VS Code开发Java笔记

前提

确认本机已安装 JAVA SDK
确认本机已安装Maven
确认本机已安装Tomcat

比如我的环境


C:Program FilesJavajdk1.8.0_211
C:Program FilesJavajre1.8.0_211
D:Mavenapache-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./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./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./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./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./POM/4.0.0' xmlns:xsi='http://www./2001/XMLSchema-instance'
	xsi:schemaLocation='http://maven./POM/4.0.0 http://maven./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./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:Mavenapache-maven-3.6.1confsettings.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:Developdemo> cmd /c 'D:Mavenapache-maven-3.6.1binmvn.cmd' install -f 'd:Developdemopom.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./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./5HMRKpg

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