文件行转换器

最近公司在做数据迁移,迁移脚本是在原有的基础上修改的.迁移完成之后,感觉脚本在格式上不是很美观,于是就在想能不能写一段程序进行格式化.恰好最近正在看<<企业集成模式>>,能否通过它的思想来完成这个事呢?

package com.app.common.util.file.transformer;

/**
 * 行转换器
 * 
 * @author Administrator
 * 
 */
public interface LineTransformation {

	public static final String EMPTY_STRING = "";

	public String transform(String line);

}

package com.app.common.util.file.transformer;

/**
 * 小写转换器
 * @author Administrator
 *
 */
public class LowerCaseTransformation implements LineTransformation {

	@Override
	public String transform(String line) {
		if (null == line) {
			return EMPTY_STRING;
		}
		return line.toLowerCase();
	}

}

package com.app.common.util.file.transformer;

/**
 * 大写转换器
 * @author Administrator
 *
 */
public class UpperCaseLineTransformation implements LineTransformation {

	@Override
	public String transform(String line) {
		if (null == line) {
			return EMPTY_STRING;
		}
		return line.toUpperCase();
	}

}

package com.app.common.util.file.transformer;

/**
 * trim转换器
 * @author Administrator
 *
 */
public class TrimLineTransformation implements LineTransformation {

	@Override
	public String transform(String line) {
		if (null == line) {
			return EMPTY_STRING;
		}
		return line.trim();
	}

}

package com.app.common.util.file.transformer;

import java.util.TreeMap;

/**
 * 行输入适配器
 * @author Administrator
 *
 */
public interface LineInAdapter {

	public static final TreeMap<Long, String> EMPTY_MAP = new TreeMap<Long, String>();

	public TreeMap<Long, String> doExecute();

}

package com.app.common.util.file.transformer;

import java.io.*;
import java.util.TreeMap;

/**
 * 文件行输入适配器
 * @author Administrator
 *
 */
public class FileLineInAdapter implements LineInAdapter {

	private File file;

	public FileLineInAdapter(File file) {
		if (null == file || !file.exists() || file.isDirectory()
				|| !file.canRead()) {
			throw new IllegalArgumentException(
					"file must exist,be a file and can read.");
		}
		this.file = file;
	}

	@Override
	public TreeMap<Long, String> doExecute() {
		BufferedReader reader = null;
		try {
			reader = new BufferedReader(new FileReader(this.file));
		} catch (FileNotFoundException e) {
		}
		if (null == reader) {
			return EMPTY_MAP;
		}
		TreeMap<Long, String> result = new TreeMap<Long, String>();
		Long lineNum = 1l;
		String line = null;
		try {
			while (null != (line = reader.readLine())) {
                result.put(lineNum++, line);
			}
		} catch (IOException e) {
		} finally {
			if (null != reader) {
				try {
					reader.close();
				} catch (IOException e) {
				}
			}
		}
		return result;
	}
}

package com.app.common.util.file.transformer;

import java.util.TreeMap;

/**
 * 行输出适配器
 * @author Administrator
 *
 */
public interface LineOutAdapter {

	public void doExecute(TreeMap<Long, String> lineMap);
}

package com.app.common.util.file.transformer;

import java.io.*;
import java.util.*;

/**
 * 文件行输出适配器
 * @author Administrator
 *
 */
public class FileLineOutAdapter implements LineOutAdapter {

	public static final String FILE_EXTENSION = ".";

	private File file;

	public FileLineOutAdapter(File file) {
		if (null == file) {
			throw new IllegalArgumentException("file can't be null.");
		}
		String filePath = null;
		try {
			filePath = file.getCanonicalPath();
		} catch (IOException e) {
		}
		if (null == filePath) {
			throw new IllegalArgumentException("can't get CanonicalPath.");
		}
		if (filePath.contains(FILE_EXTENSION) == false) {
			throw new IllegalArgumentException("file must be a file.");
		}
		this.file = file;
	}

	@Override
	public void doExecute(TreeMap<Long, String> lineMap) {
		if (null == lineMap || lineMap.isEmpty()) {
			return;
		}
		BufferedWriter writer = null;
		try {
			writer = new BufferedWriter(new FileWriter(this.file));
		} catch (IOException e) {
			e.printStackTrace();
		}
		if (null == writer) {
			return;
		}
		Collection<String> lines = lineMap.values();
		try {
			for (String line : lines) {
				writer.write(line);
				writer.newLine();
			}
			writer.flush();
		} catch (IOException e) {

		} finally {
			if (null != writer) {
				try {
					writer.close();
				} catch (IOException e) {
				}
			}
		}
	}

}

package com.app.common.util.file.transformer;

import java.util.List;
import java.util.TreeMap;

/**
 * 行处理器
 * 
 * @author Administrator
 * 
 */
public interface LineProcesser {

	public void setLineTransformations(List<LineTransformation> transformations);

	public TreeMap<Long, String> process(TreeMap<Long, String> lineMap);

}

package com.app.common.util.file.transformer;

import java.util.*;
import java.util.Map.Entry;

/**
 * 默认行处理器
 * @author Administrator
 *
 */
public class DefLineProcesser implements LineProcesser {

	private List<LineTransformation> transformations;

	public DefLineProcesser() {

	}

	public DefLineProcesser(List<LineTransformation> transformations) {
		this.setLineTransformations(transformations);
	}

	@Override
	public void setLineTransformations(List<LineTransformation> transformations) {

		this.transformations = transformations;
	}

	@Override
	public TreeMap<Long, String> process(TreeMap<Long, String> lineMap) {
		if (null == this.transformations || this.transformations.size() == 0) {
			throw new IllegalArgumentException(
					"please set transformations first.");
		}
		if (null == lineMap || lineMap.isEmpty()) {
			return new TreeMap<Long, String>();
		}
		TreeMap<Long, String> result = new TreeMap<Long, String>();
		Set<Entry<Long, String>> entries = lineMap.entrySet();
		for (Entry<Long, String> entry : entries) {
			String line = entry.getValue();
			for (LineTransformation transformation : this.transformations) {
				line = transformation.transform(line);
			}
			result.put(entry.getKey(), line);
		}
		return result;
	}
}

package com.app.common.util.file.transformer;

import java.io.File;
import java.util.ArrayList;
import java.util.List;
import java.util.TreeMap;

/**
 * 测试类
 * @author Administrator
 *
 */
public class TestLineProcesser {

	/**
	 * @param args
	 */
	public static void main(String[] args) {

		File inputFile = new File("c:/test/a.txt");
		File outFile = new File("c:/a.txt");

		LineProcesser processer = new DefLineProcesser();

		List<LineTransformation> transformations = new ArrayList<LineTransformation>();
		transformations.add(new TrimLineTransformation());
		transformations.add(new UpperCaseLineTransformation());

		processer.setLineTransformations(transformations);

		LineInAdapter inAdapter = new FileLineInAdapter(inputFile);

		TreeMap<Long, String> lineMap = processer
				.process(inAdapter.doExecute());

		LineOutAdapter outAdapter = new FileLineOutAdapter(outFile);

		outAdapter.doExecute(lineMap);

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

}

当然还可以编写其它的行转换器,只需要实现LineTransformation接口即可,再将其加入到行处理器中就可以了.