JDBC存取ORACLE大型數據對象LOB幾種情況的示范類
2024-08-29 13:40:56
供稿：網友
import java.io.*;
import java.util.*;
import java.sql.*;
public class LobPRos
{
/**
* Oracle驅動程序
*/
private static final String DRIVER = "oracle.jdbc.driver.OracleDriver";
/**
* ORACLE連接用URL
*/
private static final String URL = "jdbc:oracle:thin:@test2000:1521:orac";
/**
* 用戶名
*/
private static final String USER = "user";
/**
* 密碼
*/
private static final String PASSWord = "pswd";
/**
* 數據庫連接
*/
private static Connection conn = null;
/**
* SQL語句對象
*/
private static Statement stmt = null;
/**
* @roseuid 3EDA089E02BC
*/
public LobPros()
{
}
/**
* 往數據庫中插入一個新的CLOB對象
*
* @param infile - 數據文件
* @throws java.lang.Exception
* @roseuid 3EDA04A902BC
*/
public static void clobInsert(String infile) throws Exception
{
/* 設定不自動提交 */
boolean defaultCommit = conn.getAutoCommit();
conn.setAutoCommit(false);
try {
/* 插入一個空的CLOB對象 */
stmt.executeUpdate("INSERT INTO TEST_CLOB VALUES ('111', EMPTY_CLOB())");
/* 查詢此CLOB對象并鎖定 */
ResultSet rs = stmt.executeQuery("SELECT CLOBCOL FROM TEST_CLOB WHERE ID='111' FOR UPDATE");
while (rs.next()) {
/* 取出此CLOB對象 */
oracle.sql.CLOB clob = (oracle.sql.CLOB)rs.getClob("CLOBCOL");
/* 向CLOB對象中寫入數據 */
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) {
/* 出錯回滾 */
conn.rollback();
throw ex;
}
/* 恢復原提交狀態 */
conn.setAutoCommit(defaultCommit);
}
/**
* 修改CLOB對象（是在原CLOB對象基礎上進行覆蓋式的修改）
*
* @param infile - 數據文件
* @throws java.lang.Exception
* @roseuid 3EDA04B60367
*/
public static void clobModify(String infile) throws Exception
{
/* 設定不自動提交 */
boolean defaultCommit = conn.getAutoCommit();
conn.setAutoCommit(false);
try {
/* 查詢CLOB對象并鎖定 */
ResultSet rs = stmt.executeQuery("SELECT CLOBCOL FROM TEST_CLOB WHERE ID='111' FOR UPDATE");
while (rs.next()) {
/* 獲取此CLOB對象 */
oracle.sql.CLOB clob = (oracle.sql.CLOB)rs.getClob("CLOBCOL");
/* 進行覆蓋式修改 */
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) {
/* 出錯回滾 */
conn.rollback();
throw ex;
}
/* 恢復原提交狀態 */
conn.setAutoCommit(defaultCommit);
}
/**
* 替換CLOB對象（將原CLOB對象清除，換成一個全新的CLOB對象）
*
* @param infile - 數據文件
* @throws java.lang.Exception
* @roseuid 3EDA04BF01E1
*/
public static void clobReplace(String infile) throws Exception
{
/* 設定不自動提交 */
boolean defaultCommit = conn.getAutoCommit();
conn.setAutoCommit(false);
try {
/* 清空原CLOB對象 */
stmt.executeUpdate("UPDATE TEST_CLOB SET CLOBCOL=EMPTY_CLOB() WHERE ID='111'");
/* 查詢CLOB對象并鎖定 */
ResultSet rs = stmt.executeQuery("SELECT CLOBCOL FROM TEST_CLOB WHERE ID='111' FOR UPDATE");
while (rs.next()) {
/* 獲取此CLOB對象 */
oracle.sql.CLOB clob = (oracle.sql.CLOB)rs.getClob("CLOBCOL");
/* 更新數據 */
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) {
/* 出錯回滾 */
conn.rollback();
throw ex;
}
/* 恢復原提交狀態 */
conn.setAutoCommit(defaultCommit);
}
/**
* CLOB對象讀取
*
* @param outfile - 輸出文件名
* @throws java.lang.Exception
* @roseuid 3EDA04D80116
*/
public static void clobRead(String outfile) throws Exception
{
/* 設定不自動提交 */
boolean defaultCommit = conn.getAutoCommit();
conn.setAutoCommit(false);
try {
/* 查詢CLOB對象 */
ResultSet rs = stmt.executeQuery("SELECT * FROM TEST_CLOB WHERE ID='111'");
while (rs.next()) {
/* 獲取CLOB對象 */
oracle.sql.CLOB clob = (oracle.sql.CLOB)rs.getClob("CLOBCOL");
/* 以字符形式輸出 */
BufferedReader in = new BufferedReader(clob.getCharacterStream());
BufferedWriter out = new BufferedWriter(new FileWriter(outfile));
int c;
while ((c=in.read())!=-1) {
out.write(c);
}
out.close();
in.close();
}
} catch (Exception ex) {
conn.rollback();
throw ex;
}
/* 恢復原提交狀態 */
conn.setAutoCommit(defaultCommit);
}
/**
* 向數據庫中插入一個新的BLOB對象
*
* @param infile - 數據文件
* @throws java.lang.Exception
* @roseuid 3EDA04E300F6
*/
public static void blobInsert(String infile) throws Exception
{
/* 設定不自動提交 */
boolean defaultCommit = conn.getAutoCommit();
conn.setAutoCommit(fal
