好吧，尤尼托，让我看看。。。已更改的account.java（模型）：

@Entity
@Table(name = "accounts")
public class Account {
    @Id
    @GeneratedValue(strategy = GenerationType.AUTO)
    private long id;
    private boolean ifBasicAccount;
    private String accTitle;
    private String accFirstName;
    private String accLastName;
    private String accBirthdate;
    private String accPhoneNumber;
    private String accEducation;
    private String accExperience;
    private String accAbilities;
    private String accInterests;
    private String accProjects;
    private String accDescription;
    @Lob
    private byte[] accPicture;
    private String stringPhoto;
    @ManyToOne
    private User user;
    public Account() {
    }
    public long getId() {
        return id;
    }
    public void setId(long id) {
        this.id = id;
    }
    public String getAccTitle() {
        return accTitle;
    }
    public void setAccTitle(String accTitle) {
        this.accTitle = accTitle;
    }
    public String getAccFirstName() {
        return accFirstName;
    }
    public void setAccFirstName(String accFirstName) {
        this.accFirstName = accFirstName;
    }
    public String getAccLastName() {
        return accLastName;
    }
    public void setAccLastName(String accLastName) {
        this.accLastName = accLastName;
    }
    public String getAccBirthdate() {
        return accBirthdate;
    }
    public void setAccBirthdate(String accBirthdate) {
        this.accBirthdate = accBirthdate;
    }
    public String getAccPhoneNumber() {
        return accPhoneNumber;
    }
    public void setAccPhoneNumber(String accPhoneNumber) {
        this.accPhoneNumber = accPhoneNumber;
    }
    public String getAccEducation() {
        return accEducation;
    }
    public void setAccEducation(String accEducation) {
        this.accEducation = accEducation;
    }
    public String getAccExperience() {
        return accExperience;
    }
    public void setAccExperience(String accExperience) {
        this.accExperience = accExperience;
    }
    public String getAccAbilities() {
        return accAbilities;
    }
    public void setAccAbilities(String accAbilities) {
        this.accAbilities = accAbilities;
    }
    public String getAccInterests() {
        return accInterests;
    }
    public void setAccInterests(String accInterests) {
        this.accInterests = accInterests;
    }
    public String getAccProjects() {
        return accProjects;
    }
    public void setAccProjects(String accProjects) {
        this.accProjects = accProjects;
    }
    public String getAccDescription() {
        return accDescription;
    }
    public void setAccDescription(String accDescription) {
        this.accDescription = accDescription;
    }
    public byte[] getAccPicture() {
        return accPicture;
    }
    public void setAccPicture(byte[] accPicture) {
        this.accPicture = accPicture;
    }
    public String getStringPhoto() {
        return convertBinImageToString(accPicture);
    }
    public void setStringPhoto(String stringPhoto) {
        this.stringPhoto = stringPhoto;
    }
    public User getUser() {
        return user;
    }
    public void setUser(User user) {
        this.user = user;
    }
    public boolean isIfBasicAccount() {
        return ifBasicAccount;
    }
    public void setIfBasicAccount(boolean ifBasicAccount) {
        this.ifBasicAccount = ifBasicAccount;
    }
    public static String convertBinImageToString(byte[] accPicture) {
        if(accPicture!=null && accPicture.length>0) {
            return Base64.getEncoder().encodeToString(accPicture);
        }
        else
            return "";
    }
}

我有两个控制器（一个仅用于显示图像-我不太确定这是件好事，因为我有两个相同的请求Map）。因此，请参见更改的imagecontroller：

@Controller
@RequestMapping("/admin/user")
public class ImageController {
    @Autowired
    AccountRepository accountRepository;
    @RequestMapping(value = "/accounts", method = RequestMethod.GET)
    public void showImage(@RequestParam("id") long id, Model model) {
        Account account = accountRepository.findById(id);
        String photoencodeBase64 = account.getStringPhoto();
        model.addAttribute("accPicture", photoencodeBase64);
    }
}

和.jsp来显示图像：

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
    <%@ taglib prefix = "c" uri = "http://java.sun.com/jsp/jstl/core" %>
    <%@ taglib prefix = "fmt" uri = "http://java.sun.com/jsp/jstl/fmt" %>
     <%@ page isELIgnored="false" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%@ include file="/WEB-INF/parts/header.jsp" %>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Insert title here</title>
</head>
<body>
<div align="center">
<table class="table table-striped">
<h1>Accounts:</h1>
<c:forEach items="${accounts}" var="account" begin="0" varStatus="theCount">
    <tr>
        <td>${theCount.index+1}</td>
        <td><b>Title: </b>${account.accTitle}</td>
        <td><b>Description: </b>${account.accDescription}</td>
        <td><b>Image: </b><img id="photo" src="data:image/png;base64,${account.accPicture}" /></td>
        <td><a style="width: 180px;height: 20px;" href="./edit/${account.id}" class="badge badge-primary">Show/Edit</a></td>
        <td><a style="width: 180px;height: 20px;" href="./delete/${account.id}" class="badge badge-danger">Delete</a></td>
    </tr>
</c:forEach>
</table>
     <a href="<c:url value="/addAccount"/>">Add Account</a>
</body>
</html>

当我添加新帐户->写标题，名字等，从我的浏览器显示的文件中添加图像时，会发生什么 HTTP Status 400 - The request sent by the client was syntactically incorrect. ->我需要查看所有用户帐户。在sts控制台里什么也没发生。在mysql中也是如此。

为什么不使用spring内容jpa呢？这可以提供存储服务和rest端点，用于管理与jpa实体关联的内容。
pom.xml文件

<!-- Java API -->
   <dependency>
      <groupId>com.github.paulcwarren</groupId>
      <artifactId>spring-content-jpa</artifactId>
      <version>0.1.0</version>
   </dependency>
   <!-- REST API -->
   <dependency>
      <groupId>com.github.paulcwarren</groupId>
      <artifactId>spring-content-rest</artifactId>
      <version>0.1.0</version>
   </dependency>

配置

@Configuration
@EnableJpaStores
@Import("org.springframework.content.rest.config.RestConfiguration.class")
public class MysqlConfig {
    // schema management
    // 
    @Value("/org/springframework/content/jpa/schema-drop-mysql.sql")
    private Resource dropRepositoryTables;
    @Value("/org/springframework/content/jpa/schema-mysql.sql")
    private Resource dataRepositorySchema;
    @Bean
    DataSourceInitializer datasourceInitializer() {
        ResourceDatabasePopulator databasePopulator =
                new ResourceDatabasePopulator();
        databasePopulator.addScript(dropReopsitoryTables);
        databasePopulator.addScript(dataReopsitorySchema);
        databasePopulator.setIgnoreFailedDrops(true);
        DataSourceInitializer initializer = new DataSourceInitializer();
        initializer.setDataSource(dataSource());
        initializer.setDatabasePopulator(databasePopulator);
        return initializer;
    }
}

要关联内容，请向帐户实体添加spring内容注解。
帐户.java

@Entity
public class Account {
   // replace @Lob field with
   @ContentId
   private String contentId;
   @ContentLength
   private long contentLength = 0L;
   // if you have rest endpoints
   @MimeType
   private String mimeType = "text/plain";

创建“商店”：
accountimagesstore.java文件

@StoreRestResource(path="accountImages)
public interface AccountImagesStore extends ContentStore<Account, String> {
}

这就是创建rest端点所需的全部@ /accountImages . 当您的应用程序启动时，spring内容将查看您的依赖项（查看spring内容jpa/rest），查看您的 AccountImagesStore 接口并为jpa注入该接口的实现。它还将注入 @Controller 将http请求转发给该实现。这就省得你自己去实现我认为你所追求的。
所以。。。 curl -X POST /accountImages/{account-id} 对于多部分/表单，数据请求将图像存储在数据库中，并将其与id为的帐户实体相关联 account-id . curl /accountImages/{account-id} 将再次获取它等等…支持完全积垢。
因此，您只需在jsp中显示一个图像标记：
这里有一些入门指南。参考指南在这里。这里有一个教程视频。编码位大约从1/2开始。
hth公司

<img id="photo" src="data:image/png;base64,${PHOTOYOUNEED}" />

在负责将图像发送到html的控制器中：

(...)
    String photoencodeBase64 = modelX.getStringPhoto();
    modelAndView.addObject("PHOTOYOUNEED", photoencodeBase64 );

我还在模型中使用此方法将byte[]转换为base64中的字符串：

public static String convertBinImageToString(byte[] binImage) {
    if(binImage!=null && binImage.length>0) {
        return Base64.getEncoder().encodeToString(binImage);
    }
    else
        return "";
}

我在模型内部的getstringphoto（）getter中调用它。