java oracle数据备份

在企业级应用开发中，数据备份是非常重要的一项工作。数据备份能够保证数据的安全，同时也能够避免意外情况导致数据的丢失。在 Java 企业应用中，我们可以使用 Oracle 数据库进行数据备份。下面，我们将介绍如何通过 Java 代码进行 Oracle 数据备份。

首先，我们需要在 Java 应用中连接 Oracle 数据库。我们可以使用 JDBC 进行连接。以下是连接 Oracle 数据库的示例代码：

Class.forName("oracle.jdbc.driver.OracleDriver");
String url = "jdbc:oracle:thin:@localhost:1521:orcl";
String user = "scott";
String password = "tiger";
Connection conn = DriverManager.getConnection(url,user,password);

在连接成功之后，我们需要准备要备份的数据。我们需要执行 sql 语句，将需要备份的数据查询出来。以下是查询数据的示例代码：

Statement stmt = conn.createStatement();
String sql = "SELECT * FROM employees";
ResultSet rs = stmt.executeQuery(sql);

在将数据备份到本地之前，我们需要将数据导出到 Oracle 数据库的数据文件中。以下是导出数据的示例代码：

String dataFileName = "/tmp/employees.data";
String controlFileName = "/tmp/employees.ctl";
String logFileName = "/tmp/employees.log";
String delimiter = ",";
String quoteChar = "\"";
String escapeChar = "\\";
String sql = "SELECT * FROM employees";
String ctl =
"OPTIONS (SKIP=1)\n" +
"LOAD DATA\n" +
"INFILE '" + dataFileName + "'\n" +
"BADFILE '" + logFileName + "'\n" +
"disCARDFILE '" + logFileName + "'\n" +
"APPEND INTO TABLE employees\n" +
"FIELDS TERMINATED BY '" + delimiter + "'\n" +
"OPTIONALLY ENCLOSED BY '" + quoteChar + "'\n" +
"ESCAPED BY '" + escapeChar + "'\n" +
"TRAILING NULLCOLS\n" +
"(" +
"EMPLOYEE_ID," +
"FirsT_NAME," +
"LAST_NAME," +
"EMAIL," +
"PHONE_NUMBER," +
"HIRE_DATE," +
"JOB_ID," +
"SALARY," +
"COMMISSION_PCT," +
"MANAGER_ID," +
"DEPARTMENT_ID" +
")\n";
PrintWriter ctlWriter = new PrintWriter(controlFileName);
ctlWriter.println(ctl);
ctlWriter.close();
PrintWriter dataWriter = new PrintWriter(dataFileName);
while (rs.next()) {
dataWriter.println(rs.getString("EMPLOYEE_ID") + delimiter +
rs.getString("FirsT_NAME") + delimiter +
rs.getString("LAST_NAME") + delimiter +
rs.getString("EMAIL") + delimiter +
rs.getString("PHONE_NUMBER") + delimiter +
rs.getString("HIRE_DATE") + delimiter +
rs.getString("JOB_ID") + delimiter +
rs.getString("SALARY") + delimiter +
rs.getString("COMMISSION_PCT") + delimiter +
rs.getString("MANAGER_ID") + delimiter +
rs.getString("DEPARTMENT_ID")
);
}
dataWriter.close();

在将数据导出到数据文件之后，我们需要将数据文件进行备份。以下是将数据文件备份到本地的示例代码：

File dataFile = new File(dataFileName);
FileInputStream dataInputStream = new FileInputStream(dataFile);
File backupFile = new File("/tmp/employees.data.backup");
FileOutputStream backupOutputStream = new FileOutputStream(backupFile);
byte[] buffer = new byte[1024];
int length;
while ((length = dataInputStream.read(buffer)) > 0) {
backupOutputStream.write(buffer,length);
}
backupOutputStream.close();
dataInputStream.close();

到此为止，我们已经完成了数据备份的整个过程。通过以上的 Java 代码，我们可以轻松的将 Oracle 数据库中的数据备份到本地。