在做專案的時候，圖片一般是存在單獨的伺服器中，資料庫中只存url地址，這樣做事比較好的，減輕了資料庫的壓力，存取圖片的時候也簡單。然而，也不排除直接將二進位制檔案存到資料庫中的情況，這種做法，無論是存還是取都不方便，也增加了資料庫的壓力，所以儘量避免這種做法。

• JavaBean

public class CustomerPMProduct {
    private String name;//產品名稱
    private Float weightAu;//含金量
    private String standard;//規格
    private Float remainAmount;//剩餘量
 

    private byte[] thumbnail;//縮圖，這個就是二進位制欄位
    public String getStandard() {
        return standard;
    }
    public void setStandard(String standard) {
        this.standard = standard;
    }

    public byte[] getThumbnail() {
        return thumbnail;
    }

    public void setThumbnail(byte[] thumbnail) {
        this
 
.thumbnail = thumbnail;
    }


    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public Float getWeightAu() {
        return weightAu;
    }

    public void setWeightAu(Float weightAu) {
        this.weightAu = weightAu;
    }

    public
 
 Float getRemainAmount() {
        return remainAmount;
    }

    public void setRemainAmount(Float remainAmount) {
        this.remainAmount = remainAmount;
    }

}

• mapper.java介面

@Component
public interface CustomerPMProductMapper {
    CustomerPMProduct selectPMProduct();
}

• mapper.xml檔案

<select id="selectPMProduct" resultType="com.yihuisoft.testprojectbiz.entity.CustomerPMProduct">
        SELECT name,
          weight_au weightAu,
          standard,
          REMAIN_AMOUNT remainAmount,
          THUMBNAIL01 thumbnail
        FROM
          (SELECT name,
            weight_au,
            standard,
            REMAIN_AMOUNT ,
            THUMBNAIL01
          FROM PM_PRODUCT
          WHERE exp_yield IS NOT NULL
          ORDER BY exp_yield DESC
          )
        WHERE rownum=1
    </select>

• service

 public OutDTO selectPMProduct(InDTO inDTO){
        OutDTO outDTO = new OutDTO();
        CustomerPMProduct pmProduct = wealthSuccessionMapper.selectPMProduct();
        JSONObject jsonObject = new JSONObject();
        jsonObject.put("data",pmProduct);
        outDTO.setData(jsonObject);
        return outDTO;
    }

• 前端顯示
• image標籤

<img id="img1" src="" height="128px" width="200px">

• js

document.getElementById("img1").src = "data:image/png;base64,"+this.pmProduct.thumbnail;