Question

我在mysql数据库中有一个BLOB类型的图像，我想在jsp上显示图像。我正在使用Hibernate和Spring MVC。这是我的Model类：

@Repository
@Entity
@Table(name = "foto")
public class Image {

    @ManyToOne(fetch = FetchType.LAZY)
    @JoinColumn(name = "fk_id_users", nullable = false)
    private Users user;

    @Id
    @Column(name = "id_foto")
    @GeneratedValue(strategy = GenerationType.AUTO)
    private int id_foto;

    @Column(name = "tipo")
    private String tipo;

    @Column(name = "size")
    private String size;

    @Column(name = "nome")
    private String nome;

    @Column(name = "image")
    private byte[] image;

    //Getters and Setters

这是我的控制者：

@Controller
@SessionAttributes("UserSession")
public class LoginController {

    @Autowired
    private UsersService usersService;

    @RequestMapping(value = "loginUsers", method = RequestMethod.POST)
    public ModelAndView loginUsers(HttpServletRequest request,@RequestParam("username") String username,
            @RequestParam("password") String password) {

        Users user = usersService.loginUsers(username, password);

        if( user == null ) {
            ModelAndView MV = new ModelAndView("login");
            MV.addObject("erroreLogin", "username e/o password errati");
            return MV;
        } else if ( user.getAmministratore() == false ){
            request.getSession().setAttribute("UserSession",user);
            ModelAndView mav = new ModelAndView("homeUtente");
            mav.addObject("galleria", usersService.getAllFoto());
            return mav;
        } else {
            request.getSession().setAttribute("UserSession",user);
            ModelAndView mav = new ModelAndView("utenti");
            mav.addObject("lista", usersService.getAllUtenti());
            return mav;
        }
    }

    @RequestMapping(value = "logout", method = RequestMethod.GET)
    public ModelAndView logout(HttpServletRequest request) {
        request.getSession().invalidate(); //invalido i dati presenti in sessione
        return new ModelAndView("login");
    }

}

在我的jsp中，我使用它来显示图像列表中的图像，因为每个用户都有一个要显示的图库：

<img alt="Kangoo_image" src="data:image/jpeg;base64,${galleria.image}" />

当我试图在我的jsp中显示它时，它显示的是二进制文件，如[B @ 59e73b47。如何在jsp中显示图像？

Answer 1

要在JSP上显示图像而不存储到文件系统并链接到它，您必须对字节数组进行Base64编码。通过以下行轻松完成

byte[] encodeBase64 = Base64.encodeBase64(usersService.getAllFoto());
String base64Encoded = new String(encodeBase64, "UTF-8");
mav.addObject("galleria", usersService.getAllFoto());

IOUtils和Base64都来自org.apache.commonsEndFragment

Answer 2

这附加因为galleria.image返回一个byte []类型，并且在jsp的结果html上出现byte [] .toString（）值。完全是[B @ 59e73b47。

你应该使用类似的东西：

<img alt="Kangoo_image" src="data:image/jpeg;base64,new String(${galleria.image})" />

或

<img alt="Kangoo_image" src="/getImage/${galleria.id_foto}" />

并且在 getImage 控制器中就像这样

@Autowired
private HttpServletRequest request;

@RequestMapping("/getImage/*")
public void getImage(ModelMap model, HttpServletResponse response)
        throws IOException {

    requestUri = requestUri.substring((request.getContextPath() + "/getImage/")
            .length());

    Image image = DAO.findById(requestUri);

    String requestUri = request.getRequestURI();

    InputStream is = new ByteArrayInputStream(image.getImage());
    response.setContentType("image/jpeg");
    String name = image.getName() + ".jpeg";
    String attachment = "inline; filename=" + name;
    response.setHeader("content-Disposition", attachment);
    response.setContentLength((int) baos.toByteArray().length);
    IOUtils.copy(is, response.getOutputStream());
    response.flushBuffer();
    is.close();
}

Answer 3

 @Controller
 @SessionAttributes("UserSession")
 public class LoginController {

 @Autowired
 private UsersService usersService;

 @RequestMapping(value = "loginUsers", method = RequestMethod.POST)
 public ModelAndView loginUsers(HttpServletRequest request,@RequestParam("username")   String username,
        @RequestParam("password") String password) {

    Users user = usersService.loginUsers(username, password);

    if( user == null ) {
        ModelAndView MV = new ModelAndView("login");
        MV.addObject("erroreLogin", "username e/o password errati");
        return MV;
    } else if ( user.getAmministratore() == false ){
        request.getSession().setAttribute("UserSession",user);
        ModelAndView mav = new ModelAndView("homeUtente");
         byte[] encodeBase64 = Base64.encode(usersService.getAllFoto());
         String base64Encoded = new String(encodeBase64, "UTF-8");
          mav.addObject("userImage", base64Encoded )
        return mav;
    } else {
        request.getSession().setAttribute("UserSession",user);
        ModelAndView mav = new ModelAndView("utenti");
        mav.addObject("lista", usersService.getAllUtenti());
        return mav;
    }
 }

 @RequestMapping(value = "logout", method = RequestMethod.GET)
 public ModelAndView logout(HttpServletRequest request) {
    request.getSession().invalidate(); //invalido i dati presenti in sessione
    return new ModelAndView("login");
 }

}

并在jsp代码中使用此代码显示图像

     <img  src="data:image/jpeg;base64,${userImage}" />

使用spring mvc和hibernate在jsp上显示图像

3 个答案: