win7下在eclipse3.7中使用hadoop1.2.1插件运行MadReduce例子

环境 win7+hadoop_1.2.1+eclipse 3.7+maven 3

1.在win7下下载hadoop_1.2.1

2.安装hadoop的eclipse插件，注意eclipse 4.x版本下，hadoop插件会有问题，一定不能用4.x版本的eclipse，我用的是eclipse Indigo 也就是3.7 版本。

我有一个视频：http://pan.baidu.com/s/1sjUhsh3，讲的是安装配置eclipse插件

3.重新编译hadoop的hadoop-1.2.1\src\core\org\apache\hadoop\fs\FileUtil.java。

视频：http://pan.baidu.com/s/1gdVhCOV 讲的是如何导入hadoop源码到eclipse

在博客 http://blog.csdn.net/poisonchry/article/details/27535333 中讲到，需要修改 hadoop-1.2.1\src\core\org\apache\hadoop\fs\ 下的FileUtil.java。改动是：

private static void checkReturnValue(boolean rv, File p,
                                    FsPermission permission)
                                throws IOException
{
    /**
    * 把整个方法体注释了

    if (!rv)
    {
        throw new IOException("Failed to set permissions of path: " + p +
                        " to " +
                        String.format("%04o", permission.toShort()));
    }
    */
}

不知道怎么回事，我在eclipse中直接export jar包总是出错，没有关系，进入eclipse的workspace，找到hadoop源码的那个项目，进入bin文件夹，找到 core\org\apache\hadoop\fs\FileUtil.class文件，进入win7下 hadoop1.2.1的目录，用winRAR打开hadoop-core-1.2.1.jar文件，把刚刚的core\org\apache\hadoop\fs\FileUtil.class拷贝到对应的位置就好了

4. 新建一个maven项目，pom文件如下:

<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/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>cn.howso</groupId>
    <artifactId>hadoopmaven</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <hadoop.version>1.2.1</hadoop.version>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-client</artifactId>
            <version>${hadoop.version}</version>
        </dependency>

        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-core</artifactId>
            <version>${hadoop.version}</version>
            <scope>system</scope>
            <systemPath>C:\hadoop\hadoop-1.2.1\hadoop-core-1.2.1.jar</systemPath>
        </dependency>

        <dependency>
            <groupId>org.codehaus.jackson</groupId>
            <artifactId>jackson-mapper-asl</artifactId>
            <version>1.8.8</version>
        </dependency>
        <dependency>
            <groupId>org.codehaus.jackson</groupId>
            <artifactId>jackson-core-asl</artifactId>
            <version>1.8.8</version>
        </dependency>
        <dependency>
            <groupId>commons-httpclient</groupId>
            <artifactId>commons-httpclient</artifactId>
            <version>3.0.1</version>
        </dependency>

        <dependency>
            <groupId>commons-cli</groupId>
            <artifactId>commons-cli</artifactId>
            <version>1.2</version>
        </dependency>
        <dependency>
            <groupId>commons-configuration</groupId>
            <artifactId>commons-configuration</artifactId>
            <version>1.6</version>
        </dependency>

        <dependency>
            <groupId>org.hamcrest</groupId>
            <artifactId>hamcrest-all</artifactId>
            <version>1.1</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.apache.mrunit</groupId>
            <artifactId>mrunit</artifactId>
            <version>1.1.0</version>
            <classifier>hadoop2</classifier>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-minicluster</artifactId>
            <version>${hadoop.version}</version>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-test</artifactId>
            <version>${hadoop.version}</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>com.sun.jersey</groupId>
            <artifactId>jersey-core</artifactId>
            <version>1.8</version>
            <scope>test</scope>
        </dependency>

    </dependencies>
    <build>
        <finalName>hadoopx</finalName>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compilter-plugin</artifactId>
                <version>3.1</version>
                <configuration>
                    <source>1.7</source>
                    <target>1.7</target>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-jar-plugin</artifactId>
                <version>2.5</version>
                <configuration>
                    <outputDirectory>basedir</outputDirectory>
                    <archive>
                        <manifest>
                            <mainClass>hadoopmaven.Driver</mainClass>
                        </manifest>
                    </archive>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

当中的groupId，artifactId等等当然是根据各自项目命名的，当然对项目本身没有影响。

注意到对应hadoop-core的依赖，我写的是依赖本地系统的jar包，也就是刚刚被修改过的hadoop-core-1.2.1.jar文件。

5.随便写个什么mapreduce,我是按照博客 http://www.cnblogs.com/formyjava/p/5219191.html 中的写法，然后直接运行Driver类，或者右击Driver类，选择Run as ---> Run on hadoop就可以了