标签：value prope rac weight efault space 方法 创建 return
前言：
BLOB用来存储大量二进制数据。如图片、音乐等，转为二进制数再存储
CLOB用来存储大量文本数据。如HTML页面等，varchar2最大是4000，预计会超过4000的用Clob
正文：
1，我用的是java + mybatis，直接用String处理就可以了。String最大能存4G
数据库：创建表
-- Create table create table CLOB_TEST ( id VARCHAR2(32) default sys_guid(), content CLOB )
实体类：
package com.bf.test.entity; public class ClobTest { private String id; private String content; public String getId() { return id; } public void setId(String id) { this.id = id; } public String getContent() { return content; } public void setContent(String content) { this.content = content; } }
查询语句：sql.xml
<?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.bf.labor.dao.IClobDao"> <resultMap id="BaseResultMap" type="com.bf.test.entity.ClobTest" > <result column="ID" property="id" jdbcType="VARCHAR" /> <result column="CONTENT" property="content" jdbcType="VARCHAR" /> </resultMap> <select id="getList" resultMap="BaseResultMap"> select * from CLOB_TEST </select> <insert id="insert" > insert into CLOB_TEST (CONTENT) values (#{content}) </insert> </mapper>
测试类：
package com.test; import java.util.List; import org.junit.Test; import org.junit.runner.RunWith; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.test.context.ContextConfiguration; import org.springframework.test.context.junit4.SpringJUnit4ClassRunner; import org.springframework.test.context.web.WebAppConfiguration; import com.bf.labor.entity.ClobTest; import com.bf.labor.service.ClobService; @RunWith(SpringJUnit4ClassRunner.class) @WebAppConfiguration("web") @ContextConfiguration(locations = "file:G:/WIM/Source/webapp/WEB-INF/spring-core-config.xml") public class ClobServiceTest { @Autowired private ClobService clobService; @Test public void test() { List<ClobTest> list = this.clobService.getList(); System.out.println("test=" + list); } @Test public void test2() { String str = ""; for (int i = 0; i < 5000; i++) { str = str + "正"; } System.out.println("str=" + str); ClobTest newInfo = new ClobTest(); newInfo.setContent(str); this.clobService.insert(newInfo); } }
2，Clob字段转换成字符串。数据库数据迁移的时候要格外注意这一点，不做处理的话，Clob字段的值为空
方法1：dbms_lob.substr()
注意：dbms_lob.substr(content)，超过4000字符，会报错
参考博客：
Oracle中将Clob字段转换成字符串 - sqyNick - CSDN博客
https://blog.csdn.net/u010670151/article/details/52210333
标签：value prope rac weight efault space 方法 创建 return
原文地址：https://www.cnblogs.com/huashengweilong/p/11355606.html
