World Wind Java开发之六——解析shape文件（转）

http://blog.csdn.net/giser_whu/article/details/41647117

最近一直忙于导师项目的事情了，几天没更新了，昨天和今天研究了下WWJ解析shp文件的源代码，现在记录下，希望可以帮到更多的人！

上一篇博客：World Wind Java开发之五——读取本地shp文件只讲了如何加载shp文件，没有涉及到shp文件的解析，我们这篇博客紧接上一篇博客，利用WWJ来解析shp文件。首先来看用到的源码包和相关类，如下图所示。解析shp文件主要用到Shapefile(shapefile文件类)、ShapefileRecord（shape文件记录类）、DBaseRecord类以及DBaseField（字段类）

1、读取shapefile文件

由上图可以看出有要实例化一个shapefile对象有六种方法，以其中的两种为例，看下源码：

（1）

/**
     * Opens a Shapefile from an InputStream, and InputStreams to its optional
     * resources.
     * <p/>
     * The source Shapefile may be accompanied optional streams to an index
     * resource stream, an attribute resource stream, and a projection resource
     * stream. If any of these streams are null or cannot be read for any
     * reason, the Shapefile opens without that information.
     * <p/>
     * This throws an exception if the shapefile's coordinate system is
     * unsupported.
     *
     * @param shpStream
     *            the shapefile geometry file stream.
     * @param shxStream
     *            the index file stream, can be null.
     * @param dbfStream
     *            the attribute file stream, can be null.
     * @param prjStream
     *            the projection file stream, can be null.
     * @throws IllegalArgumentException
     *             if the shapefile geometry stream <code>shpStream</code> is
     *             null.
     * @throws WWRuntimeException
     *             if the shapefile cannot be opened for any reason, or if the
     *             shapefile's coordinate system is unsupported.
     */
    public Shapefile(InputStream shpStream, InputStream shxStream,
            InputStream dbfStream, InputStream prjStream)
    {
        this(shpStream, shxStream, dbfStream, prjStream, null);
    }

输入文件流分别对应着.shp .shx .dbf .prj文件

（2）

/**
     * Opens an Shapefile from a general source. The source type may be one of
     * the following:
     * <ul>
     * <li>{@link java.io.InputStream}</li>
     * <li>{@link java.net.URL}</li>
     * <li>{@link File}</li>
     * <li>{@link String} containing a valid URL description or a file or
     * resource name available on the classpath.</li>
     * </ul>
     * <p/>
     * The source Shapefile may be accompanied by an optional index file,
     * attribute file, and projection file. To be recognized by this Shapefile,
     * accompanying files must be in the same logical folder as the Shapefile,
     * have the same filename as the Shapefile, and have suffixes ".shx",
     * ".dbf", and ".prj" respectively. If any of these files do not exist, or
     * cannot be read for any reason, the Shapefile opens without that
     * information.
     * <p/>
     * This throws an exception if the shapefile's coordinate system is
     * unsupported, or if the shapefile's coordinate system is unsupported.
     *
     * @param source
     *            the source of the shapefile.
     * @throws IllegalArgumentException
     *             if the source is null or an empty string.
     * @throws WWRuntimeException
     *             if the shapefile cannot be opened for any reason.
     */
    public Shapefile(Object source)
    {
        this(source, null);
    }

这种方法秩序给出shp文件的路径即可，但是若只有shp文件，缺少shx等文件则无法解析shape文件。

根据以上两种方法来实例化一个shapefile对象，源码如下：

String shpFilePath = "D:\Users\wwj_data\states.shp";
        String shxFilePath = "D:\Users\wwj_data\states.shx";
        String dbfFilePath = "D:\Users\wwj_data\states.dbf";
        String prjFilePath = "D:\Users\wwj_data\states.prj";

        Shapefile shapefile = new Shapefile(shpFilePath);
        System.out.println(shapefile.getShapeType());

或者：---------------------------------------------------------------------------------------

String shpFilePath = "D:\Users\wwj_data\states.shp";
        String shxFilePath = "D:\Users\wwj_data\states.shx";
        String dbfFilePath = "D:\Users\wwj_data\states.dbf";
        String prjFilePath = "D:\Users\wwj_data\states.prj";

        InputStream shpInputStream = new FileInputStream(shpFilePath);
        InputStream shxInputStream = new FileInputStream(shxFilePath);
        InputStream dbfInputStream = new FileInputStream(dbfFilePath);
        InputStream prjInputStream = new FileInputStream(prjFilePath);

        // 实例化一个shapefile类
         Shapefile shapefile = new Shapefile(shpInputStream, shxInputStream,
         dbfInputStream, prjInputStream);
        System.out.println(shapefile.getShapeType()); // shape类型

 

这里需要说明的一点是，一开始的时候我是用的Shapefile(Object source)方法，但是报错：Source is NULL，不知是什么原因；用下面这种方法就可以，这个可以不必太纠结。

2、获取shapefile文件的属性表信息

在shapefile.java文件中可以找到 attributeFile字段，包含shapefile文件的属性信息，但是其权限是protected，只需在原java文件中添加一个方法返回改字段值即可。改完源码，重新导出jar文件覆盖引用即可。

protected DBaseFile             attributeFile;

/**
     *
     * @方法名称: getAttributesTable ；
     * @方法描述:  获取属性表 ；
     * @参数 ：@return
     * @返回类型: DBaseFile ；
     * @创建人：奔跑的鸡丝 ;
     * @创建时间：2014-12-1 下午12:55:33；
     * @throws
     */
    public DBaseFile getAttributesTable()
    {
        return this.attributeFile;
    }

获取属性表后，首先要获取属性表的基本信息，如：shape文件的类型、字段个数以及记录个数。另外输出所有字段名

// 获取shp属性表
    DBaseFile dBaseFile = shapefile.getAttributesTable();
    int fieldCount = dBaseFile.getNumberOfFields(); // 字段数
    int recordsCount = dBaseFile.getNumberOfRecords(); // 记录数
    System.out.println("字段数为：" + fieldCount);
    System.out.println("记录数为：" + recordsCount);
    System.out.println(shapefile.getShapeType()); // shape类型
    //获取字段集合
    DBaseField [] dBaseFields=dBaseFile.getFields();

    for (int i = 0; i < fieldCount; i++)
    {
        System.out.println(dBaseFields[i].getName());
    }

运行结果如下：

在ArcMap下打开shp文件的属性表，对比可知输出的结果是正确的。

3、获取字段值

// 解析shape文件
        try
        {
            while (shapefile.hasNext())
            {
                ShapefileRecord record = shapefile.nextRecord(); // 获取一条记录
                DBaseRecord dBaseRecord = record.getAttributes(); // 获取该记录的属性信息

                Object[] values = dBaseRecord.getValues().toArray();//获取字段值集合

                for (int i = 0; i < values.length; i++)
                {
                    System.out.println(values[i].toString());
                }
                System.out.println("------------------");
            }
        }
        catch (Exception e)
        {
            e.printStackTrace();
            System.out.println("解析shapefile文件出错！");
        }
        finally
        {
            WWIO.closeStream(shapefile, shpFilePath);
            WWIO.closeStream(shapefile, shxFilePath);
            WWIO.closeStream(shapefile, dbfFilePath);
            WWIO.closeStream(shapefile, prjFilePath);

        }

思路很简单：shapefile文件—>获取一条记录—>获取记录的属性信息-->获取字段值集合。但是有一个问题：不支持中文字段值

调整后运行结果如下：

ArcMap下的属性表如下图所示：

通过对比，发现字段值虽然都读取了，但是顺序却是乱的。目前还未发现是什么原因，下一篇博客再来解决这个问题字段值与字段不对应的问题。下面给出完整的代码：

/**
     * @方法名称: shapeFileReader ；
     * @方法描述: 读取sh文件 ；
     * @参数 ：@throws FileNotFoundException
     * @返回类型: void ；
     * @创建人：奔跑的鸡丝 ;
     * @创建时间：2014-12-1 下午12:50:11；
     * @throws
     */
    private void shapeFileReader() throws FileNotFoundException
    {
        String shpFilePath = "D:\Users\wwj_data\states.shp";
        String shxFilePath = "D:\Users\wwj_data\states.shx";
        String dbfFilePath = "D:\Users\wwj_data\states.dbf";
        String prjFilePath = "D:\Users\wwj_data\states.prj";

        InputStream shpInputStream = new FileInputStream(shpFilePath);
        InputStream shxInputStream = new FileInputStream(shxFilePath);
        InputStream dbfInputStream = new FileInputStream(dbfFilePath);
        InputStream prjInputStream = new FileInputStream(prjFilePath);

        // 实例化一个shapefile类
         Shapefile shapefile = new Shapefile(shpInputStream, shxInputStream,
         dbfInputStream, prjInputStream);


        // 获取shp属性表
        DBaseFile dBaseFile = shapefile.getAttributesTable();
        int fieldCount = dBaseFile.getNumberOfFields(); // 字段数
        int recordsCount = dBaseFile.getNumberOfRecords(); // 记录数
        System.out.println("字段数为：" + fieldCount);
        System.out.println("记录数为：" + recordsCount);
        System.out.println(shapefile.getShapeType()); // shape类型
        //获取字段集合
        DBaseField [] dBaseFields=dBaseFile.getFields();

        for (int i = 0; i < fieldCount; i++)
        {
            System.out.print(dBaseFields[i].getName()+"    ");
        }
        System.out.println();
        // 解析shape文件
        try
        {
            while (shapefile.hasNext())
            {
                ShapefileRecord record = shapefile.nextRecord(); // 获取一条记录
                DBaseRecord dBaseRecord = record.getAttributes(); // 获取该记录的属性信息

                Object[] values = dBaseRecord.getValues().toArray();//获取字段值集合

                for (int i = 0; i < values.length; i++)
                {
                    System.out.print(values[i].toString()+"        ");
                }
                System.out.println("------------------");
            }
        }
        catch (Exception e)
        {
            e.printStackTrace();
            System.out.println("解析shapefile文件出错！");
        }
        finally
        {
            WWIO.closeStream(shapefile, shpFilePath);
            WWIO.closeStream(shapefile, shxFilePath);
            WWIO.closeStream(shapefile, dbfFilePath);
            WWIO.closeStream(shapefile, prjFilePath);

        }

    }

-----------------------------------------------华丽的分割线----------------------------------------------

关于上面提到的获取的字段与字段值不对应的问题解决办法：根据字段名来获取字段值。

while (shapefile.hasNext())
            {
                ShapefileRecord record = shapefile.nextRecord(); // 获取一条记录
                DBaseRecord dBaseRecord = record.getAttributes(); // 获取该记录的属性信息
                ArrayList<String> fieldArrayList = new ArrayList<String>();
                for (int i = 0; i < fieldCount; i++)
                {
                    /**
                     * 根据字段名称来获取字段值
                     */
                    String fieldValue = dBaseRecord.getValue(
                            dBaseFields[i].getName()).toString(); //
                    fieldArrayList.add(fieldValue);
                    System.out.print(fieldValue + "        ");

                }

                System.out.println("------------------");
            }

执行结果如下图所示。

您好， shp 文件，属性值中文乱码问题，我是这么解决的
修改 gov.nasa.worldwind.formats.shapefile.DBaseFile;下的
decodeString 方法中的UTF-8 类型改为 GBK类型，希望对您有用