如何将零件转换为Blob，所以我可以将其存储在MySQL？ [英] How to convert Part to Blob, so I can store it in MySQL?

问题描述

如何将Part转换为Blob，这样我就可以将它存储在MySQL中？这是一个图像。
谢谢

我的表单

 < h ：form id =formenctype =multipart / form-data> 
< h：messages /> 
< h：panelGrid columns =2> 
< h：outputText value =File：/> 
< h：inputFile id =filevalue =＃{uploadPage.uploadedFile}/> 
< / h：panelGrid> 
< br />< br /> 
< h：commandButton value =上传文件action =＃{uploadPage.uploadFile}/> 
< / h：表格> 
  

我的bean

  @Named 
 @ViewScoped 
 public class UploadPage {
 private part uploadedFile; 
 $ b $ public void uploadFile（）{
} 
} 
  

byte [] 。这是在JPA进一步被注释为 @Lob 。所以，你的模型基本上需要像这样：

$ p $ @Entity
public class SomeEntity {

@Lob
私人字节[]图片;

// ...
}


用 Part ，你基本上需要将它的 InputStream 读入 byte [] 。 Apache Commons IO IOUtils 在这里很有用：



  InputStream input = uploadedFile。的getInputStream（）; 
 byte [] image = IOUtils.toByteArray（input）; // Apache公共IO。 
 someEntity.setImage（image）; 
 // ... 
  

或者如果您更喜欢标准的Java API，更详细：



  InputStream input = uploadedFile.getInputStream（）; 
 ByteArrayOutputStream output = new ByteArrayOutputStream（）; 
 byte [] buffer = new byte [10240]; 
 for（int length = 0;（length = input.read（buffer））> 0;）output.write（buffer，0，length）; 
 someEntity.setImage（output.toByteArray（））; 
 // ... 
  




How to convert Part to Blob, so I can store it in MySQL? It is an image. Thank you

My form

<h:form id="form" enctype="multipart/form-data">
        <h:messages/>
        <h:panelGrid columns="2">
            <h:outputText value="File:"/>
            <h:inputFile id="file" value="#{uploadPage.uploadedFile}"/>
        </h:panelGrid>
        <br/><br/>
        <h:commandButton value="Upload File" action="#{uploadPage.uploadFile}"/>
</h:form>

My bean

@Named
@ViewScoped
public class UploadPage {       
    private Part uploadedFile; 

    public void uploadFile(){
    }
}

解决方案

The SQL database BLOB type is in Java represented as byte[]. This is in JPA further to be annotated as @Lob. So, your model basically need to look like this:

@Entity
public class SomeEntity {

    @Lob
    private byte[] image;

    // ...
}

As to dealing with Part, you thus basically need to read its InputStream into a byte[]. Apache Commons IO IOUtils is helpful here:

InputStream input = uploadedFile.getInputStream();
byte[] image = IOUtils.toByteArray(input); // Apache commons IO.
someEntity.setImage(image);
// ...

Or if you prefer standard Java API which is only a bit more verbose:

InputStream input = uploadedFile.getInputStream();
ByteArrayOutputStream output = new ByteArrayOutputStream();
byte[] buffer = new byte[10240];
for (int length = 0; (length = input.read(buffer)) > 0;) output.write(buffer, 0, length);
someEntity.setImage(output.toByteArray());
// ...

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