在业务中有需要用户信息确认时候去进行电子签名，在实现电子签名存证时候，可以在前端生成图片也可以在后端生成签名存证图片，这里实现一下关于后端Java实现的方法，并总结成工具类，方便之后调用。
工具类方法一
java
import com.sun.image.codec.jpeg.JPEGCodec;
import com.sun.image.codec.jpeg.JPEGImageEncoder;
import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;
/**
* @ClassName JsonToPicture
* @Description 根据描述生成对应的图片
* @Version 1.0
*/
public class Main {
public static void createImage(String fileLocation, BufferedImage image) {
try {
FileOutputStream fos = new FileOutputStream(fileLocation);
BufferedOutputStream bos = new BufferedOutputStream(fos);
JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(bos);
encoder.encode(image);
bos.close();
fos.close();
} catch (Exception e) {
e.printStackTrace();
}
}
public static void graphicsGeneration(String path, Map<String, String> list) throws IOException {
int imageWidth = 500;// 图片的宽度
int imageHeight = 500;// 图片的高度
BufferedImage image = new BufferedImage(imageWidth, imageHeight, BufferedImage.TYPE_INT_RGB);
Graphics graphics = image.getGraphics();
graphics.setColor(Color.white);
graphics.fillRect(0, 0, imageWidth, imageHeight);
graphics.setColor(Color.BLACK);
int high = 30;
int wigth = 0;
graphics.setFont(new Font("宋体", Font.BOLD, 30));
graphics.drawString("绩效确认单", 200, high);
graphics.setFont(new Font("宋体", Font.BOLD, 20));
high += 10;
graphics.drawLine(0, high, 550, high);
// for(Map<String, String> rowMap : list){
// high += 50;
// wigth = 40;
for (Map.Entry<String, String> entry : list.entrySet()) {
high += 50;
wigth = 40;
String name = entry.getKey() + "：" + entry.getValue();
if ("title".equals(entry.getKey())) {
high += 30;
graphics.setFont(new Font("黑体", Font.BOLD, 20));
graphics.drawString(entry.getValue(), wigth, high);
graphics.setFont(new Font("宋体", Font.BOLD, 20));
} else {
graphics.drawString(name, wigth, high);
graphics.drawImage(ImageIO.read(new File("D:\\upload\\background.jpg")), wigth, high, null);
wigth += 160;
}
}
// }
createImage(path, image);
}
/**
* 图片名生成
**/
public static String genImageName() {
//取当前时间的长整形值包含毫秒
long millis = System.currentTimeMillis();
//加上三位随机数
Random random = new Random();
int end3 = random.nextInt(999);
//如果不足三位前面补0
String str = millis + String.format("%03d", end3);
return str;
}
public static void main(String[] args) throws IOException {
// ArrayList<Map> list = new ArrayList<Map>();
// for (int i = 0; i < 8; i++) {
// Map<String, String> mapTitle = new HashMap<String, String>();
// mapTitle.put("单价/克", "20.0");
// mapTitle.put("克数", "1");
// mapTitle.put("名称", "柴胡");
// list.add(mapTitle);
// }
Map list = new HashMap();
for (int i = 0; i < 8; i++) {
list.put("加减分" + i, "2");
list.put("工作态度" + i, "1");
list.put("绩效系数" + i, "3");
}
String path = "d:/upload";
File newFileDir = new File(path);
//如果不存在 则创建
if (!newFileDir.exists()) {
newFileDir.mkdirs();
}
graphicsGeneration(path + "/" + genImageName() + ".jpg", list);
System.out.println("完成");
}
}这个方法需要提前准备一个background背景图片，然后的逻辑是根据前端获取到的数据（当然此处是自己模拟了一些假数据）写在这个图片上，最终将写好数据的图片生成在指定的地方。
工具类方法二
方法二与方法一类似，不过是采用创建对象的方式，获取数据，细节上都大同小异
java
public class ImgBean {
private Integer month ;
private Integer year ;
private String name;
private String degree;
private Integer attitude;
private Integer duty;
private String pMPoints;
private Float jxPoints;
private boolean checkStatus;
private Integer coefficient;
public Integer getCoefficient() {
return coefficient;
}
public void setCoefficient(Integer coefficient) {
this.coefficient = coefficient;
}
public Integer getMonth() {
return month;
}
public void setMonth(Integer month) {
this.month = month;
}
public Integer getYear() {
return year;
}
public void setYear(Integer year) {
this.year = year;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getDegree() {
return degree;
}
public void setDegree(String degree) {
this.degree = degree;
}
public Integer getAttitude() {
return attitude;
}
public void setAttitude(Integer attitude) {
this.attitude = attitude;
}
public Integer getDuty() {
return duty;
}
public void setDuty(Integer duty) {
this.duty = duty;
}
public String getpMPoints() {
return pMPoints;
}
public void setpMPoints(String pMPoints) {
this.pMPoints = pMPoints;
}
public Float getJxPoints() {
return jxPoints;
}
public void setJxPoints(Float jxPoints) {
this.jxPoints = jxPoints;
}
public boolean isCheckStatus() {
return checkStatus;
}
public void setCheckStatus(boolean checkStatus) {
this.checkStatus = checkStatus;
}
}首先，根据表上要创建的内容，创建对应的对象和属性
java
import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.image.BufferedImage;
import java.io.File;
/**
* 1、month：Integer月
* 2、year：Integer年
* 3、name:String姓名
* 4、degree：String完成度
* 5、attitude:Integer工作态度
* 6、duty:Integer管理责任
* 7、pMPoints:String加减分
* 8、jxPoints:Float 一位小数；绩效得分
* 9、checkStatus：boolean；是否确认
* 10、coefficient：绩效系数
*/
public class ImgToBeanUtils {
public static String overlapImage(
String backgroundPath, ImgBean bean, String outPutPath){
try {
String name = "姓名 : ";
String degree = "完成度 :";
String duty = "管理责任 ：";
String pMPoints = "加减分 ：";
String month = "月 ：";
String year = "年 ：";
String attitude = "工作态度 ：";
String jxPoints= "绩效得分 ：";
String coefficient= "绩效系数 ：";
String checkStatus = "是否确认 ：";
String message01 = String.valueOf(bean.getYear());//年
String message1 = year.concat(message01);
String message02 = String.valueOf(bean.getMonth()) ;//月
String message2 = month.concat(message02);
String message3 = name + bean.getName();//姓名
String message4 = degree + bean.getDegree();//完成度
String message05 = String.valueOf(bean.getAttitude());//工作态度
String message5 = attitude.concat(message05);
String message06 = String.valueOf(bean.getDuty());//管理责任
String message6 = duty.concat(message06);
String message7 = pMPoints + bean.getpMPoints();//加减分
String message08 = String.valueOf(bean.getJxPoints());//绩效得分
String message8 = jxPoints.concat(message08);
String message09 = String.valueOf(bean.getCoefficient());//绩效系数
String message9 = coefficient.concat(message09);
String message010 = String.valueOf(bean.isCheckStatus());//是否确认
String message10 = checkStatus.concat(message010);
//设置图片大小
//BufferedImage background = resizeImage(618,1000, ImageIO.read(new File(这里是背景图片的路径！)));
BufferedImage background = resizeImage(1000,618, ImageIO.read(new File(backgroundPath)));
Graphics2D g = background.createGraphics();
g.setColor(Color.ORANGE);
g.setFont(new Font("微软雅黑",Font.BOLD,20));
String[] strs = {message1,message2,message3,message4,message5,message6,message7,message8,message9,message10};
int y = 190;
for (int i = 0; i < 9; i++) {
g.drawString(strs[i],430 ,y );
y= y+30;
}
g.dispose();
//ImageIO.write(background, jpg, new File(这里是一个输出图片的路径));
ImageIO.write(background, "jpg", new File(outPutPath));
}catch (Exception e){
e.printStackTrace();}
return null;
}
public static BufferedImage resizeImage(int x, int y, BufferedImage bfi){
BufferedImage bufferedImage = new BufferedImage(x, y, BufferedImage.TYPE_INT_RGB);
bufferedImage.getGraphics().drawImage(
bfi.getScaledInstance(x, y, Image.SCALE_SMOOTH), 0, 0, null);
return bufferedImage;
}
/**
* 图片覆盖（覆盖图压缩到width*height大小，覆盖到底图上）
* @param baseFilePath 底图
* @param coverFilePath 覆盖图
* @param x 起始x轴
* @param y 起始y轴
* @param width 覆盖宽度
* @param height 覆盖长度度
* @throws Exception
*/
public static BufferedImage coverImage(String baseFilePath, String coverFilePath, int x, int y, int width, int height) throws Exception{
File baseFile = new File(baseFilePath);//底图
BufferedImage buffImg = ImageIO.read(baseFile);
File coverFile = new File(coverFilePath); //覆盖层
BufferedImage coverImg = ImageIO.read(coverFile);
buffImg = coverImage(buffImg, coverImg, x, y, width, height);
return buffImg;
}
/**
* 图片覆盖（覆盖图压缩到width*height大小，覆盖到底图上）
* @param baseBufferedImage 底图
* @param coverBufferedImage 覆盖图
* @param x 起始x轴
* @param y 起始y轴
* @param width 覆盖宽度
* @param height 覆盖长度度
* @throws Exception
*/
public static BufferedImage coverImage(BufferedImage baseBufferedImage, BufferedImage coverBufferedImage, int x, int y, int width, int height) throws Exception{
// 创建Graphics2D对象，用在底图对象上绘图
Graphics2D g2d = baseBufferedImage.createGraphics();
if(x>= baseBufferedImage.getWidth()){
x = baseBufferedImage.getWidth()-width;
}
if(y>= baseBufferedImage.getHeight()){
y = baseBufferedImage.getHeight()-height;
}
// 绘制
g2d.drawImage(coverBufferedImage, x, y, width, height, null);
g2d.dispose();// 释放图形上下文使用的系统资源
return baseBufferedImage;
}
}
java
import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.File;
import static com.example.demo.test.ImgToBeanUtils.overlapImage;
public class Test {
public static void main(String[] args) throws Exception {
ImgBean bean = new ImgBean();
bean.setName("李");
bean.setDegree("456");
bean.setDuty(123);
bean.setCheckStatus(true);
bean.setJxPoints(3.5F);
bean.setAttitude(2440);
bean.setYear(2023);
bean.setpMPoints("789");
bean.setMonth(4);
bean.setCoefficient(2);
overlapImage("D:\\background.jpg",bean,"D:\\TextPicture.jpg");
File file = new File("D:\\signature.jpg");
if (null == file || 0 == file.length() || !file.exists()) {
System.out.println("文件为空！");
}
BufferedImage r = ImgToBeanUtils.coverImage("D:\\TextPicture.jpg", "D:\\signature.jpg", 400, 200, 200, 200);
ImageIO.write(r, "jpg", new File("d://result.jpg"));
}
}原理其实也就是将签名（例如：张三 ）和用户绩效确认数据两个图层进行覆盖，最终生成一个电子签名存证文件。
