockerBuild -U
[INFO] Scanning for projects...
[INFO]
[INFO] ---------------------< com.bolingcavalry:hellojib >---------------------
[INFO] Building hellojib 0.0.1-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-clean-plugin:3.1.0:clean (default-clean) @ hellojib ---
[INFO] Deleting /root/temp/201906/29/hellojib/target
[INFO]
[INFO] --- maven-resources-plugin:3.1.0:resources (default-resources) @ hellojib ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 1 resource
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ hellojib ---
[INFO] Changes detected - recompiling the module!
[INFO] Compiling 2 source files to /root/temp/201906/29/hellojib/target/classes
[INFO]
[INFO] --- jib-maven-plugin:1.3.0:dockerBuild (default-cli) @ hellojib ---
[INFO]
[INFO] Containerizing application to Docker daemon as bolingcavalry/hellojib:0.0.1-SNAPSHOT...
[INFO] The base image requires auth. Trying again for openjdk:8-jdk-stretch...
[INFO]
[INFO] Container entrypoint set to [java, -Xms4g, -Xmx4g, -cp, /app/resources:/app/classes:/app/libs/*, com.bolingcavalry.hellojib.HellojibApplication]
[INFO]
[INFO] Built image to Docker daemon as bolingcavalry/hellojib:0.0.1-SNAPSHOT
[INFO] Executing tasks:
[INFO] [==============================] 100.0% complete
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  20.923 s
[INFO] Finished at: 2019-06-30T22:04:36+08:00
[INFO] ------------------------------------------------------------------------
```

- 執行命令 **docker images** 可見映象已經在映象倉庫中了：

```shell
[root@centos7 hellojib]# docker images
REPOSITORY                         TAG                         IMAGE ID            CREATED             SIZE
bolingcavalry/hellojib             0.0.1-SNAPSHOT              cf93bd81fbd5        49 years ago        505 MB
```

### 構建到hub.docker.com

- docker的中央倉庫是 hub.docker.com ，jib也可以在映象構建成功後自動推送到hub.docker.com網站，前提是您已經在該網站註冊過，例如我已經註冊過，賬號是 **bolingcavalry** ，因此名為 **bolingcavalry/XXXXXXXX** 的映象都可以推送到 hub.docker.com：

- 在pom.xml檔案所在目錄執行以下命令即可自動推送到 hub.docker.com，其中bolingcavalry是我在hub.docker.com上的註冊賬號，123456是密碼：

```shell
mvn compile jib:build -Djib.to.auth.username=bolingcavalry -Djib.to.auth.password=123456
```

- 終端資訊如下：

```shell
[root@centos7 hellojib]# mvn compile jib:build -Djib.to.auth.username=bolingcavalry -Djib.to.auth.password=123456
[INFO] Scanning for projects...
[INFO]
[INFO] ---------------------< com.bolingcavalry:hellojib >---------------------
[INFO] Building hellojib 0.0.1-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-resources-plugin:3.1.0:resources (default-resources) @ hellojib ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 1 resource
[INFO] Copying 0 resource
[INFO]
[INFO] --- maven-compiler-plugin:3.8.1:compile (default-compile) @ hellojib ---
[INFO] Nothing to compile - all classes are up to date
[INFO]
[INFO] --- jib-maven-plugin:1.3.0:build (default-cli) @ hellojib ---
[INFO]
[INFO] Containerizing application to bolingcavalry/hellojib:0.0.1-SNAPSHOT...
[INFO] The base image requires auth. Trying again for openjdk:8-jdk-stretch...
[INFO]
[INFO] Container entrypoint set to [java, -Xms4g, -Xmx4g, -cp, /app/resources:/app/classes:/app/libs/*, com.bolingcavalry.hellojib.HellojibApplication]
[INFO]
[INFO] Built and pushed image as bolingcavalry/hellojib:0.0.1-SNAPSHOT
[INFO] Executing tasks:
[INFO] [==============================] 100.0% complete
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  02:47 min
[INFO] Finished at: 2019-06-30T22:16:19+08:00
[INFO] ------------------------------------------------------------------------
```

- 在hub.docker.com上已經可以看到此映象了，如下圖（要登入後再看自己的映象列表，如果沒有登入是無法立即查到的）：
![在這裡插入圖片描述](https://img-blog.csdnimg.cn/20190630222003438.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly94aW5jaGVuLmJsb2cuY3Nkbi5uZXQ=,size_16,color_FFFFFF,t_70)

- 至此，Jib的實戰已經完成，常用的操作相信您已經熟悉了，希望本文能幫助您做出滿意的映象；

### 歡迎關注ITpub：程式設計師欣宸
> [學習路上，你不孤單，欣宸原創一路相伴...](http://blog.itpub.net/70017844/)

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