问题
When I run ant it says:
Unable to locate tools.jar. Expected to find it in C:\Program Files\Java\jre6\lib\tools.jar
Buildfile: build.xml does not exist!
Build failed
What package can I use to download the file required > C:\Program Files\Java\jre6\lib\tools.jar
I just downloaded this one:
jre-6u19-windows-i586-s.exe
but unfortunately it appears that it was not on it...
回答1:
Java ships in 2 versions: JRE & SDK (used to be called JDK)
The JRE in addition to not containing the compiler, also doesn't contain all of the libraries available in the JDK (tools.jar is one of them)
When you download Java at: http://java.sun.com/javase/downloads/index.jsp, make sure to select the JDK version and install it. If you have both a JDK & JRE, make sure that ANT is using the JDK, you can check JAVA_HOME (environment variable), and on the commandline if you do "javac -version" you should get a version description.
回答2:
You need JDK for that.
Set JAVA_HOME to point to the JDK.
回答3:
Using suggestions from answers on this page and this other one (ANT_HOME is set incorrectly or ant could not be located), the ultimate fix was the following:
Adding a ANT_HOME environment variable that points to the ROOT directory of your Apache ant directory location. (Not the bin sub-dir!)
Adding a JAVA_HOME environment variable that points to the ROOT directory of your Java JDK (or SDK) directory location. (NOT your JRE and not the bin sub-dir!)
Appended %ANT_HOME%\bin;%JAVA_HOME%\bin to the PATH environment variable.
Make sure you close any command window(s) that were open prior to the changes above. Only command windows opened after the changes will have the updated environment variables.
回答4:
I was having the same problem, none of the posted solutions helped. Finally, I figured out what I was doing wrong. When I installed the Java JDK it asked me for a directiy where I wanted to install. I changed the directory to where I wanted the code to go. It then asked for a directory where it could install the Runtime Environment and I selected the SAME DIRECTORY where I installed the JDK. It over wrote my lib folder and erased the tools.jar. Be sure to use different folders during the install. I used my custom folder for the JDK and the default folder for the RE and everything worked fine.
回答5:
I found that even though my path is set to JDK, the ant wants the tools.jar from jre folder. So just copy paste the tools.jar folder from JDK to jre.
回答6:
I was also getting the same problem, but i uninstalled all updates of java and now it is working very fine....
回答7:
Just set your java_home property with java home (eg:C:\Program Files\Java\jdk1.7.0_25) directory. Close command prompt and reopen it. Then error relating to tools.jar will be solved. For the second one("build.xml not found ") you should have to ensure your command line also at the directory where your build.xml file resides.
回答8:
Sometimes while installing JDK, you may get a dll is missing error. Because of this, it won't copy the tools.jar file to the java folder. So please reinstall the JDK in a different location and if it is successful then you will see the tools.jar file.
来源：https://stackoverflow.com/questions/2618281/ant-error-when-trying-to-build-file-cant-find-tools-jar