文件的导入导出（CLOB类型字段）_Oracle_java

1、将数据库某字段的内容导出到指定的文件

数据库表结构如下：

表MAXPRESENTATION

APP

VARCHAR2(10)

PRESENTATION

CLOB

MAXPRESENTATIONID

NUMBER

ROWSTAMP

VARCHAR2(40)

[注]：以APP字段的内容做为导出的文件名，PRESENTATION字段的内容做为该文件的内容，该字段的编码格式为：UTF-8

程序清单如下：

package file;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
import java.sql.Clob;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
/**
*
* 文件导出
*
*
*
* @author songl
*
* @version 1.0 2005.12.2
*/
public class ExpFile {
public static void main(String args[]) throws ClassNotFoundException, IOException {
Connection con = null;
Statement stmt = null;
ResultSet rs = null;
try{
String url = "jdbc:oracle:thin:@IP:1521:system";
DriverManager.registerDriver(new oracle.jdbc.driver.OracleDriver());
con = DriverManager.getConnection(url,"maximo","maximo");
stmt = con.createStatement();

System.out.println("请指定导入的文件名：");
InputStreamReader irFile = new InputStreamReader(System.in);
BufferedReader inFile = new BufferedReader(irFile);
String sFile = inFile.readLine();
sFile = sFile.toUpperCase();
if(sFile!=null && !sFile.equalsIgnoreCase("")) {
rs = stmt.executeQuery("select * from MAXPRESENTATION where APP='"+sFile+"'");
}
else {
rs = stmt.executeQuery("select * from MAXPRESENTATION");
}
while(rs.next()){
//新建文件
System.out.println(rs.getString(1));
String strName = rs.getString(1);
strName = strName+".xml";
File f1= new File("/epmxes/epmxes/res/presentation",strName);
if(f1.isFile()==false) {
try {

f1.createNewFile();

} catch (IOException e) {

e.printStackTrace();

}

String strNR = null;

//读取文件内容

Clob clob = rs.getClob(2);

strNR = clob.getSubString( (long) 1, (int) clob.length());

//写入文件，此处要用字节流来读取，还要指定编码格式，以免乱码

OutputStreamWriter isw = new OutputStreamWriter(new FileOutputStream(f1),"UTF-8");

BufferedWriter bw = new BufferedWriter(isw);

bw.write(strNR,0,strNR.length());

bw.close();

}

else {

System.out.println("文件："+strName+"已经存在！是否覆盖？y/n");

InputStreamReader ir;

BufferedReader in;

ir=new InputStreamReader(System.in);

in=new BufferedReader(ir);

String s=in.readLine();

if(s.equalsIgnoreCase("y")){

System.out.println("文件："+strName+"被覆盖!");

String strNR = null;

Clob clob = rs.getClob(2);

//读取文件内容

strNR = clob.getSubString( (long) 1, (int) clob.length());

System.out.println("文件内容如下:");

System.out.println(strNR);

//写入文件

OutputStreamWriter isw = new OutputStreamWriter(new FileOutputStream(f1),"UTF-8");

System.out.println(isw.getEncoding());

BufferedWriter bw = new BufferedWriter(isw);

bw.write(strNR,0,strNR.length());

bw.close();

}

else if(s.equalsIgnoreCase("n")) {

System.out.println("文件："+strName+"没有被覆盖!");

}

else {

System.out.println("输入的字符有误！请重新运行程序！");

}

}
}
}catch(SQLException ex){
ex.printStackTrace();
}finally{
try{
rs.close();
stmt.close();
con.close();
}catch(SQLException ex){
ex.printStackTrace();
}
}
}
}

2

、将文件内容存入数据库的表中相应的字段

程序清单如下：

package file;
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.io.Writer;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
/**
*
* 导入数据库
*
*
*
* @author songl
*
* @version 1.0 2005.12.2
*/
public class ImpDb {
public static void main(String args[]) {
Connection con = null;
ResultSet resultset = null;
Statement statement = null;
Statement pstmt = null;
try {
System.out.println("请指定导入数据库的文件名：");
InputStreamReader irFile = new InputStreamReader(System.in);
BufferedReader inFile = new BufferedReader(irFile);
String sFile = inFile.readLine();
if (sFile != null && !sFile.equalsIgnoreCase("")) {
File f1 = new File("/epmxes/epmxes/res/presentation/", sFile
+ ".xml");
if (f1.isFile() == true) {
// 读取文件内容
InputStreamReader isr = new InputStreamReader(
new FileInputStream(f1), "UTF-8");
BufferedReader br = new BufferedReader(isr);
String strNR = "";
while (true) {
// 按行读取
String temp = br.readLine();
if (temp == null) {
break;
}
strNR += temp + "/n";
}
br.close();
System.out.println("文件内容如下：");
System.out.println(strNR);
String url = "jdbc:oracle:thin:@IP:1521:system";
DriverManager
.registerDriver(new oracle.jdbc.driver.OracleDriver());
con = DriverManager.getConnection(url, "maximo", "maximo");
// 将文件导入数据库
sFile = sFile.toUpperCase();
con.setAutoCommit(false);
String sql = "update MAXPRESENTATION set PRESENTATION = empty_clob() where APP='"
+ sFile + "'";
pstmt = con.createStatement();
pstmt.executeUpdate(sql);
statement = con.createStatement();
String sql2 = "select PRESENTATION from MAXPRESENTATION where APP='"
+ sFile + "'";
resultset = statement.executeQuery(sql2);
oracle.sql.CLOB contents = null;
while (resultset.next()) {
// 要使用oracle中的resultset对象
contents = (oracle.sql.CLOB) resultset
.getClob("PRESENTATION");
}
Writer out = contents.getCharacterOutputStream();
out.write(strNR);
out.flush();
out.close();
con.commit();
con.setAutoCommit(true);
System.out.println("导入数据库成功！");
}
else {
System.out.println("不存在该文件！");
}
}
else {
System.out.println("请输入文件名！");
}
} catch (Exception ex) {
try {
if (con != null) {
con.rollback();
}
} catch (SQLException e) {
e.printStackTrace();
}
} finally {
try {
if (resultset != null) {
resultset.close();
}
if (statement != null) {
statement.close();
}
if (pstmt != null) {
pstmt.close();
}
if (con != null) {
con.close();
}
} catch (SQLException ex) {
ex.printStackTrace();
}
}
}
}