保存MySQL之前获取自动增量ID

Question

我有一个应用程序，用户必须将信息保存到DataBase和图像到文件系统目录，并保存数据库中的图像路径。我的问题是如何从数据库表中获取ID（自动增量）以在数据库中创建路径。例子：car1200.jpeg（car：图像名称，1200：用户的Id）。 我的代码： 控制器：

@RequestMapping(value="/save",method=RequestMethod.POST)
    public String add ( @RequestParam("prix") Long prix, 
            RequestParam("adresse") String ville,
            @RequestParam("categorie") String categorie,
            @RequestParam("photos") MultipartFile file,
            ) throws FileNotFoundException


 {

   String chemin=null;
   if (!file.isEmpty())
     {
      try {
       String orgName = file.getOriginalFilename();
       // this line to retreive just file name 
       String 
       name=orgName.substring(orgName.lastIndexOf("\\")+1,orgName.length());
       chemin="e:\\images\\"+name;// here I want to add ID of the user ,I 
       //don t know how to get since it is auto increment 
       File file1=new File(chemin);
       file.transferTo(file1);
         } catch (IOException e) {
                                    e.printStackTrace();
                                  }

    }
    annonce.setImage(chemin);
    annonce.setTitre(prix);
    annonce.setCorps(ville);
    annonce.setPrix(cetegorie)
    annoncedao.save(annonce);
    return "SuccessAddAnnonce";
}

Annonce班：

package com.eBenamar.Entities;
import java.io.Serializable;
import java.sql.Blob;
import java.util.Date;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.Lob;
import javax.persistence.OneToOne;
import org.hibernate.annotations.Cascade;
import org.hibernate.validator.constraints.NotEmpty;

/**
 * @author user
 *
 */
@Entity
public class Annonce implements Serializable {
    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    @Id @GeneratedValue
    Integer id;
    @NotEmpty
    String titre;
    Long prix;
    @Column(length=10000000)
    byte [] photos;
    public byte[] getPhotos() {
        return photos;
       }
    String ville;
    String categorie;
    @Lob
    @Column(length=10000000)
    byte []   photos;

    public Annonce() {
        super();
        // TODO Auto-generated constructor stub
    }
    public Annonce( String ville, Long prix, String categorie,
            byte[] photos) {
        super();
        this.ville= ville;
        this.prix = prix;
        this.categorie = categorie;
        this.photos = photos;

    }



    public Annonce( String categorie, Long prix, String ville, byte[] photos) {
        super();
        this.ville= ville;
        this.categorie = categorie;
        this.prix = prix;
        this.photos = photos;
    }

    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public String getVille() {
        return ville;
    }
    public void setTVille(String ville) {
        this.ville = ville;
    }
    public String getCategorie() {
        return categorie;
    }
    public void setCategorie(String categorie) {
        this.categorie= categorie;
    }
    public Long getPrix() {
        return prix;
    }
    public void setPrix(Long prix) {
        this.prix = prix;
    }
    public byte[] getPhotos() {
        return photos;
    }
    public void setPhotos(byte[] photos) {
        this.photos = photos;
    }

}

我想获取数据库中保存的最后一个ID（自动增量）。