mybatis oracle BLOB类型字段保存与读取

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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：

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：

package com.test.entity; import java.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：

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.test.dao.BlobFieldDao"> <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> <sql id="blobFieldJoins">
</sql> <select id="get" resultType="blobField">
SELECT
<include refid="blobFieldColumns" />
FROM BLOB_FIELD a
<include refid="blobFieldJoins" />
WHERE a.ID = #{id}
</select> <select id="findList" resultType="blobField">
SELECT
<include refid="blobFieldColumns" />
FROM BLOB_FIELD a
<include refid="blobFieldJoins" />
</select> <insert id="insert">
INSERT INTO BLOB_FIELD(
ID ,
TAB_NAME ,
TAB_PKID_VALUE ,
BLOB_COL_NAME ,
BLOB_COL_VALUE
) VALUES (
#{id},
#{tabName},
#{tabPkidValue},
#{blobColName},
#{blobColValue,jdbcType=BLOB}
)
</insert> <update id="update">
UPDATE BLOB_FIELD SET
TAB_NAME = #{tabName},
TAB_PKID_VALUE = #{tabPkidValue},
BLOB_COL_NAME = #{blobColName},
BLOB_COL_VALUE = #{blobColValue}
WHERE ID = #{id}
</update>
<delete id="delete">
DELETE FROM BLOB_FIELD
WHERE ID = #{id}
</delete> </mapper>

3、controller代码如下：

a、保存BLOB字段代码

/**
* 附件上传
*
* @param testId
* 主表Id
* @param request
* @return
* @throws UnsupportedEncodingException
*/
@RequiresPermissions("exc:exceptioninfo:feedback")
@RequestMapping(value = "attachment", method = RequestMethod.POST)
@ResponseBody
public Map<String, Object> uploadAttachment(@RequestParam(value = "testId", required = true) String testId, HttpServletRequest request)
throws UnsupportedEncodingException {
Map<String, Object> result = new HashMap<String, Object>(); MultipartHttpServletRequest multipartRequest = (MultipartHttpServletRequest) request;
// 获得文件
MultipartFile multipartFile = multipartRequest.getFile("Filedata");// 与前端设置的fileDataName属性值一致
String filename = multipartFile.getOriginalFilename();// 文件名称
InputStream is = null;
try {
//读取文件流
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 {
IOUtils.closeQuietly(is);
}
return result;
}

b、读取BLOB字段

/**
* 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- 8"); // fileName.getBytes("UTF-8")处理safari的乱码问题
String fileName = new String(bytes, "ISO-8859-1");
// 设置输出的格式
response.setContentType("multipart/form-data");
response.setHeader("Content-Disposition", "attachment;fileName=" + URLEncoder.encode(attachmentName, "UTF-8"));
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();
}
}