Question

JAVA如何将类存放到CSV文件

Answer 1

package cn.com.sunjapan.university.web;

import java.util.ArrayList;
import java.util.Vector;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import cn.com.sunjapan.comlib.exception.PJException;
import cn.com.sunjapan.framework.core.misc.ChainedException;

public class ParseCsvUtil {
	
	transient private static Log log = LogFactory.getLog(ParseCsvUtil.class);

	/** 屏蔽构造函数 */
    private ParseCsvUtil() {

    }

    /** 单子模式静态变量 */
    private static ParseCsvUtil instance;

    /**
     * 获取静态方法
     * 
     * @return 静态变量
     */
    public static synchronized ParseCsvUtil getInstance() {
        if (instance == null) {
            instance = new ParseCsvUtil();
        }
        return instance;
    }

    /**
     * 得到文件头的数据<br>
     * 
     * @param csvdata
     *            头文件信息
     * @return 头文件信息
     */
    public ArrayList<String> parseCsvHeadData(String[][] csvdata) {
        if (log.isDebugEnabled()) {
            log.debug("now we enter parseCsvHeadData of ParseCsvFileManager");
        }
        ArrayList<String> csvHeadList = new ArrayList<String>();
        for (int i = 0; i < csvdata[0].length; i++) {
            csvHeadList.add(csvdata[0][i]);
        }
        return csvHeadList;
    }

    /**
     * 得到文件内容的list<br>
     * 
     * @param csvdata
     *            文件内容
     * @return 文件内容
     */
    public ArrayList<String[]> parseCsvData(String[][] csvdata) {
        if (log.isDebugEnabled()) {
            log.debug("now we enter parseCsvData of ParseCsvFileManager");
        }
        ArrayList<String[]> csvList = new ArrayList<String[]>();
        for (int i = 1; i < csvdata.length; i++) {
            csvList.add(csvdata[i]);
        }
        return csvList;
    }
    
    /**
     * 解析csv文件一行数据
     * 
     * @param csvLine
     *            csv文件的一行数据
     * @return 解析后的字符串数组
     * @throws ChainedException
     *             抛出异常
     */
    public static String[] parseCsvLine(String csvLine) throws ChainedException {
        if (log.isDebugEnabled()) {
            log.debug("now we enter parseCsvLine of CSVFileParse");
        }
        String[] retArray = null;
        if (csvLine == null || csvLine.trim().length() <= 0) {
            return null;
        }
        StringBuffer sbuf = new StringBuffer();
        Vector<String> result = new Vector<String>();
        boolean beginWithQuote = false;

        int length = csvLine.length();
        for (int i = 0; i < length; i++) {
            char ch = csvLine.charAt(i);

            if (ch == '\"') {
                if (beginWithQuote) {
                    i++;

                    if (i >= length) {
                        result.addElement(sbuf.toString());
                        sbuf = new StringBuffer();
                        beginWithQuote = false;
                    } else {
                        ch = csvLine.charAt(i);
                        if (ch == '\"') {
                            sbuf.append(ch);
                        } else if (ch == ',') {
                            result.addElement(sbuf.toString());
                            sbuf = new StringBuffer();
                            beginWithQuote = false;
                        } else {
                            throw new ChainedException(
                                    "Single double-quote char mustn't exist in filed "
                                            + (result.size() + 1)
                                            + " while it is begined with quote\nchar at:"
                                            + i);
                        }
                    }
                } else if (sbuf.length() == 0) {
                    beginWithQuote = true;
                } else {
                    throw new ChainedException(
                            "Quote cannot exist in a filed which doesn't begin with quote!\nfield:"
                                    + (result.size() + 1));
                }
            } else if (ch == ',') {
                if (beginWithQuote) {
                    sbuf.append(ch);
                } else {
                    result.addElement(sbuf.toString());
                    sbuf = new StringBuffer();
                    beginWithQuote = false;
                }

            } else {
                sbuf.append(ch);
            }
        }

        if (sbuf.length() != 0) {
            if (beginWithQuote) {
                throw new ChainedException(
                        "last field is begin with but not end with double quote");
            } else {
                result.addElement(sbuf.toString());
            }
        }
        retArray = new String[result.size()];
        for (int i = 0; i < retArray.length; i++) {
            retArray[i] = (String) result.elementAt(i);
        }
        return retArray;
    }
    
    /**
     * 导出文件<br>
     * 
     * @param request
     *            HttpServletRequest
     * @return 导出文件
     * @throws ChainedException
     *             ChainedException
     */
    public ArrayList<String[]>  outFileList(String[][] content)
            throws ChainedException {
        if (log.isDebugEnabled()) {
            log.debug("now we enter outFileList of ParseCsvFileManager");
        }
        ArrayList<String[]>  list = new ArrayList<String[]> ();
        try {
            if (content.length > 0) {
                for (int i = 0; i < content.length; i++) {
                	String lineValue = "";
                	for(int x = 0; x < content[i].length; x++){
                		if(x == content[i].length - 1){
                			lineValue += content[i][x];
                		}else {
                			lineValue += content[i][x] + ",";
                		}
                	}
                	// 解析字符串把null替换成空的
                	String[] valueList = parseCsvLine(lineValue
                			.replaceAll("null", "")
                			+ ",");
                	list.add(valueList);
                }
            }
        } catch (PJException e) {
            // TODO 自动生成 catch 块
            e.printStackTrace();
        }
        return list;
    }
}

追问

可以详细的解释一下么，有些看不懂。