Basic jdbc Learning

Package study; import java. SQL. *; import java. util. required; // public class StudyJdbc {// public static void main (String [] args) {// Connection conn = null; // Statement st = null; // ResultSet rs = null; // try {// Class. forName ("org. gjt. mm. mysql. driver "); // conn = DriverManager. getConnection (// "jdbc: mysql: // localhost: 3306/fly", "root", ""); // st = conn. createStatement (); // rs = st.exe cuteQuery ("select * from m Essage "); // while (rs. next () // System. out. println (rs. getInt ("id") + ":" // + rs. getString ("content"); //} catch (ClassNotFoundException e) {// e. printStackTrace (); // write it to the error log //} catch (SQLException e) {// e. printStackTrace (); //} finally {// try {// if (rs! = Null) // rs. close (); // if (st! = Null) // st. close (); // if (conn! = Null) // conn. close (); //} catch (SQLException e) {// e. printStackTrace (); /// // check the database content in eclipse // public class StudyJdbc {// PreparedStatment, filter some special characters to eliminate SQL injection and improve efficiency // public static void main (String [] args) {// Connection conn = null; // PreparedStatement st = null; // try {// Class. forName ("org. gjt. mm. mysql. driver "); // conn = DriverManager. getConnection (// "jdbc: mysql: // localhost: 3306/fly ", "Root", ""); // st = conn. prepareStatement ("insert into message values (null ,?, Current_timestamp )");//? Placeholder /// select * from message where id =? And content =? // St. setString (1, "hello"); // st.exe cuteUpdate (); //} catch (ClassNotFoundException e) {// e. printStackTrace (); // write it to the error log //} catch (SQLException e) {// e. printStackTrace (); //} finally {// try {// if (st! = Null) // st. close (); // if (conn! = Null) // conn. close (); //} catch (SQLException e) {// e. printStackTrace (); ///} // view the database content in eclipse // public class StudyJdbc {// batch processing // public static void main (String [] args) {// Connection conn = null; // PreparedStatement st = null; // try {// Class. forName ("org. gjt. mm. mysql. driver "); // conn = DriverManager. getConnection (// "jdbc: mysql: // localhost: 3306/fly", "root", ""); // st = conn. prepareStatement ("Insert into message values (null ,?, Current_timestamp )");//? Placeholder /// st. setString (1, "batch processing 1"); // st. addBatch (); // st. setString (1, "Batch Processing 2"); // st. addBatch (); // st. setString (1, "batch processing 3"); // st. addBatch (); // st.exe cuteBatch (); // when inserting three items together //} catch (ClassNotFoundException e) {/e. printStackTrace (); // write it to the error log //} catch (SQLException e) {// e. printStackTrace (); //} finally {// try {// if (st! = Null) // st. close (); // if (conn! = Null) // conn. close (); //} catch (SQLException e) {// e. printStackTrace (); ///} // view the database content in eclipse // public class StudyJdbc {// transaction processing // public static void main (String [] args) {// Connection conn = null; // PreparedStatement st = null; // try {// Class. forName ("org. gjt. mm. mysql. driver "); // conn = DriverManager. getConnection (// "jdbc: mysql: // localhost: 3306/fly", "root", ""); // conn. setAutoCommit (fa Lse); // automatically submit by default /// st = conn. prepareStatement ("insert into message values (null ,?, Current_timestamp )");//? Placeholder /// st. setString (1, "batch processing 1"); // st. addBatch (); // st. setString (1, "Batch Processing 2"); // st. addBatch (); // st. setString (1, "batch processing 3"); // st. addBatch (); // st.exe cuteBatch (); // three items are inserted together at the time of insertion. // conn. commit (); // confirm submission // conn. setAutoCommit (true); // restore automatic submission //} catch (ClassNotFoundException e) {// e. printStackTrace (); // write it to the error log //} catch (SQLException e) {// e. printStackTrace (); // try {// if (conn! = Null) // {// conn. rollback (); // roll back when an error occurs // conn. setAutoCommit (true); //} // catch (SQLException e1) // {// e1.printStackTrace (); ///} //} finally {// try {// if (st! = Null) // st. close (); // if (conn! = Null) // conn. close (); //} catch (SQLException e) {// e. printStackTrace (); ///} // view the database content in eclipse // public class StudyJdbc {// the handling process can be triggered. result set // public static void main (String [] args) {// Connection conn = null; // Statement st = null; // ResultSet rs = null; // try {// Class. forName ("org. gjt. mm. mysql. driver "); // conn = DriverManager. getConnection (// "jdbc: mysql: // localhost: 3306/fly", "root", ""); // required The number of lower keys supported by the development package and set/st = conn. createStatement (ResultSet. TYPE_SCROLL_INSENSITIVE, ResultSet. CONCUR_READ_ONLY); // only available, cannot update // rs1_st.exe cuteQuery ("select * from message"); // rs. next (); // if the preceding two values are not specified, only rs can be used. next (); // System. out. println (rs. getInt ("id"); // rs. last (); // System. out. println (rs. getInt ("id"); // rs. previous (); // rs. absolute (8); //} catch (ClassNotFoundException e) {// e. printStackTrace (); // write it to the error log //} c Atch (SQLException e) {// e. printStackTrace (); //} finally {// try {// if (st! = Null) // st. close (); // if (conn! = Null) // conn. close (); //} catch (SQLException e) {// e. printStackTrace (); ///} // view the database content in eclipse // public class StudyJdbc {// The processing can be updated result set // public static void main (String [] args) {// Connection conn = null; // Statement st = null; // ResultSet rs = null; // try {// Class. forName ("org. gjt. mm. mysql. driver "); // conn = DriverManager. getConnection (// "jdbc: mysql: // localhost: 3306/fly", "root", ""); // required The number of lower keys supported by the development package and set/st = conn. createStatement (ResultSet. TYPE_SCROLL_INSENSITIVE, ResultSet. CONCUR_UPDATABLE); // only available, updatable // rs1_st.exe cuteQuery ("select * from message"); // rs. next (); // if the preceding two values are not specified, only rs can be used. next (); // update a row of Data // rs. updateString ("content", "updatable"); // updates data in the memory // rs. updateRow (); // update the database content ///// Insert a new row // rs. moveToInsertRow (); // rs. updateString ("content", "AAAA"); // rs. insertRow (); // move the cursor to the new row // rs. moveToInsertR Ow (); // Delete rows // rs. absolute (3); // rs. deleteRow (); //} catch (ClassNotFoundException e) {// e. printStackTrace (); // write it to the error log //} catch (SQLException e) {// e. printStackTrace (); //} finally {// try {// if (st! = Null) // st. close (); // if (conn! = Null) // conn. close (); //} catch (SQLException e) {// e. printStackTrace (); //} // view the database content in eclipse //}