Spring导入到Eclipse时报错，显示

spring 3.2.4源代码自带的gradlew编译的，配置文件里写的是com.lowagie:itext 2.1.7报错总说找不到com.itextpdf:itextpdf:4.2.2这是为什么？其他版本的spring3源码也是这样

Total time: 39.844 secs

E:\workspace3\spring>gradlew build --stacktrace

:spring-context-support:compileJava

FAILURE: Build failed with an exception.

* What went wrong:
Could not resolve all dependencies for configuration ':spring-context-support:op
tional'.
> Could not find com.itextpdf:itextpdf:4.2.2.
  Required by:
      org.springframework:spring-context-support:3.2.4.RELEASE > com.lowagie:ite
xt:4.2.2

* Try:
Run with --info or --debug option to get more log output.

* Exception is:
org.gradle.api.artifacts.ResolveException: Could not resolve all dependencies fo
r configuration ':spring-context-support:optional'.
        at org.gradle.api.internal.artifacts.ivyservice.DefaultLenientConfigurat
ion.rethrowFailure(DefaultLenientConfiguration.java:55)
       
Caused by: org.gradle.api.internal.artifacts.ivyservice.ModuleVersionNotFoundExc
eption: Could not find com.itextpdf:itextpdf:4.2.2.
Required by:
    org.springframework:spring-context-support:3.2.4.RELEASE > com.lowagie:itext

    :4.2.2





    unresolved dependency - com.itextpdf itextpdf 4.2.2