这个是某位大神写的，我拿来参考的，虽然最后没用上，不过还是记录一下

package ibp.common.report;import java.awt.BasicStroke;import java.awt.Color;import java.awt.Font;import java.awt.FontMetrics;import java.awt.Graphics2D;import java.awt.image.BufferedImage;import java.io.ByteArrayOutputStream;import java.io.File;import java.text.DecimalFormat;import java.util.ArrayList;import java.util.List;import javax.imageio.ImageIO;import org.apache.poi.hssf.usermodel.HSSFCell;import org.apache.poi.ss.usermodel.CellStyle;import org.apache.poi.ss.usermodel.Sheet;import org.apache.poi.ss.usermodel.Workbook;import org.apache.poi.ss.util.CellRangeAddress;import org.apache.poi.xssf.usermodel.XSSFFont;import sun.awt.SunHints;public class TransToImgUtil {    public static ByteArrayOutputStream FromExcelToImg(Workbook wb,String sheetName) throws Exception{        // 给定两个初始值，标志出导出区域，两个行列组合的单元格        int[] fromIndex = { 0, 0 };        int[] toIndex = { 17, 3 };         int imageWidth = 0;        int imageHeight = 0;        Sheet sheet = wb.getSheet(sheetName);        List
     
       rangeAddress = sheet.getMergedRegions(); // 获取整个sheet中合并单元格组合的集合         // 首先做初步的边界检测，如果指定区域是不合法的则抛出异常        int rowSum = sheet.getPhysicalNumberOfRows();        int colSum = sheet.getRow(0).getPhysicalNumberOfCells();        if (fromIndex[0] > rowSum || fromIndex[0] > toIndex[0] || toIndex[0] > rowSum) {            throw new Exception("the rowIndex of the area is wrong!");        }        if (fromIndex[1] > colSum || fromIndex[1] > toIndex[1] || toIndex[1] > colSum) {            throw new Exception("the colIndex of the area is wrong!");        }         // 计算实际需要载入内存的二维Cell数组的大小，剔除隐藏行列        int rowSize = toIndex[0]+1;        int colSize = toIndex[1]+1;         // 遍历需要扫描的区域                 UserCell[][] cells = new UserCell[rowSize][colSize];        int[] rowPixPos = new int[rowSize + 1];        rowPixPos[0] = 0;        int[] colPixPos = new int[colSize + 1];        colPixPos[0] = 0;        for (int i = 0; i < rowSize; i++) {             for (int j = 0; j < colSize; j++) {                 cells[i][j] = new UserCell();                cells[i][j].setCell(sheet.getRow(i).getCell(j));                cells[i][j].setRow(i);                cells[i][j].setCol(j);                boolean ifShow=(i>=fromIndex[0]) && (j>=fromIndex[1]);    //首先行列要在指定区域之间                ifShow=ifShow && !(sheet.isColumnHidden(j) || sheet.getRow(i).getZeroHeight()); //其次行列不可以隐藏                cells[i][j].setShow(ifShow);                 // 计算所求区域宽度                float widthPix = !ifShow ? 0 : sheet.getColumnWidthInPixels(j); // 如果该单元格是隐藏的，则置宽度为0                if (i == fromIndex[0]) {                    imageWidth += widthPix;                }                                 colPixPos[j+1] = (int) (widthPix * 1.15 + colPixPos[j]);             }             // 计算所求区域高度            boolean ifShow=(i>=fromIndex[0]);    //行序列在指定区域中间            ifShow=ifShow && !sheet.getRow(i).getZeroHeight();  //行序列不能隐藏            float heightPoint = !ifShow ? 0 : sheet.getRow(i).getHeightInPoints(); // 如果该单元格是隐藏的，则置高度为0            imageHeight += heightPoint;                    rowPixPos[i+1] = (int) (heightPoint * 96 / 72) + rowPixPos[i];         }         imageHeight = imageHeight * 96 / 72;        imageWidth = imageWidth * 115 / 100;         wb.close();         List
      
        grids = new ArrayList
       
        ();        for (int i = 0; i < rowSize; i++) {            for (int j = 0; j < colSize; j++) {                Grid grid = new Grid();                // 设置坐标和宽高                grid.setX(colPixPos[j]);                grid.setY(rowPixPos[i]);                grid.setWidth(colPixPos[j + 1] - colPixPos[j]);                grid.setHeight(rowPixPos[i + 1] - rowPixPos[i]);                grid.setRow(cells[i][j].getRow());                grid.setCol(cells[i][j].getCol());                grid.setShow(cells[i][j].isShow());                 // 判断是否为合并单元格                int[] isInMergedStatus = isInMerged(grid.getRow(), grid.getCol(), rangeAddress);                 if (isInMergedStatus[0] == 0 && isInMergedStatus[1] == 0) {                    // 此单元格是合并单元格，并且不是第一个单元格，需要跳过本次循环，不进行绘制                    continue;                } else if (isInMergedStatus[0] != -1 && isInMergedStatus[1] != -1) {                    // 此单元格是合并单元格，并且属于第一个单元格，则需要调整网格大小                                     int lastRowPos=isInMergedStatus[0]>rowSize-1?rowSize-1:isInMergedStatus[0];                    int lastColPos=isInMergedStatus[1]>colSize-1?colSize-1:isInMergedStatus[1];                                                          grid.setWidth(colPixPos[lastColPos + 1] - colPixPos[j]);                    grid.setHeight(rowPixPos[lastRowPos + 1] - rowPixPos[i]);                                                          }                 // 单元格背景颜色                CellStyle cs = cells[i][j].getCell().getCellStyle();                if (cs.getFillPattern() == CellStyle.SOLID_FOREGROUND)                    grid.setBgColor(cells[i][j].getCell().getCellStyle().getFillForegroundColorColor());                 // 设置字体                org.apache.poi.ss.usermodel.Font font = wb.getFontAt(cs.getFontIndex());                grid.setFont(font);                 // 设置字体前景色                if (font instanceof XSSFFont) {                    XSSFFont xf = (XSSFFont) font;                     grid.setFtColor(xf.getXSSFColor());                }                 // 设置文本                String strCell = "";                switch (cells[i][j].getCell().getCellType()) {                case HSSFCell.CELL_TYPE_NUMERIC:                                                           strCell = String.valueOf(cells[i][j].getCell().getNumericCellValue());                    break;                case HSSFCell.CELL_TYPE_STRING:                    strCell = cells[i][j].getCell().getStringCellValue();                    break;                case HSSFCell.CELL_TYPE_BOOLEAN:                    strCell = String.valueOf(cells[i][j].getCell().getBooleanCellValue());                    break;                case HSSFCell.CELL_TYPE_FORMULA:                                         try {                        strCell = String.valueOf(cells[i][j].getCell().getNumericCellValue());                    } catch (IllegalStateException e) {                        strCell = String.valueOf(cells[i][j].getCell().getRichStringCellValue());                    }                    break;                default:                    strCell = "";                }                                 if(cells[i][j].getCell().getCellStyle().getDataFormatString().contains("0.00%")){                    try{                        double dbCell=Double.valueOf(strCell);                        strCell=new DecimalFormat("#.00").format(dbCell*100)+"%";                    }catch(NumberFormatException e){}                                  }                                                 grid.setText(strCell.matches("\\w*\\.0") ? strCell.substring(0, strCell.length() - 2) : strCell);                 grids.add(grid);            }        }         BufferedImage image = new BufferedImage(imageWidth, imageHeight, BufferedImage.TYPE_INT_RGB);        Graphics2D g2d = image.createGraphics();        // 平滑字体        g2d.setRenderingHint(SunHints.KEY_ANTIALIASING, SunHints.VALUE_ANTIALIAS_OFF);        g2d.setRenderingHint(SunHints.KEY_TEXT_ANTIALIASING, SunHints.VALUE_TEXT_ANTIALIAS_DEFAULT);        g2d.setRenderingHint(SunHints.KEY_STROKE_CONTROL, SunHints.VALUE_STROKE_DEFAULT);        g2d.setRenderingHint(SunHints.KEY_TEXT_ANTIALIAS_LCD_CONTRAST, 140);        g2d.setRenderingHint(SunHints.KEY_FRACTIONALMETRICS, SunHints.VALUE_FRACTIONALMETRICS_OFF);        g2d.setRenderingHint(SunHints.KEY_RENDERING, SunHints.VALUE_RENDER_DEFAULT);         g2d.setColor(Color.white);        g2d.fillRect(0, 0, imageWidth, imageHeight);         // 绘制表格        for (Grid g : grids) {            if (!g.isShow())                continue;             // 绘制背景色            g2d.setColor(g.getBgColor() == null ? Color.white : g.getBgColor());            g2d.fillRect(g.getX(), g.getY(), g.getWidth(), g.getHeight());             // 绘制边框            g2d.setColor(Color.black);            g2d.setStroke(new BasicStroke(1));            g2d.drawRect(g.getX(), g.getY(), g.getWidth(), g.getHeight());             // 绘制文字,居中显示            g2d.setColor(g.getFtColor());            Font font = g.getFont();            FontMetrics fm = g2d.getFontMetrics(font);            int strWidth = fm.stringWidth(g.getText());// 获取将要绘制的文字宽度            g2d.setFont(font);            g2d.drawString(g.getText(),                    g.getX() + (g.getWidth() - strWidth) / 2,                    g.getY() + (g.getHeight() - font.getSize()) / 2 + font.getSize());        }         g2d.dispose();        ByteArrayOutputStream byteArrayOut = new ByteArrayOutputStream();        ImageIO.write(image, "png", new File("D:/temp/test.png"));        return byteArrayOut;    }    /**     * 判断Excel中的单元格是否为合并单元格     *     * @param row     * @param col     * @param rangeAddress     * @return 如果不是合并单元格返回{-1,-1},如果是合并单元格并且是一个单元格返回{lastRow,lastCol},     *         如果是合并单元格并且不是第一个格子返回{0,0}     */    private static int[] isInMerged(int row, int col, List
        
          rangeAddress) {        int[] isInMergedStatus = { -1, -1 };        for (CellRangeAddress cra : rangeAddress) {            if (row == cra.getFirstRow() && col == cra.getFirstColumn()) {                isInMergedStatus[0] = cra.getLastRow();                isInMergedStatus[1] = cra.getLastColumn();                return isInMergedStatus;            }            if (row >= cra.getFirstRow() && row <= cra.getLastRow()) {                if (col >= cra.getFirstColumn() && col <= cra.getLastColumn()) {                    isInMergedStatus[0] = 0;                    isInMergedStatus[1] = 0;                    return isInMergedStatus;                }            }        }        return isInMergedStatus;    }}
        
       
      
     

package ibp.common.report;import java.awt.Color;import org.apache.poi.ss.usermodel.Cell;  public class UserCell implements Comparable
     
      {    private Cell cell;    private int row;    private int col;    private boolean show;    private String text="";    private Color   color=null;          public Cell getCell() {        return cell;    }    public void setCell(Cell cell) {        this.cell = cell;    }    public int getRow() {        return row;    }    public void setRow(int row) {        this.row = row;    }    public int getCol() {        return col;    }    public void setCol(int col) {        this.col = col;    }    public boolean isShow() {        return show;    }    public void setShow(boolean show) {        this.show = show;    }    public String getText() {        return text;    }    public void setText(String text) {        this.text = text;    }          public Color getColor() {        return color;    }    public void setColor(Color color) {        this.color = color;    }    @Override    public int compareTo(UserCell uc) {        try{            double meDouble=Double.parseDouble(this.getText().replaceAll("%", ""));            double heDouble=Double.parseDouble(uc.getText().replaceAll("%", ""));            if(meDouble
      
       heDouble)                return  1;        }catch(Exception e){}                  return  0;    }}
      
     

package ibp.common.report;import java.awt.Color;import java.awt.Font;  import org.apache.poi.hssf.util.HSSFColor;import org.apache.poi.xssf.usermodel.XSSFColor;  public class Grid {    private boolean show;    private int row;    //对应Excel中的row,也可以理解为cells[i][j]的i    private int col;    //对应Excel中的col,也可以理解为cells[i][j]的j    private int x;  //x坐标    private int y;  //y坐标    private int width;    private int height;    private String text;    private java.awt.Font font=new Font("微软雅黑",Font.PLAIN, 12);    private java.awt.Color bgColor=null;    private java.awt.Color ftColor=null;    public int getRow() {        return row;    }    public void setRow(int row) {        this.row = row;    }    public int getCol() {        return col;    }    public void setCol(int col) {        this.col = col;    }    public int getX() {        return x;    }    public void setX(int x) {        this.x = x;    }    public int getY() {        return y;    }    public void setY(int y) {        this.y = y;    }    public boolean isShow() {        return show;    }    public void setShow(boolean show) {        this.show = show;    }    public int getWidth() {        return width;    }    public void setWidth(int width) {        this.width = width;    }    public int getHeight() {        return height;    }    public void setHeight(int height) {        this.height = height;    }    public String getText() {        return text;    }    public void setText(String text) {        this.text = text;    }    public Color getBgColor() {        return bgColor;    }          /**     * 将poi.ss.usermodel.Color 转换成  java.awt.Color     * @param color     */    public void setBgColor(org.apache.poi.ss.usermodel.Color color) {        this.bgColor=poiColor2awtColor(color);    }          public void setBgColor(java.awt.Color color){        this.bgColor=color;    }          public Color getFtColor() {        return ftColor;    }    public void setFtColor(org.apache.poi.ss.usermodel.Color color) {        this.ftColor = poiColor2awtColor(color);    }          public Font getFont() {        return font;    }    public void setFont(org.apache.poi.ss.usermodel.Font font) {        if(font!=null){            this.font=new java.awt.Font(font.getFontName(),Font.BOLD,font.getFontHeight()/ 20+  2);                   }    }                private java.awt.Color poiColor2awtColor(org.apache.poi.ss.usermodel.Color color){             java.awt.Color awtColor=null;        if(color instanceof XSSFColor){     //.xlsx            XSSFColor xc=(XSSFColor) color;            String rgbHex=xc.getARGBHex();            if(rgbHex!=null){                awtColor=new Color(Integer.parseInt(rgbHex.substring(  2),  16));            }        }else if(color instanceof HSSFColor){   //.xls            HSSFColor hc=(HSSFColor) color;            short[] s=hc.getTriplet();            if(s!=null){                awtColor=new Color(s[  0],s[  1],s[  2]);            }        }        return awtColor;    }}