展示JDBC存取ORACLE大型数据对象LOB几种情况的示范类
展示JDBC存取ORACLE大型数据对象LOB几种情况的示范类
import java.io.*;
import java.util.*;
import java.sql.*;
public class LobPros
{
/**
* ORACLE驱动程序
*/
private static final String DRIVER = "oracle.jdbc.driver.OracleDriver";
/**
* ORACLE连接用URL
*/
private static final String URL = "jdbc:oracle:thin:@test2000:1521:orac";
/**
* 用户名
*/
private static final String USER = "user";
/**
* 密码
*/
private static final String PASSWORD = "pswd";
/**
* 数据库连接
*/
private static Connection conn = null;
/**
* SQL语句对象
*/
private static Statement stmt = null;
/**
* @roseuid 3EDA089E02BC
*/
public LobPros()
{
}
/**
* 往数据库中插入一个新的CLOB对象
*
* @param infile - 数据文件
* @throws java.lang.Exception
* @roseuid 3EDA04A902BC
*/
public static void clobInsert(String infile) throws Exception
{
/* 设定不自动提交 */
boolean defaultCommit = conn.getAutoCommit();
conn.setAutoCommit(false);
try {
/* 插入一个空的CLOB对象 */
stmt.executeUpdate("INSERT INTO TEST_CLOB VALUES ('111', EMPTY_CLOB())");
/* 查询此CLOB对象并锁定 */
ResultSet rs = stmt.executeQuery("SELECT CLOBCOL FROM TEST_CLOB WHERE ID='111' FOR UPDATE");
while (rs.next()) {
/* 取出此CLOB对象 */
oracle.sql.CLOB clob = (oracle.sql.CLOB)rs.getClob("CLOBCOL");
/* 向CLOB对象中写入数据 */
BufferedWriter out = new BufferedWriter(clob.getCharacterOutputStream());
BufferedReader in = new BufferedReader(new FileReader(infile));
int c;
while ((c=in.read())!=-1) {
out.write(c);
}
in.close();
out.close();
}
/* 正式提交 */
conn.commit();
} catch (Exception ex) {
/* 出错回滚 */
conn.rollback();
throw ex;
}
/* 恢复原提交状态 */
conn.setAutoCommit(defaultCommit);
}
/**
* 修改CLOB对象（是在原CLOB对象基础上进行覆盖式的修改）
*
* @param infile - 数据文件
* @throws java.lang.Exception
* @roseuid 3EDA04B60367
*/
public static void clobModify(String infile) throws Exception
{
/* 设定不自动提交 */
boolean defaultCommit = conn.getAutoCommit();
conn.setAutoCommit(false);
try {
/* 查询CLOB对象并锁定 */
ResultSet rs = stmt.executeQuery("SELECT CLOBCOL FROM TEST_CLOB WHERE ID='111' FOR UPDATE");
while (rs.next()) {
/* 获取此CLOB对象 */
oracle.sql.CLOB clob = (oracle.sql.CLOB)rs.getClob("CLOBCOL");
/* 进行覆盖式修改 */
BufferedWriter out = new BufferedWriter(clob.getCharacterOutputStream());
BufferedReader in = new BufferedReader(new FileReader(infile));
int c;
while ((c=in.read())!=-1) {
out.write(c);
}
in.close();
out.close();
}
/* 正式提交 */
conn.commit();
} catch (Exception ex) {
/* 出错回滚 */
conn.rollback();
throw ex;
}
/* 恢复原提交状态 */
conn.setAutoCommit(de