JavaWeb实现图片异步上传，在前台展示，并以二进制保存到数据库

通过（ajaxFileupload.js)提供的ajaxFileUpload方法，异步上传图片，在后台获取并转二进制先存入session中，成功后返回图片的id到ajax，并通过jQuery改变 img src的地址请求该图片的二进制资源。

二次上传会覆盖前一次保存在session中的对象，确定保存后会把session中的对象保存到出数据库中。就可以通过id来请求数据库中的图片二进制资源。

前台HTML代码

<%-- 图片展示 src为默认图片资源--%
<img id="upload" class="pointer img-rounded" alt="点击上传" src="../../../resources/img/upload.jpg" width="100%">
<%-- 图片上传 -->
<input id="upfile" style="display: none" type="file" name="upfile">

JavaScript

 /**
         * 上传图片
         */
         $("#upload").on('click',function(){
             $("#upfile").click();
         });

        $("#upfile").on("change",upfile);

        function upfile(){
            $.ajaxFileUpload({
                secureuri:false,
                url:"upImg.aj",
                dataType:"json",
                //fileElementId是img标签的id
                fileElementId:'upfile',
                success:function(data){
                    //上传成功后改变<img>标签的src地址，id参数其实不需要，主要是为了刷新img的图片资源。
                    $("#upload").attr("src","getCurImg.aj?id="+data.message);
                    //重新绑定事件，防止二次上传时失效
                    $("#upfile").on("change",upfile);
                }
            });
        }

后台Controller

/**
 * 上传图片到session
 * @param response
 * @param request
     */
@RequestMapping(value = "/upImg.aj", method = RequestMethod.POST)
public void upImgSession(HttpServletResponse response, HttpServletRequest request, HttpSession httpSession) {

//获取图片
MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) request;
//根据前台name名称得到上传的文件
MultipartFile img = multipartRequest.getFile("upfile");
//定义一个数组，用于保存可上传的文件类型
List fileTypes = new ArrayList();
fileTypes.add("jpg");
fileTypes.add("jpeg");
fileTypes.add("bmp");
fileTypes.add("png");
String fileName = img.getOriginalFilename();
Long id=null;
ResultModel rm=null;
if(!(fileName==null ||"".equals(fileName))){
String extensionName = fileName.substring(fileName.lastIndexOf(".")+1);
if(fileTypes.contains(extensionName)){
//扩展名合法
try{
id = System.currentTimeMillis();
byte[] content=img.getBytes();
String extension="image/"+extensionName;
WjbDO wjbDO = new WjbDO(content,extension,id);
httpSession.setAttribute("curImg",wjbDO);
}catch (IOException e){
e.printStackTrace();
}
rm=new ResultModel(id.toString(), 1);
}
}else{
rm=new ResultModel("上传失败", 0);
}

ResponseBuilder rb = new ResponseBuilder();
try {
rb.writeJsonResponse(response,rm);

}catch (IOException e){
log.info("IOException",e);
}
}
/**
 * 从session请求图片二进制流
 * @param response
 * @param request
 */
@RequestMapping(value = "/getCurImg.aj", method = RequestMethod.GET)
public String getCurImg(HttpServletResponse response,HttpServletRequest request,HttpSession httpSession) {


WjbDO wjbDO = (WjbDO)httpSession.getAttribute("curImg");
//设置文件格式
response.setContentType(wjbDO.getExtension());
try{
OutputStream out = response.getOutputStream();
out.write(wjbDO.getContent());
out.close();
}catch (IOException e){
log.error("输出图片流失败",e);
}
return null;


}
/**
 * 确认保存后提交图片到数据库
 * @param response
     */
@RequestMapping(value = "/zcdj.aj", method = RequestMethod.POST)
public void zcdjSave(HttpServletResponse response, HttpServletRequest request,HttpSession httpSession) {
//保存上传图片
WjbDO wjbDO = (WjbDO)httpSession.getAttribute("curImg");
if (wjbDO!=null){
zcModel.setImg(wjbDO.getId());
wjService.saveWj(wjbDO);
}
}

WjService.java

public interface WjService {
    boolean saveWj(WjbDO wjbDO);

    WjbDO findById(Long id);

    boolean update(WjbDO wjbDO);

    boolean del(Long id);
}

WjServiceImpl.java

public class WjServiceImpl implements WjService {

    WjbDao wjbDao;

    @Transactional
    public boolean saveWj(WjbDO wjbDO){
        return wjbDao.save(wjbDO);
    }

    public WjbDO findById(Long id){
         return wjbDao.findById(id);
    }

    @Transactional
    public boolean update(WjbDO wjbDO){
        wjbDao.attachDirty(wjbDO);
        return true;
    }

    @Transactional
    public boolean del(Long id){
        WjbDO wjbDO = wjbDao.findById(id);
        if (wjbDO!=null){
            wjbDao.delete(wjbDO);
            return true;
        }
        return false;
    }

    public WjbDao getWjbDao() {
        return wjbDao;
    }

    public void setWjbDao(WjbDao wjbDao) {
        this.wjbDao = wjbDao;
    }
}

WjbDao.java

public class WjbDao extends HibernateDaoSupport{
    private  static  final Logger log = LoggerFactory.getLogger(WjbDao.class);

    protected  void initDao(){
        // do nothing
    }

    public boolean save(WjbDO transientInstance){
        log.debug("saving WjbDO instance");
        try{
            Serializable serializable = getHibernateTemplate().save(transientInstance);
            if (serializable != null){
                log.debug("save successful");
                return true;
            }
        }catch(RuntimeException re){
            log.error("save failed",re);
            throw re;
        }
        return false;
    }
    public void delete(WjbDO persistentInstance) {
        log.debug("deleting WjbDO instance");
        try {
            getHibernateTemplate().delete(persistentInstance);
            log.debug("delete successful");
        } catch (RuntimeException re) {
            log.error("delete failed", re);
            throw re;
        }
        // 刷新Session
//        getSession().flush();
    }
    public WjbDO findById(Long id) {
        log.debug("getting WjbDO instance with id: " + id);
        try {
            WjbDO instance = (WjbDO) getHibernateTemplate().get(
                    "nju.software.fams.data.daoobject.WjbDO", id);
            return instance;
        } catch (RuntimeException re) {
            log.error("get failed", re);
            throw re;
        }
    }
    public void attachDirty(WjbDO instance) {
        log.debug("attaching dirty WjbDO instance");
        try {
            getHibernateTemplate().saveOrUpdate(instance);
            log.debug("attach successful");
        } catch (RuntimeException re) {
            log.error("attach failed", re);
            throw re;
        }
    }

    public void attachClean(WjbDO instance) {
        log.debug("attaching clean WjbDO instance");
        try {
            getHibernateTemplate().lock(instance, LockMode.NONE);
            log.debug("attach successful");
        } catch (RuntimeException re) {
            log.error("attach failed", re);
            throw re;
        }
    }

    public void delById(long id){
        log.debug("attaching clean ZcDO instance");
        Session session = getSessionFactory().getCurrentSession();
        session.createQuery("delete from WjbDO where id=?").setParameter(0,id).executeUpdate();
    }
}

WjbDO.java

@Entity
@Table(name = "FAMS_WJB",schema = "FixAssetMS")
public class WjbDO {

    private Long id;

    private byte[] content;
    /**
     * 扩展名
     */
    private String extension;

    public WjbDO(byte[] content, String extension, Long id) {
        this.content = content;
        this.extension = extension;
        this.id = id;
    }

    public WjbDO() {
    }

    @Id
    @Column(name = "ID_WJ")
    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    @Column(name = "CONTENT")
    public byte[] getContent() {
        return content;
    }

    public void setContent(byte[] content) {
        this.content = content;
    }

    @Column(name = "EXTENSION")
    public String getExtension() {
        return extension;
    }

    public void setExtension(String extension) {
        this.extension = extension;
    }

    @Override
    public String toString() {
        return "WjbDO{" +
                "extension='" + extension + '\'' +
                ", id=" + id +
                '}';
    }
}

秒客网

JavaWeb实现图片异步上传，在前台展示，并以二进制保存到数据库

相关文章