一、BLOB字段
BLOB是指二进制大对象也就是英文Binary Large Object的所写，而CLOB是指大字符对象也就是英文Character Large Object的所写。其中BLOB是用来存储大量二进制数据的；CLOB用来存储大量文本数据。BLOB通常用来保存图片、文件等二进制类型的数据。
二、使用mybatis操作blob
1、表结构如下：
sql;">
create table BLOB_FIELD
(
ID VARCHAR2(64 BYTE) not null,TAB_NAME VARCHAR2(64 BYTE) not null,TAB_PKID_VALUE VARCHAR2(64 BYTE) not null,CLOB_COL_NAME VARCHAR2(64 BYTE) not null,CLOB_COL_VALUE CLOB,constraint PK_BLOB_FIELD primary key (ID)
);
2、实体代码如下：
sql.Clob;
/**
* 大字段
*/
public class BlobField {
private String tabName;// 表名
private String tabPkidValue;// 主键值
private String blobColName;// 列名
private byte[] blobColValue;// 列值 clob类型
public String getTabName() {
return tabName;
}
public void setTabName(String tabName) {
this.tabName = tabName;
}
public String getTabPkidValue() {
return tabPkidValue;
}
public void setTabPkidValue(String tabPkidValue) {
this.tabPkidValue = tabPkidValue;
}
public String getBlobColName() {
return blobColName;
}
public void setBlobColName(String blobColName) {
this.blobColName = blobColName;
}
public byte[] getBlobColValue() {
return blobColValue;
}
public void setBlobColValue(byte[] blobColValue) {
this.blobColValue = blobColValue;
}
}
3、mybatis sql代码如下：
sql;">
<?xml version="." encoding="UTF-" ?>
sql id="blobFieldColumns">
a.ID AS id,a.TAB_NAME AS tabName,a.TAB_PKID_VALUE AS tabPkidValue,a.BLOB_COL_NAME AS blobColName,a.BLOB_COL_VALUE AS blobColValue
<sql id="blobFieldJoins">
FROM BLOB_FIELD a
3、controller代码如下：
a、保存BLOB字段代码
上传
*
* @param testId
* 主表Id
* @param request
* @return
* @throws UnsupportedEncodingException
*/
@RequiresPermissions("exc:exceptioninfo:Feedback")
@RequestMapping(value = "attachment",method = RequestMethod.POST)
@ResponseBody
public Map uploadAttachment(@RequestParam(value = "testId",required = true) String testId,HttpServletRequest request)
throws UnsupportedEncodingException {
Map result = new HashMap();
MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) request;
// 获得<a href="https://www.jb51.cc/tag/wenjian/" target="_blank" class="keywords">文件</a>
MultipartFile multipartFile = multipartRequest.getFile("Filedata");// 与前端设置的fileD<a href="https://www.jb51.cc/tag/atan/" target="_blank" class="keywords">atan</a>ame<a href="https://www.jb51.cc/tag/shuxing/" target="_blank" class="keywords">属性</a>值一致
String filename = multipartFile.getOriginalFilename();// <a href="https://www.jb51.cc/tag/wenjian/" target="_blank" class="keywords">文件</a><a href="https://www.jb51.cc/tag/mingcheng/" target="_blank" class="keywords">名称</a>
InputStream is = null;
try {
//读取<a href="https://www.jb51.cc/tag/wenjian/" target="_blank" class="keywords">文件</a>流
is = multipartFile.getInputStream();
byte[] bytes = FileCopyUtils.copyToByteArray(is);
BlobField blobField = new BlobField();
blobField.setTabName("testL");
blobField.setTabPkidValue(testId);
blobField.setBlobColName("attachment");
blobField.setBlobColValue(bytes);
//保存blob字段
this.testService.save(blobField,testId,filename);
result.put("flag",true);
result.put("attachmentId",blobField.getId());
result.put("attachmentName",filename);
} catch (IOException e) {
e.printStackTrace();
result.put("flag",false);
} finally {
<a href="https://www.jb51.cc/tag/IoU/" target="_blank" class="keywords">IoU</a>tils.closeQuietly(is);
}
return result;}
b、读取BLOB字段
sql;">
/**
* 下载附件
*
* @param attachmentId
* @return
*/
@RequiresPermissions("exc:exceptioninfo:view")
@RequestMapping(value = "download",method = RequestMethod.GET)
public void download(@RequestParam(value = "attachmentId",required = true) String attachmentId,@RequestParam(value = "attachmentName",required = true) String attachmentName,HttpServletRequest
request,HttpServletResponse response) {
ServletOutputStream out = null;
try {
response.reset();
String userAgent = request.getHeader("User-Agent");
byte[] bytes = userAgent.contains("MSIE") ? attachmentName.getBytes() : attachmentName.getBytes("UTF-
"); // fileName.getBytes("UTF-")处理safari的乱码问题
String fileName = new String(bytes,"ISO--");
// 设置输出的格式
response.setContentType("multipart/form-data");
response.setHeader("Content-Disposition","attachment;fileName=" + URLEncoder.encode(attachmentName,"UTF-"));
BlobField blobField = this.blobFieldService.get(attachmentId);
//获取blob字段
byte[] contents = blobField.getBlobColValue();
out = response.getOutputStream();
//写到输出流
out.write(contents);
out.flush();
} catch (IOException e) {
e.printStackTrace();
}
}
本例子将文件上传并保存到BLOB类型字段字段，下载的时候读取BLOB字段，并写入成输出流。
以上就是本文的全部叙述，希望对大家有所帮助。
原文链接：https://www.f2er.com/oracle/65173.html