Click "My Computer" with the right mouse button-> Attribute-> Advanced-> envionment variables

System variable->; New-> Variable name: JAVA_HOME variable value: d: \ program files \ Java \ JDK1.6.0 _12 (this is only my JDK installation path).

System variable->; Edit-> Variable name: the path is preceded by:% JAVA _ HOME% \ bin (if you already have a path item, you don't need to create another one, just follow it.

Add noodles, but use them; Separate from the previous item)

System variable->; New-> Variable name: classpath variable value:

. ; % JAVA _ HOME % \ lib% JAVA _ HOME % \ lib \ dt . jar； % JAVA _ HOME % \ lib \ tools.jar

Finally, test whether the environment variables are set successfully.

Type in the search box in the lower left corner.

Coal mine management bureau

return

Enter javac

If the following message appears

Usage: javac & lt source file >

Among them, possible options include:

-g Generate all debugging information

-g:none does not generate any debugging information.

-g:{lines, vars, source} only generates some debugging information.

-nowarn does not generate any warnings.

-verbose outputs a message about what the compiler is doing.

-deprecation output uses the source location of the expired API.

-class path & lt； Path > specifies the location to find user class files.

-CP & lt； Path > specifies the location to find user class files.

-source path & lt； Path > specifies where to find the input source file.

-boot class path & lt； Path > overwrites the location of the boot class file.

-ext dirs & lt； Directory > the location of the extended directory in cover the installation.

-Endorser < Directory > the location of the standard path that overrides the signature.

-d & lt； Directory > specifies the location where the generated class files are stored.

-encoding < code > specifies the character encoding used by the source file.

-source & lt； Version > provides source code compatibility with the specified version.

-target & lt； Version > generates a class file for a specific virtual machine version.

-Version version information

-help outputs a summary of standard options.

-X outputs a summary of non-standard options.

-J & lt； Logo > Pass pass directly to the runtime system.

Congratulations, your Java environment variables have been successfully configured!

If it appears,

"Javac" is not an internal or external command, nor is it a runnable program.

Or batch files.

Explain that there is an error in the configuration of Java environment variables this time. Check it carefully!