VS Code开发Java笔记

VSCode开发Java+Spring，参考https://zhuanlan.zhihu.com/p/54358113

前提

1. 确认本机已安装 JAVA SDK
2. 确认本机已安装Maven
3. 确认本机已安装Tomcat

比如我的环境

C:\Program Files\Java\jdk1.8.0_211
C:\Program Files\Java\jre1.8.0_211
D:\Maven\apache-maven-3.6.1
D:\apache-tomcat-9.0.20
win 7, 64bit

安装JDK，JRE

参考https://www.cnblogs.com/liuhongfeng/p/4177568.html

我配置的环境变量
 

JAVA_HOME
CLASSPATH

安装Maven

参考https://www.cnblogs.com/liuhongfeng/p/5057827.html

安装tomcat

参考https://www.cnblogs.com/liuhongfeng/p/4177835.html

环境变量

Tomcat

JDK

Path

需要安装的插件

在 Visual Studio Code 中打开扩展视图(Ctrl+Shift+X)，输入关键词java、spring分别下载Java开发插件包和springboot插件包

VS Code的设置Settings.json

{
    "editor.accessibilitySupport": "off",
    "java.home": "C:/Program Files/Java/jdk1.8.0_211",
    "maven.executable.path":"D:/Maven/apache-maven-3.6.1/bin/mvn.cmd",
    "java.configuration.maven.userSettings":"D:/Maven/apache-maven-3.6.1/conf/settings.xml",
    "maven.terminal.useJavaHome": true,
    "maven.terminal.customEnv": [
        {
            "environmentVariable": "MAVEN_OPTS",               // variable name
            "value": "-Xms1024m -Xmx4096m"                     // value
        },
        {
            "environmentVariable": "JAVA_HOME",                // variable name
            "value": "C:/Program Files/Java/jdk1.8.0_211"      // value
        }
    ],
    "editor.suggestSelection": "first",
    "vsintellicode.modify.editor.suggestSelection": "automaticallyOverrodeDefaultValue"
}

参考：https://marketplace.visualstudio.com/items?itemName=redhat.java

Spring Boot小项目示例

以下项目都是网页输出Hello World级别的项目

参考1：https://blog.csdn.net/smilejiasmile/article/details/89510867

参考2：https://blog.csdn.net/xiaocy66/article/details/82875770

参考3：http://www.kakadanica.com/2018/07/03/%E4%B8%80%E7%AF%87%E6%96%87%E7%AB%A0%E6%90%9E%E5%AE%9A%E5%9C%A8vscode%E4%B8%AD%E8%BF%90%E8%A1%8Cspringboot%E9%A1%B9%E7%9B%AE/

遇到的问题

错误内容

Project build error: Non-resolvable parent POM for com.example:demo:0.0.1-SNAPSHOT: Failure to transfer org.springframework.boot:spring-boot-starter-parent:pom:2.1.5.RELEASE from https://repo.maven.apache.org/maven2 was cached in the local repository, resolution will not be reattempted until the update interval of central has elapsed or updates are forced. Original error: Could not transfer artifact org.springframework.boot:spring-boot-starter-parent:pom:2.1.5.RELEASE from/to central (https://repo.maven.apache.org/maven2): connect timed out and 'parent.relativePath' points at no local POMJava(0)

pom.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>2.1.5.RELEASE</version>
		<relativePath/> <!-- lookup parent from repository -->
	</parent>
	<groupId>com.example</groupId>
	<artifactId>demo</artifactId>
	<version>0.0.1-SNAPSHOT</version>
	<name>demo</name>
	<description>Demo project for Spring Boot</description>

	<properties>
		<java.version>1.8</java.version>
	</properties>

解决

Open your Maven pom.xml file or Gradle build.gradle file, then run VS Code command "Java: Update project configuration" to force the language server to update the project configuration/classpath.

Java:Update Project configuration (Shift+Alt+U): is available when the editor is focused on a Maven pom.xml or a Gradle file. It forces project configuration / classpath updates (eg. dependency changes or Java compilation level), according to the project build descriptor.

参考1：https://github.com/Microsoft/vscode-java-debug/blob/master/Troubleshooting.md#try

参考2：https://marketplace.visualstudio.com/items?itemName=redhat.java

错误内容2

The project 'demo' is not a valid java project.
错误: 找不到或无法加载主类

Maven可能需要proxy

如果在公司内部，通常会需要proxy

D:\Maven\apache-maven-3.6.1\conf\settings.xml

  <proxies>
    <!-- proxy
     | Specification for one proxy, to be used in connecting to the network.
     |
    -->
    <proxy>
      <id>optional</id>
      <active>true</active>
      <protocol>http</protocol>
      <!--
      <username>proxyuser</username>
      <password>proxypass</password>-->
      <host>cn-proxy.jp.oracle.com</host>
      <port>80</port>
      <nonProxyHosts>local.net|some.host.com</nonProxyHosts>
    </proxy>
  </proxies>

参考1：https://github.com/microsoft/vscode-java-debug/blob/master/Troubleshooting.md

参考2：https://blog.csdn.net/x_san3/article/details/82222907

执行Maven编译

鼠标右键，Maven Projects ->demo，选择install

PS D:\Develop\demo> cmd /c "D:\Maven\apache-maven-3.6.1\bin\mvn.cmd" install -f "d:\Develop\demo\pom.xml"
[INFO] Scanning for projects...
[INFO]
[INFO] --------------------------< com.example:demo >--------------------------
[INFO] Building demo 0.0.1-SNAPSHOT
[INFO] --------------------------------[ jar ]---------------------------------
[INFO]
[INFO] --- maven-resources-plugin:3.1.0:resources (default-resources) @ demo ---
[INFO] Using 'UTF-8' encoding to copy filtered resources.
[INFO] Copying 1 resource

编译详细过程：https://share.weiyun.com/5qpaK3b

VS Code有些文件没有列出

比如.classpath，.project这些文件在VS Code里为啥没有显示呢

原因在于如下设置

{
    "java.configuration.updateBuildConfiguration": "interactive",
    "files.exclude": {
        "**/.classpath": true,
        "**/.project": true,
        "**/.settings": true,
        "**/.factorypath": true
    }
}

这些被排除了，所以不显示

完整工程

https://share.weiyun.com/5HMRKpg