Spring – 在jsp文件上显示图像
我的模型商店图像用文件名(作为String)和数据(作为字节数组)描述。 我使用Hibernate,这是我的模型:
@Entity public class Image { private Long id; private String name; private byte[] data; @Id @GeneratedValue @Column(name = "IMAGE_ID") public Long getId() { return id; } public void setId(Long id) { this.id = id; } @Column(nullable = false, length = 100) public String getName() { return name; } public void setName(String name) { this.name = name; } @Lob @Column(nullable = false) public byte[] getData() { return data; } public void setData(byte[] data) { this.data = data; } }
但我想在网站上显示我存储的图像,如:
我怎么能这样做?
我应该编写服务于图像请求的控制器吗?
任何代码示例?
UPDATE
/WEB-INF/configs/tiles.xml
你不能这样做。 您的图片必须通过普通url以某种方式曝光。 在Spring MVC中创建一个控制器,在特定的URL下返回一个图像(原始数据):
@RequestMapping(value = "/imageController/{imageId}") @ResponseBody public byte[] helloWorld(@PathVariable long imageId) { Image image = //obtain Image instance by id somehow from DAO/Hibernate return image.getData(); }
现在在JSP页面中使用。 这是HTTP / HTML的工作方式:
在3.1之前的Spring MVC中,您可能需要在控制器端进行更多编码。 但原则是一样的。
File file = new File("home/user/test.jpg"); FileInputStream fis=new FileInputStream(file); ByteArrayOutputStream bos=new ByteArrayOutputStream(); int b; byte[] buffer = new byte[1024]; while((b=fis.read(buffer))!=-1){ bos.write(buffer,0,b); } byte[] fileBytes=bos.toByteArray(); fis.close(); bos.close(); byte[] encoded=Base64.encodeBase64(fileBytes); String encodedString = new String(encoded); ModelMap map = new ModelMap(); map.put("image", encodedString);
现在在JSP页面中使用它
`
您可能需要查看此post 。 我有类似你的问题,解决方案是将字节数组转换为字符串并在img标签中设置,如下所示,
几天前我正在寻找正确的答案,所以我会为我写好的:
我的图片已保存在数据库中:
@Entity @Table(name="PRODUCT") public class Product { @Lob @Column(name="IMG") private byte[] img; // setters getters etc }
现在在我的class级中,例如ShowPicture,我必须阅读它:
String encodedImage = Base64.encode(product.getImg()); //setters and getters encodedImage
然后是我的jsp页面:
' alt="my image" />
就那么简单 ! 🙂
byte[] img = yourImgEntity.getData(); response.setContentType("image/*"); response.setHeader(HttpHeaders.CACHE_CONTROL, "no-cache"); //spring-core's FileCopyUtils FileCopyUtils.copy(img, response.getOutputStream()); // or just use codes below instead of FileCopyUtils //response.getOutputStream().write(img); //response.getOutputStream().flush(); //response.getOutputStream().close();
也许已经很晚了,但在这里我留下了一些能为我服务的东西,也许有人可以提供帮助。
我也在使用Spring MVC和Hibernate
在模型(实体类)中创建String类型的变量,以使用Base64将byte类型转换为String。
我这样做是为了一张我拥有各自国旗的国家的表格,我想要的是在所有国家的一个表格中列出它的旗帜。
型号(实体)
import com.sun.org.apache.xerces.internal.impl.dv.util.Base64; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax.persistence.Table; import javax.persistence.Transient; @Entity @Table(name = "country") public class Country implements java.io.Serializable { private int id; private String name; private byte[] flag; private String base64; //Variable to store the conversion of a data byte type to String @Transient //Annotation so it does not persist in the database public String getBase64() { //Convert the data type byte to String, store it in the variable and return it return this.base64 = Base64.encode(this.flag); } public void setBase64(String base64) { this.base64 = base64; } public Country() { } public Country(int id, String name, byte[] flag, String base64) { this.id = id; this.name = name; this.flag = this.flag this.base64 = this.base64; } @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name = "id", unique = true, nullable = false) public int getId() { return this.id; } public void setId(int id) { this.id = id; } @Column(name = "name") public String getName() { return this.name; } public void setName(String name) { this.name = name; } @Column(name = "flag") public byte[] getFlag() { return this.flag; } public void setFlag(byte[] flag) { this.flag = flag; } }
Repository – Implements是一个接口 – AbstractDao是一个类Abstract import org.springframework.stereotype.Repository; import application.model.Country; import application.repository.dao.AbstractDao; import application.repository.dao.CountryDao; import org.hibernate.Criteria;
@Repository("countryDao") public class CountryDaoImpl extends AbstractDao implements CountryDao { @Override @SuppressWarnings("unchecked") public List listCountries() { Criteria criteria = createEntityCriteria(); //Country.class criteria.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY); List listCountries = criteria.list(); return listCountries; } }
Service – implements是一个接口
import application.model.Country; import application.repository.dao.CountryDao; import application.service.dao.CountryService; import java.util.List; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Service; import org.springframework.transaction.annotation.Transactional; @Service("countryService") public class CountryServiceImpl implements CountryService { @Autowired private CountryDao countryDao; @Override @Transactional(readOnly = true) public List listCountries() { return countryDao.listCountries(); } }
调节器
import application.model.Country; import application.service.dao.CountryService; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.RequestMapping; @Controller @RequestMapping(value = "/countries") public class CountryController { @Autowired private CountryService countryService; @RequestMapping(value = "/list", method = RequestMethod.GET) public String ListCountries(Model model) { model.addAttribute("listcont", countryService.listCountry()); return "countries/countries"; //view } }
查看 – countries / countries.jsp
<%@page contentType="text/html" pageEncoding="UTF-8"%> <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> List Countries
Name Flag ${country.name}