This topic describes how to use the Oracle XA feature to implement distributed transactions.
Import Oracle XA
To use the Oracle XA feature, execute the following statements to import related objects:
import oracle.jdbc.xa.OracleXid;
import oracle.jdbc.xa.OracleXAException;
import oracle.jdbc.pool.*;
import oracle.jdbc.xa.client.*;
import javax.transaction.xa.*;
The oracle.jdbc.pool package has classes for the connection pool feature, with XA-related classes as subclasses.
Alternatively, if the code is to be run inside the database and you need to access the database for SQL operations, import oracle.jdbc.xa.server instead of oracle.jdbc.xa.client. Syntax:
import oracle.jdbc.xa.server.*;
The client and server software packages provide versions of the OracleXADataSource, OracleXAConnection, and OracleXAResource classes. The abstract versions of these three classes are in the oracle.jdbc.xa package.
Oracle XA Code examples
The following takes the processing of XA transactions for example:
Use
XA STARTto start XA transactions and set them to be in theACTIVEstate.For an XA transaction in the
ACTIVEstate, execute the SQL statements that constitute the transaction and then execute theXA ENDstatement. TheXA ENDstatement sets the transaction to be in theIDLEstate.For an XA transaction in the
IDLEstate, you can execute theXA PREPAREorXA COMMIT... ONE PHASEstatement.The
XA PREPAREstatement sets the transaction to be in thePREPAREDstate. In this case, theXA RECOVERstatement includes the value ofxidof the transaction in its output, becauseXA RECOVERlists all XA transactions in thePREPAREDstate.The
XA COMMIT ... ONE PHASEstatement prepares and commits transactions. In this case, theXA RECOVERstatement does not list the values ofxidbecause the transactions are terminated.
For an XA transaction in the
PREPAREDstate, you can execute theXA COMMITstatement to commit and terminate the transaction, or executeXA ROLLBACKto roll back and terminate the transaction.
public static void initClass() throws SQLException {
createTable(tableName1, "c1 int,c2 int");
createTable(tableName2, "c1 int,c2 int");
createTable(tableName3, "c1 varchar(200)");
}
public void obOracleXAOne() throws Exception {
Assume.assumeTrue(sharedUsePrepare());
Connection conn = setConnection();
conn.createStatement().execute(" insert into " + tableName1 + " values(1,2)");
JDBC4MysqlXAConnection mysqlXAConnection = new JDBC4MysqlXAConnection(
(OceanBaseConnection) conn);
String gtridStr = "gtrid_test_wgs_ob_oracle_xa_one";
String bqualStr = "bqual_test_wgs_ob_oracle_xa_one";
Xid xid = new MysqlXid(gtridStr.getBytes(), bqualStr.getBytes(), 123);
try {
mysqlXAConnection.start(xid, XAResource.TMNOFLAGS);
PreparedStatement pstmt = null;
ResultSet rs = null;
pstmt = conn.prepareStatement("select c1 from " + tableName1);
rs = pstmt.executeQuery();
while (rs.next()) {
System.out.println(rs.getInt(1));
}
pstmt.close();
pstmt = conn.prepareStatement("insert into " + tableName1 + " (c1, c2) values(?, ?)");
pstmt.setInt(1, 12);
pstmt.setInt(2, 12);
pstmt.executeUpdate();
mysqlXAConnection.end(xid, XAResource.TMSUCCESS);
mysqlXAConnection.prepare(xid);
mysqlXAConnection.commit(xid, false);
} catch (Exception e) {
e.printStackTrace();
mysqlXAConnection.rollback(xid);
throw e;
}
}
public void obOracleXAOnePhase() throws Exception {
Assume.assumeTrue(sharedUsePrepare());
Connection conn = null;
conn = setConnection();
conn.createStatement().execute(" insert into " + tableName2 + " values(1,2)");
JDBC4MysqlXAConnection mysqlXAConnection = new JDBC4MysqlXAConnection(
(OceanBaseConnection) conn);
String gtridStr = "gtrid_test_wgs_ob_oracle_xa_one_phase";
String bqualStr = "bqual_test_wgs_ob_oracle_xa_one_phase";
Xid xid = new MysqlXid(gtridStr.getBytes(), bqualStr.getBytes(), 123);
try {
mysqlXAConnection.start(xid, XAResource.TMNOFLAGS);
// ps test
PreparedStatement pstmt = null;
ResultSet rs = null;
pstmt = conn.prepareStatement("select c1 from " + tableName2 + "");
rs = pstmt.executeQuery();
while (rs.next()) {
System.out.println(rs.getInt(1));
}
pstmt.close();
pstmt = conn.prepareStatement("insert into " + tableName2 + " (c1, c2) values(?, ?)");
pstmt.setInt(1, 12);
pstmt.setInt(2, 12);
pstmt.executeUpdate();
mysqlXAConnection.end(xid, XAResource.TMSUCCESS);
mysqlXAConnection.commit(xid, true);
} catch (Exception e) {
mysqlXAConnection.rollback(xid);
throw e;
}
}