尝试使用java和clojure在eclipse中创建maven动态Web项目

Question

I have created maven-archetype-webapp project in Eclipse. And I want to use Clojure code in Java. So, there is my core.clj file:

(ns coq.core
 (:gen-class
   :name coq.core
    :methods [#^{:static true} [foo [int] void]]))

(defn -foo [i] (println "Hello from Clojure. My input was " i))

(defn -main [] (println "Hello from Clojure -main." ))

pom.xml:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>gleboGroup</groupId>
<artifactId>javaandclojure</artifactId>
<packaging>war</packaging>
<version>0.0.1-SNAPSHOT</version>
<name>javaandclojure Maven Webapp</name>
<url>http://maven.apache.org</url>
<dependencies>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>3.8.1</version>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>3.1-b02</version>
        <type>jar</type>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>org.clojure</groupId>
        <artifactId>clojure</artifactId>
        <version>1.3.0</version>
    </dependency>
</dependencies>
<build>
    <finalName>javaandclojure</finalName>
    <plugins>
        <plugin>
            <groupId>com.theoryinpractise</groupId>
            <artifactId>clojure-maven-plugin</artifactId>
            <version>1.3.10</version>
            <configuration>
                <sourceDirectories>
                    <sourceDirectory>src/main/clojure</sourceDirectory>
                </sourceDirectories>
                <testSourceDirectories>
                    <testSourceDirectory>src/test/clojure</testSourceDirectory>
                </testSourceDirectories>
            </configuration>
            <executions>
                <execution>
                    <id>compile</id>
                    <phase>compile</phase>
                    <goals>
                        <goal>compile</goal>
                    </goals>
                </execution>
                <execution>
                    <id>test</id>
                    <phase>test</phase>
                    <goals>
                        <goal>test</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
        <plugin>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>2.3.2</version>
            <executions>
                <execution>
                    <id>default-compile</id>
                    <phase>compile</phase>
                    <goals>
                        <goal>compile</goal>
                    </goals>
                </execution>
                <execution>
                    <id>default-testCompile</id>
                    <phase>test-compile</phase>
                    <goals>
                        <goal>testCompile</goal>
                    </goals>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

There is my single servlet with error on core.foo(123):

package com.javaandclojure;

import java.io.IOException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.ServletException;
import javax.servlet.http.*;

import coq.*;

@WebServlet({ "/*"})
public class Main extends HttpServlet {
    private static final long serialVersionUID = 1L;

    protected void doGet(HttpServletRequest request,
            HttpServletResponse response) throws ServletException, IOException {
        System.out.println("inside get!");
        core.foo(123);// core cannot be resolved
        request.setAttribute("number", 42);
        request.getRequestDispatcher("/index.jsp").forward(request, response);
    }
}

Some scrinshots from eclipse:

build path:

Maven Build with goals:" clean package" gives it:

[INFO] Scanning for projects...
[INFO]                                                                         
[INFO] ------------------------------------------------------------------------
[INFO] Building javaandclojure Maven Webapp 0.0.1-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO] 
[INFO] --- maven-clean-plugin:2.4.1:clean (default-clean) @ javaandclojure ---
[INFO] Deleting D:\porn\indigo\javaandclojure\target
[INFO] 
[INFO] --- maven-resources-plugin:2.4.3:resources (default-resources) @ javaandclojure ---
[WARNING] Using platform encoding (Cp1251 actually) to copy filtered resources, i.e. build is platform dependent!
[INFO] Copying 0 resource
[INFO] 
[INFO] --- maven-compiler-plugin:2.3.2:compile (default-compile) @ javaandclojure ---
[WARNING] File encoding has not been set, using platform encoding Cp1251, i.e. build is platform dependent!
[INFO] Compiling 1 source file to D:\porn\indigo\javaandclojure\target\classes
[INFO] -------------------------------------------------------------
[ERROR] COMPILATION ERROR : 
[INFO] -------------------------------------------------------------
[ERROR] \porn\indigo\javaandclojure\src\main\java\com\javaandclojure\Main.java:[10,10] error: package coq does not exist
[ERROR] \porn\indigo\javaandclojure\src\main\java\com\javaandclojure\Main.java:[17,2] error: cannot find symbol
[INFO] 2 errors 
[INFO] -------------------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2.042s
[INFO] Finished at: Sun Nov 11 16:28:25 EET 2012
[INFO] Final Memory: 8M/20M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-compiler-plugin:2.3.2:compile (default-compile) on project javaandclojure: Compilation failure: Compilation failure:
[ERROR] \porn\indigo\javaandclojure\src\main\java\com\javaandclojure\Main.java:[10,10] error: package coq does not exist
[ERROR] \porn\indigo\javaandclojure\src\main\java\com\javaandclojure\Main.java:[17,2] error: cannot find symbol
[ERROR] -> [Help 1]
[ERROR] 
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR] 
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoFailureException

Maybe I should have used another maven archetype?

Answer 1

That is because the Java compiler is being run before the clojure compiler.

If you force the Java compilation to take place after the clojure-maven-plugin it will work. Add these lines after the clojure-maven-plugin :

<plugin>
    <artifactId>maven-compiler-plugin</artifactId>
    <version>2.3.2</version>
    <executions>
        <execution>
            <id>default-compile</id>
            <phase>none</phase>
        </execution>
        <execution>
            <id>default-testCompile</id>
            <phase>none</phase>
        </execution>
        <execution>
            <id>java-compile</id>
            <phase>compile</phase>
            <goals>
                <goal>compile</goal>
            </goals>
        </execution>
        <execution>
            <id>java-testCompile</id>
            <phase>test-compile</phase>
            <goals>
                <goal>testCompile</goal>
            </goals>
        </execution>
    </executions>
</plugin>

Answer 2

I would suggest that you create a project with 2 modules so it is clear what depends on what. If your Java code has to depend on your Clojure code, then the java module (war?) should depend on the clojure module.