oracle10对clob的处理简单化了
在oracle10g中对于大字段clob的处理简化了,可以像varchar那样的setString(str)和getString("colum_name)来插入和取值了.
不需要再像9i 那样用流进写入读出了.
但是需要使用PreparedStatement ,(用Statement和话会添不了值,我测试没有通过)
处理clob的完整方法方法如下,
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.Statement;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import oracle.jdbc.OracleDriver;
import java.io.IOException;
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.util.Properties;
public class ClobManipulationIn10g {
private Connection conn = null;
private String url = null;
private String user = null;
private String password = null;
private Properties props = new Properties();
private String fileName = null;
public ClobManipulationIn10g(String fileName) {
this.fileName = fileName;
}
public static void main(String[] args) throws SQLException {
ClobManipulationIn10g clobManipulationIn10g = new ClobManipulationIn10g("C://工作交流单[规].html");
DriverManager.registerDriver(new OracleDriver());
String dbUrl = "jdbc:oracle:thin:@localhost:1521:xe";
clobManipulationIn10g.url = dbUrl;
clobManipulationIn10g.user = "shanxi";
clobManipulationIn10g.password = "shanxi";
clobManipulationIn10g.props.put("user", clobManipulationIn10g.user);
clobManipulationIn10g.props.put("password", clobManipulationIn10g.password);
clobManipulationIn10g.props.put("SetBigStringTryClob", "true");
clobManipulationIn10g.selectClob();
}
private void insertClob() throws SQLException {
PreparedStatement pstmt = null;
PreparedStatement ps2=null;
try {
if ((conn == null) || conn.isClosed()) {
conn = DriverManager.getConnection(this.url, this.props);
}
String str = this.readFile();
String sql="insert into tbs(tid,tname,tclob) values(1,'aaaaa',empty_clob())";
String sql2="update tbs set tclob=?";
pstmt = conn.prepareStatement(sql);
pstmt.executeUpdate();
pstmt = conn.prepareStatement(sql2);
pstmt.setString(1, str);
pstmt.executeUpdate();
} catch (SQLException sqlex) {
System.out.println("SQLException while connecting and inserting into " +
"the database table: " + sqlex.toString());
} catch (Exception ex) {
System.out.println("Exception while connecting and inserting into the" +
" database table: " + ex.toString());
} finally {
if (pstmt != null) {
pstmt.close();
}
if (conn != null) {
conn.close();
}
}
}
private void updateClob() throws SQLException {
PreparedStatement pstmt = null;
try {
if ((conn == null) || conn.isClosed()) {
conn = DriverManager.getConnection(this.url, this.props);
}
String str = this.readFile();
String sql = "update tbs set tname='bbbb', tclob=? where tid=1";
pstmt = conn.prepareStatement(sql);
pstmt.setString(1, str);
pstmt.executeUpdate();
} catch (SQLException sqlex) {
System.out.println("SQLException while connecting and inserting into " +
"the database table: " + sqlex.toString());
} catch (Exception ex) {
System.out.println("Exception while connecting and inserting into the" +
" database table: " + ex.toString());
} finally {
if (pstmt != null) {
pstmt.close();
}
if (conn != null) {
conn.close();
}
}
}
private void selectClob() throws SQLException {
PreparedStatement pstmt = null;
ResultSet rset = null;
try {
if ((conn == null) || conn.isClosed()) {
conn = DriverManager.getConnection(this.url, this.props);
}
String sqlCall = "SELECT * FROM tbs";
pstmt = conn.prepareStatement(sqlCall);
rset = pstmt.executeQuery();
while (rset.next()) {
String idval=rset.getString("tid");
String nameval=rset.getString("tname");
String clobVal = rset.getString("tclob");
System.out.println("CLOB length: " + clobVal.length());
System.out.println(idval);
System.out.println(nameval);
System.out.println(clobVal);
}
} catch (SQLException sqlex) {
System.out.println("SQLException while connecting and querying the " +
"database table: " + sqlex.toString());
} catch (Exception ex) {
System.out.println("Exception while connecting and querying the " +
"database table: " + ex.toString());
} finally {
if (rset != null) {
rset.close();
}
if (pstmt != null) {
pstmt.close();
}
if (conn != null) {
conn.close();
}
}
}
private void checkTables() {
Statement stmt = null;
ResultSet rset = null;
try {
if ((conn == null) || conn.isClosed()) {
conn = DriverManager.getConnection(this.url, this.props);
}
stmt = conn.createStatement();
rset = stmt.executeQuery(" SELECT table_name FROM user_tables " +
" WHERE table_name = 'aaa' ");
if (!rset.next()) {
stmt.executeUpdate(" CREATE TABLE aaa(clob_col CLOB)");
}
} catch (SQLException sqlEx) {
System.out.println("Could not create table aaa : " + sqlEx.toString());
} finally {
try {
if (rset != null) {
rset.close();
}
if (stmt != null) {
stmt.close();
}
if (conn != null) {
conn.close();
}
} catch (SQLException ex) {
System.out.println("Could not close objects in checkTables method : " + ex.toString());
}
}
}
private String readFile() throws FileNotFoundException, IOException {
BufferedReader br = new BufferedReader(new FileReader(fileName));
String nextLine = "";
StringBuffer sb = new StringBuffer();
while ((nextLine = br.readLine()) != null) {
sb.append(nextLine);
}
String clobData = sb.toString();
return clobData;
}
}