概述
对于一门技术，我们最先是了解它（what），然后再熟练的使用它（how）以及何时用它（when），最后肯定要看透它（why）。
spring作为Java开发人员可以说是最熟悉不过的了，基本每个Java的项目都会用到spring，阅读spring的源码，对于一个有理想的程序员来说，也是一件必干不可的事，阅读源码我们才能更好的使用它、理解它，在遇到问题的时候，我们才能更好的找到问题的原因，并高效的解决。
阅读源码的最好方式，就是下载下来然后导入到IDE，通过编写Test代码来Debug跟踪。spring源码导入到eclipse确实要花费一点功夫，容易出错，在这里记录一下。
基本步骤，如下：
- 去GitHub中下载spring framework的源码，https://github.com/spring-projects下载Spring其中的一个版本，本文下载的 Spring5.0.5 ;
- 安装Gradle软件，官网下载 https://downloads.gradle.org/distributions/gradle-4.0.1-all.zip解压，然后设置GRADLE_HOME和PATH；
- 命令行中运行gradle -v，检查一下是否正确安装配置；
- 命令行中运行spring framework根目录下的 import-into-eclipse.bat ，连续两次回车，就可以开始自动构建，如果过程中出现失败的情况，就要根据具体提示来解决了；中间出现停止不前的情况里，按ctrl+c终止，再运行就可以进行下去；过程需要花些时间（几个小时都有可能），视下载各种依赖jar包和dom文件的速度而定；
- 在Eclipse菜单File->import选择General下面的Exsiting projects into workspace，这样就导入完成了。
如果你按上述步骤能一次成功的话，那不仅是你运气，而且RP极高，反正我没有，而且还折腾了一下午的时间。
第一步：下载 spring 项目
下载后如下压缩包，解压即可。
第二步：下载 gradle 软件，配置环境变量。
第三步: 检查gradle软件是否安装成功。
第四步：构建项目
运行源码中的 import-into-eclipse.bat，来构建项目，
或者运行 进入spring源码目录执行：gradle eclipse -x :eclipse ，来构建项目。
-----------------------------------------------------------------------
Spring Framework - Eclipse/STS project import guide
This script will guide you through the process of importing the Spring
Framework projects into Eclipse or the Spring Tool Suite (STS). It is
recommended that you have a recent version of Eclipse or STS. As a bare
minimum you will need Eclipse with full Java 8 support, the AspectJ
Development Tools (AJDT), and the Groovy Compiler.
If you need to download and install Eclipse or STS, please do that now
by visiting one of the following sites:
- Eclipse downloads: http://download.eclipse.org/eclipse/downloads
- STS downloads: http://spring.io/tools/sts/all
- STS nightly builds: http://dist.springsource.com/snapshot/STS/nightly-distributions.html
- ADJT: http://www.eclipse.org/ajdt/downloads/
- Groovy Eclipse: https://github.com/groovy/groovy-eclipse/wiki
Otherwise, press enter and we'll begin.
请按任意键继续. . .
-----------------------------------------------------------------------
STEP 1: Generate subproject Eclipse metadata
The first step will be to generate Eclipse project metadata for each
of the spring-* subprojects. This happens via the built-in
"Gradle wrapper" script (./gradlew in this directory). If this is your
first time using the Gradle wrapper, this step may take a few minutes
while a Gradle distribution is downloaded for you.
The command run will be:
gradlew --no-daemon cleanEclipse :spring-oxm:compileTestJava eclipse -x :eclipse
Press enter when ready.
请按任意键继续. . .
:buildSrc:clean
:buildSrc:compileJava NO-SOURCE
:buildSrc:compileGroovy
:buildSrc:processResources
:buildSrc:classes
:buildSrc:jar
:buildSrc:assemble
:buildSrc:compileTestJava NO-SOURCE
:buildSrc:compileTestGroovy NO-SOURCE
:buildSrc:processTestResources NO-SOURCE
:buildSrc:testClasses UP-TO-DATE
:buildSrc:test NO-SOURCE
:buildSrc:check UP-TO-DATE
:buildSrc:build
Download https://plugins.gradle.org/m2/org/jetbrains/dokka/org.jetbrains.dokka.gradle.plugin/0.9.15/org.jetbrains.dokka.
gradle.plugin-0.9.15.pom
Download https://jcenter.bintray.com/org/jetbrains/dokka/dokka-gradle-plugin/0.9.15/dokka-gradle-plugin-0.9.15.pom
Download https://jcenter.bintray.com/org/jetbrains/kotlin/kotlin-runtime/1.0.7/kotlin-runtime-1.0.7.pom
Download https://jcenter.bintray.com/org/jetbrains/kotlin/kotlin-project/1.0.7/kotlin-project-1.0.7.pom
Download https://jcenter.bintray.com/org/jetbrains/kotlin/kotlin-reflect/1.0.7/kotlin-reflect-1.0.7.pom
Download https://jcenter.bintray.com/org/jetbrains/kotlin/kotlin-runtime/1.0.7/kotlin-runtime-1.0.7.jar
Download https://jcenter.bintray.com/org/jetbrains/dokka/dokka-gradle-plugin/0.9.15/dokka-gradle-plugin-0.9.15.jar
:cleanEclipseClasspath UP-TO-DATE
:cleanEclipseJdt UP-TO-DATE
:cleanEclipseJdtUi UP-TO-DATE
:cleanEclipseProject UP-TO-DATE
:cleanEclipse UP-TO-DATE
:spring-aop:cleanEclipseClasspath UP-TO-DATE
:spring-aop:cleanEclipseJdt UP-TO-DATE
:spring-aop:cleanEclipseJdtUi UP-TO-DATE
:spring-aop:cleanEclipseProject UP-TO-DATE
:spring-aop:cleanEclipse UP-TO-DATE
:spring-aspects:cleanEclipseClasspath UP-TO-DATE
:spring-aspects:cleanEclipseJdt UP-TO-DATE
:spring-aspects:cleanEclipseJdtUi UP-TO-DATE
:spring-aspects:cleanEclipseProject UP-TO-DATE
:spring-aspects:cleanEclipse UP-TO-DATE
:spring-beans:cleanEclipseClasspath UP-TO-DATE
:spring-beans:cleanEclipseJdt UP-TO-DATE
:spring-beans:cleanEclipseJdtUi UP-TO-DATE
:spring-beans:cleanEclipseProject UP-TO-DATE
:spring-beans:cleanEclipse UP-TO-DATE
:spring-build-src:cleanEclipseClasspath UP-TO-DATE
:spring-build-src:cleanEclipseJdt UP-TO-DATE
:spring-build-src:cleanEclipseJdtUi UP-TO-DATE
:spring-build-src:cleanEclipseProject UP-TO-DATE
:spring-build-src:cleanEclipse UP-TO-DATE
:spring-context:cleanEclipseClasspath UP-TO-DATE
:spring-context:cleanEclipseJdt UP-TO-DATE
:spring-context:cleanEclipseJdtUi UP-TO-DATE
:spring-context:cleanEclipseProject UP-TO-DATE
:spring-context:cleanEclipse UP-TO-DATE
:spring-context-indexer:cleanEclipseClasspath UP-TO-DATE
:spring-context-indexer:cleanEclipseJdt UP-TO-DATE
:spring-context-indexer:cleanEclipseJdtUi UP-TO-DATE
:spring-context-indexer:cleanEclipseProject UP-TO-DATE
:spring-context-indexer:cleanEclipse UP-TO-DATE
:spring-context-support:cleanEclipseClasspath UP-TO-DATE
:spring-context-support:cleanEclipseJdt UP-TO-DATE
:spring-context-support:cleanEclipseJdtUi UP-TO-DATE
:spring-context-support:cleanEclipseProject UP-TO-DATE
:spring-context-support:cleanEclipse UP-TO-DATE
:spring-core:cleanEclipseClasspath UP-TO-DATE
:spring-core:cleanEclipseJdt UP-TO-DATE
:spring-core:cleanEclipseJdtUi UP-TO-DATE
:spring-core:cleanEclipseProject UP-TO-DATE
:spring-core:cleanEclipse UP-TO-DATE
:spring-expression:cleanEclipseClasspath UP-TO-DATE
:spring-expression:cleanEclipseJdt UP-TO-DATE
:spring-expression:cleanEclipseJdtUi UP-TO-DATE
:spring-expression:cleanEclipseProject UP-TO-DATE
:spring-expression:cleanEclipse UP-TO-DATE
:spring-framework-bom:cleanEclipseClasspath UP-TO-DATE
:spring-framework-bom:cleanEclipseJdt UP-TO-DATE
:spring-framework-bom:cleanEclipseJdtUi UP-TO-DATE
:spring-framework-bom:cleanEclipseProject UP-TO-DATE
:spring-framework-bom:cleanEclipse UP-TO-DATE
:spring-instrument:cleanEclipseClasspath UP-TO-DATE
:spring-instrument:cleanEclipseJdt UP-TO-DATE
:spring-instrument:cleanEclipseJdtUi UP-TO-DATE
:spring-instrument:cleanEclipseProject UP-TO-DATE
:spring-instrument:cleanEclipse UP-TO-DATE
:spring-jcl:cleanEclipseClasspath UP-TO-DATE
:spring-jcl:cleanEclipseJdt UP-TO-DATE
:spring-jcl:cleanEclipseJdtUi UP-TO-DATE
:spring-jcl:cleanEclipseProject UP-TO-DATE
:spring-jcl:cleanEclipse UP-TO-DATE
:spring-jdbc:cleanEclipseClasspath UP-TO-DATE
:spring-jdbc:cleanEclipseJdt UP-TO-DATE
:spring-jdbc:cleanEclipseJdtUi UP-TO-DATE
:spring-jdbc:cleanEclipseProject UP-TO-DATE
:spring-jdbc:cleanEclipse UP-TO-DATE
:spring-jms:cleanEclipseClasspath UP-TO-DATE
:spring-jms:cleanEclipseJdt UP-TO-DATE
:spring-jms:cleanEclipseJdtUi UP-TO-DATE
:spring-jms:cleanEclipseProject UP-TO-DATE
:spring-jms:cleanEclipse UP-TO-DATE
:spring-messaging:cleanEclipseClasspath UP-TO-DATE
:spring-messaging:cleanEclipseJdt UP-TO-DATE
:spring-messaging:cleanEclipseJdtUi UP-TO-DATE
:spring-messaging:cleanEclipseProject UP-TO-DATE
:spring-messaging:cleanEclipse UP-TO-DATE
:spring-orm:cleanEclipseClasspath UP-TO-DATE
:spring-orm:cleanEclipseJdt UP-TO-DATE
:spring-orm:cleanEclipseJdtUi UP-TO-DATE
:spring-orm:cleanEclipseProject UP-TO-DATE
:spring-orm:cleanEclipse UP-TO-DATE
:spring-oxm:cleanEclipseClasspath UP-TO-DATE
:spring-oxm:cleanEclipseJdt UP-TO-DATE
:spring-oxm:cleanEclipseJdtUi UP-TO-DATE
:spring-oxm:cleanEclipseProject UP-TO-DATE
:spring-oxm:cleanEclipse UP-TO-DATE
:spring-test:cleanEclipseClasspath UP-TO-DATE
:spring-test:cleanEclipseJdt UP-TO-DATE
:spring-test:cleanEclipseJdtUi UP-TO-DATE
:spring-test:cleanEclipseProject UP-TO-DATE
:spring-test:cleanEclipse UP-TO-DATE
:spring-tx:cleanEclipseClasspath UP-TO-DATE
:spring-tx:cleanEclipseJdt UP-TO-DATE
:spring-tx:cleanEclipseJdtUi UP-TO-DATE
:spring-tx:cleanEclipseProject UP-TO-DATE
:spring-tx:cleanEclipse UP-TO-DATE
:spring-web:cleanEclipseClasspath UP-TO-DATE
:spring-web:cleanEclipseJdt UP-TO-DATE
:spring-web:cleanEclipseJdtUi UP-TO-DATE
:spring-web:cleanEclipseProject UP-TO-DATE
:spring-web:cleanEclipse UP-TO-DATE
:spring-webflux:cleanEclipseClasspath UP-TO-DATE
:spring-webflux:cleanEclipseJdt UP-TO-DATE
:spring-webflux:cleanEclipseJdtUi UP-TO-DATE
:spring-webflux:cleanEclipseProject UP-TO-DATE
:spring-webflux:cleanEclipse UP-TO-DATE
:spring-webmvc:cleanEclipseClasspath UP-TO-DATE
:spring-webmvc:cleanEclipseJdt UP-TO-DATE
:spring-webmvc:cleanEclipseJdtUi UP-TO-DATE
:spring-webmvc:cleanEclipseProject UP-TO-DATE
:spring-webmvc:cleanEclipse UP-TO-DATE
:spring-websocket:cleanEclipseClasspath UP-TO-DATE
:spring-websocket:cleanEclipseJdt UP-TO-DATE
:spring-websocket:cleanEclipseJdtUi UP-TO-DATE
:spring-websocket:cleanEclipseProject UP-TO-DATE
:spring-websocket:cleanEclipse UP-TO-DATE
:spring-core:cglibRepackJar
Download https://repo.spring.io/libs-release/com/googlecode/jarjar/jarjar/1.3/jarjar-1.3.pom
Download https://repo.spring.io/libs-release/org/sonatype/oss/oss-parent/7/oss-parent-7.pom
Download https://repo.spring.io/libs-release/com/googlecode/jarjar/jarjar/1.3/jarjar-1.3.jar
Download https://repo.spring.io/libs-release/cglib/cglib/3.2.6/cglib-3.2.6.pom
Download https://repo.spring.io/libs-release/cglib/cglib-parent/3.2.6/cglib-parent-3.2.6.pom
Download https://repo.spring.io/libs-release/cglib/cglib/3.2.6/cglib-3.2.6.jar
:spring-core:objenesisRepackJar
:spring-jcl:compileKotlin
Download https://repo.spring.io/libs-release/com/google/code/findbugs/jsr305/3.0.2/jsr305-3.0.2.pom
Download https://repo.spring.io/libs-release/com/google/code/findbugs/jsr305/3.0.2/jsr305-3.0.2.jar
Download https://repo.spring.io/libs-release/org/slf4j/slf4j-parent/1.7.25/slf4j-parent-1.7.25.pom
:spring-jcl:compileKotlin FAILED
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':spring-jcl:compileKotlin'.
> Could not resolve all files for configuration ':spring-jcl:optional'.
> Could not resolve org.apache.logging.log4j:log4j-api:2.10.0.
Required by:
project :spring-jcl
> Could not resolve org.apache.logging.log4j:log4j-api:2.10.0.
> Could not get resource 'https://repo.spring.io/libs-release/org/apache/logging/log4j/log4j-api/2.10.0/log4j-a
pi-2.10.0.pom'.
> Could not GET 'https://repo.spring.io/libs-release/org/apache/logging/log4j/log4j-api/2.10.0/log4j-api-2.1
0.0.pom'.
> Connect to repo.spring.io:443 [repo.spring.io/35.186.232.213] failed: Connection timed out: connect
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with
--scan to get full insights.
* Get more help at https://help.gradle.org
BUILD FAILED in 1m 39s
99 actionable tasks: 3 executed, 96 up-to-date
D:\f\src\spring-framework-master>上面的提示，告诉我们依赖包下载失败了，这个会影响导入工程后spring项目中缺少jar包的支持，根据提示解决即可。
第五步：导入eclipse
若eclipse没有安装gradle插件，那么安装一下即可，
操作如下：
打开eclipse，Help——Marketplace，搜索buildship，进行安装。安装成功后会重启eclipse。
点完成后等待如下界面，
