java - 在 ant 脚本中包含外部 JAR 时出错

Question

这是我第一次尝试编写 ANT 脚本。这是我使用 Spring 的简单 Hello World 应用程序的 build.xml。

<project name="MyFirstApp" default="jar" basedir="..">  
    <property name="src" location="src"/>
    <property name="build" location="build"/>
    <property name="lib" location="/WebContent/WEB-INF/lib"/>   
    <path id="classpath-example">   
        <fileset dir="${build}" includes="*.jar"/>
    </path>
    <target name="clean">
        <delete dir="build"/>
    </target>
    <target name="compile">
        <mkdir dir="build/classes"/>
        <javac srcdir="${src}" destdir="build/classes" includeantruntime="false"/>
        <classpath refid="classpath-example"/>
    </target>
    <target name="jar">
        <mkdir dir="build/jar"/>
        <jar destfile="build/jar/MyFirstApp.jar" basedir="build/classes"/>          
    </target>
    <target name="run">
        <java jar="build/jar/MyFirstApp.jar" fork="true"/>
    </target>
</project>

当我尝试运行它时，会显示以下错误消息。

问题:无法创建任务或键入类路径原因:名称未定义。行动:检查拼写。操作:检查是否已声明任何自定义任务/类型。行动:检查任何/声明是否已经发生。

有人可以告诉我要做什么吗？

我第一次运行 ANT 脚本时，生成了 JAR 文件。当我再次尝试运行它时，它给出了下面提到的错误。

清洁: [delete] 删除目录F:\shil\JAVA\Spring Workspace\myfirstapp1\build

compile:
     [echo] compiling
    [mkdir] Created dir: F:\shil\JAVA\Spring Workspace\myfirstapp1\build\classes

    [javac] Compiling 5 source files to F:\shil\JAVA\Spring Workspace\myfirstapp
1\build\classes
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Hello
WorldServlet.java:4: package javax.servlet does not exist
    [javac] import javax.servlet.ServletException;
    [javac]                     ^
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Hello
WorldServlet.java:5: package javax.servlet.http does not exist
    [javac] import javax.servlet.http.HttpServlet;
    [javac]                          ^
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Hello
WorldServlet.java:6: package javax.servlet.http does not exist
    [javac] import javax.servlet.http.HttpServletRequest;
    [javac]                          ^
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Hello
WorldServlet.java:7: package javax.servlet.http does not exist
    [javac] import javax.servlet.http.HttpServletResponse;
    [javac]                          ^
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Hello
WorldServlet.java:12: cannot find symbol
    [javac] symbol: class HttpServlet
    [javac] public class HelloWorldServlet extends HttpServlet {
    [javac]                                        ^
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Hello
WorldServlet.java:26: cannot find symbol
    [javac] symbol  : class HttpServletRequest
    [javac] location: class my.hello.servlet.HelloWorldServlet
    [javac]     protected void doGet(HttpServletRequest request, HttpServletResp
onse response) throws ServletException, IOException {
    [javac]                          ^
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Hello
WorldServlet.java:26: cannot find symbol
    [javac] symbol  : class HttpServletResponse
    [javac] location: class my.hello.servlet.HelloWorldServlet
    [javac]     protected void doGet(HttpServletRequest request, HttpServletResp
onse response) throws ServletException, IOException {
    [javac]                                                      ^
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Hello
WorldServlet.java:26: cannot find symbol
    [javac] symbol  : class ServletException
    [javac] location: class my.hello.servlet.HelloWorldServlet
    [javac]     protected void doGet(HttpServletRequest request, HttpServletResp
onse response) throws ServletException, IOException {
    [javac]
                      ^
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Hello
WorldServlet.java:33: cannot find symbol
    [javac] symbol  : class HttpServletRequest
    [javac] location: class my.hello.servlet.HelloWorldServlet
    [javac]     protected void doPost(HttpServletRequest request, HttpServletRes
ponse response) throws ServletException, IOException {
    [javac]                           ^
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Hello
WorldServlet.java:33: cannot find symbol
    [javac] symbol  : class HttpServletResponse
    [javac] location: class my.hello.servlet.HelloWorldServlet
    [javac]     protected void doPost(HttpServletRequest request, HttpServletRes
ponse response) throws ServletException, IOException {
    [javac]                                                       ^
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Hello
WorldServlet.java:33: cannot find symbol
    [javac] symbol  : class ServletException
    [javac] location: class my.hello.servlet.HelloWorldServlet
    [javac]     protected void doPost(HttpServletRequest request, HttpServletRes
ponse response) throws ServletException, IOException {
    [javac]
                       ^
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Welco
meServlet.java:4: package javax.servlet does not exist
    [javac] import javax.servlet.RequestDispatcher;
    [javac]                     ^
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Welco
meServlet.java:5: package javax.servlet does not exist
    [javac] import javax.servlet.ServletException;
    [javac]                     ^
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Welco
meServlet.java:6: package javax.servlet.http does not exist
    [javac] import javax.servlet.http.HttpServlet;
    [javac]                          ^
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Welco
meServlet.java:7: package javax.servlet.http does not exist
    [javac] import javax.servlet.http.HttpServletRequest;
    [javac]                          ^
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Welco
meServlet.java:8: package javax.servlet.http does not exist
    [javac] import javax.servlet.http.HttpServletResponse;
    [javac]                          ^
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Welco
meServlet.java:15: cannot find symbol
    [javac] symbol: class HttpServlet
    [javac] public class WelcomeServlet extends HttpServlet {
    [javac]                                     ^
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Welco
meServlet.java:29: cannot find symbol
    [javac] symbol  : class HttpServletRequest
    [javac] location: class my.hello.servlet.WelcomeServlet
    [javac]     protected void doGet(HttpServletRequest request, HttpServletResp
onse response) throws ServletException, IOException {
    [javac]                          ^
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Welco
meServlet.java:29: cannot find symbol
    [javac] symbol  : class HttpServletResponse
    [javac] location: class my.hello.servlet.WelcomeServlet
    [javac]     protected void doGet(HttpServletRequest request, HttpServletResp
onse response) throws ServletException, IOException {
    [javac]                                                      ^
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Welco
meServlet.java:29: cannot find symbol
    [javac] symbol  : class ServletException
    [javac] location: class my.hello.servlet.WelcomeServlet
    [javac]     protected void doGet(HttpServletRequest request, HttpServletResp
onse response) throws ServletException, IOException {
    [javac]
                      ^
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Welco
meServlet.java:36: cannot find symbol
    [javac] symbol  : class HttpServletRequest
    [javac] location: class my.hello.servlet.WelcomeServlet
    [javac]     protected void doPost(HttpServletRequest request, HttpServletRes
ponse response) throws ServletException, IOException {
    [javac]                           ^
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Welco
meServlet.java:36: cannot find symbol
    [javac] symbol  : class HttpServletResponse
    [javac] location: class my.hello.servlet.WelcomeServlet
    [javac]     protected void doPost(HttpServletRequest request, HttpServletRes
ponse response) throws ServletException, IOException {
    [javac]                                                       ^
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Welco
meServlet.java:36: cannot find symbol
    [javac] symbol  : class ServletException
    [javac] location: class my.hello.servlet.WelcomeServlet
    [javac]     protected void doPost(HttpServletRequest request, HttpServletRes
ponse response) throws ServletException, IOException {
    [javac]
                       ^
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Welco
meServlet.java:41: cannot find symbol
    [javac] symbol  : class RequestDispatcher
    [javac] location: class my.hello.servlet.WelcomeServlet
    [javac]             RequestDispatcher welcomeDispatcher = getServletContext(
).getRequestDispatcher("/Welcome.jsp");
    [javac]             ^
    [javac] F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\servlet\Welco
meServlet.java:41: cannot find symbol
    [javac] symbol  : method getServletContext()
    [javac] location: class my.hello.servlet.WelcomeServlet
    [javac]             RequestDispatcher welcomeDispatcher = getServletContext(
).getRequestDispatcher("/Welcome.jsp");
    [javac]                                                   ^
    [javac] Note: F:\shil\JAVA\Spring Workspace\myfirstapp1\src\my\hello\HelloWo
rldApp.java uses or overrides a deprecated API.
    [javac] Note: Recompile with -Xlint:deprecation for details.
    [javac] 25 errors

BUILD FAILED
F:\shil\JAVA\Spring Workspace\myfirstapp1\ant\build.xml:19: Compile failed; see
the compiler error output for details.

Total time: 1 second

为什么这不是第一次发生？有人可以帮忙吗？

Answer 1

<classpath>在你的里面compile目标应该嵌套在 <javac> 中元素。

还值得注意的是，ant(事实上，大多数构建系统)的很多功能都来自于声明目标之间的依赖关系。在您的示例中，运行 jar 没有任何意义。没有先运行 compile 的目标目标，否则，没有要 jar 的类文件 - 或者更糟的是，您将运行 jar手动，但忘记运行 compile首先并以 JAR 文件中的过时类结束。所以，jar目标应该取决于 compile目标。这样，无论何时运行 jar目标，任何更改的类将首先自动编译。同样，run目标应该取决于 jar目标。