MYSQL 转 ORACLE CLOB类型

MYSQL中用LOGTEXT表示oracle中的CLOB类型。

Oracle

CLOB

Oracle 9i 及以前，最大4G字符数据 Oracle10g 最大4G*数据库块大小的字符数据

MySQL

LONGTEXT

最大长度为4,294,967,295或4GB(232–1)字符的TEXT列。LONGTEXT列的最大有效(允许的)长度取决于客户端/服务器协议中配置最大包大小和可用的内存。

LONGBLOB

最大长度为4,294,967,295或4GB(232–1)字节的BLOB列。LONGBLOB列的最大有效(允许的)长度取决于客户端/服务器协议中配置最大包大小和可用的内存。

既然你是从数据库取出CLOB字段，那么不用resultset那是用什么取出的。

如果从数据库里面取出的是CLOB字段，为什么会变成String类型呢。

String转CLOB，下面是个例子

public class TestDB {

public static void main(String[] args) {

try {

/** Loading the driver*/

Class.forName("com.oracle.jdbc.Driver")

/** Getting Connection*/

Connection con = DriverManager.getConnection("jdbc:oracle://localhost:3306/test","test","test")

PreparedStatement pstmt = con.prepareStatement("insert into Emp(id,name,description)values(?,?,?)")

pstmt.setInt(1,5)

pstmt.setString(2,"Das")

// Create a big CLOB value...AND inserting as a CLOB

StringBuffer sb = new StringBuffer(400000)

sb.append("This is the Example of CLOB ..")

String clobValue = sb.toString()

pstmt.setString(3, clobValue)

int i= pstmt.executeUpdate()

System.out.println("Done Inserted")

pstmt.close()

con.close()

// Retrive CLOB values

Connection con = DriverManager.getConnection("jdbc:oracle://localhost:3306/test","test","test")

PreparedStatement pstmt = con.prepareStatement("select * from Emp where id=5")

ResultSet rs = pstmt.executeQuery()

Reader instream = null

int chunkSize

if(rs.next()){

String name = rs.getString("name")

java.sql.Clob clob = result.getClob("description")

StringBuffer sb1 = new StringBuffer()

chunkSize = ((oracle.sql.CLOB)clob).getChunkSize()

instream = clob.getCharacterStream()

BufferedReader in = new BufferedReader(instream)

String line = null

while ((line = in.readLine()) != null) {

sb1.append(line)

}

if(in != null){

in.close()

}

String clobdata = sb1.toString()// this is the clob data converted into string

}

} catch (Exception e) {

e.printStackTrace()

}

}

}

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