Java connects to MySQL database and makes additional deletions and checks

1, the specific code implementation

Import java.sql.*;p Ublic class Databaseservice {/** * Create Connection * * @param dbtype * @param username * @param pas Sword * @param URL * @return * @throws Exception */public static Connection connectdbdriver (String dbtype, String username , string password, string url) throws Exception {Connection conn = null;try {if (dbtype.equals ("MySQL")) {Class.forName ("Co M.mysql.jdbc.driver "). newinstance ();} else if (dbtype.equals ("Oracle")) {Class.forName ("Oracle.jdbc.driver.OracleDriver"). newinstance ();} else {}conn = Drivermanager.getconnection (URL, username, password);} catch (Exception e) {e.printstacktrace ();} Return conn;} /** * Close DB * * @param conn * @throws Exception */public void Closedbdriver (Connection conn) throws Exception {try {Co Nn.close ();} catch (Exception e) {/* Ignore close errors */e.printstacktrace ();}} /** * Get ResultSet * * @param conn * @param SQL * @return * @throws Exception */private static ResultSet Getresultset (Co Nnection conn, String sql) throws Exception {ReSultset ResultSet = null;try {//PreparedStatement pstmt;//ResultSet rset;//arbitrary front and back scrolling; parameter set to read-only type statement statement = conn . createstatement (resultset.type_scroll_insensitive,resultset.concur_read_only);//pstmt = Conn.prepareStatement ( SQL); resultSet = statement.executequery (sql);} catch (Exception e) {e.printstacktrace ();} return resultSet;} /** * Get ColumnCount * * @param resultSet * @return * @throws Exception */private static int getColumnCount (ResultSet re  Sultset) throws Exception {int columnCount = 0;try {//ResultSet ResultSet = THIS.GETRESULTSET (conn, SQL);//getmetadata () Gets the number, type, and property of the column for this ResultSet object//getcolumncount () returns the number of columns in this ResultSet object. ColumnCount = Resultset.getmetadata (). getColumnCount (); if (ColumnCount = = 0) {}} catch (Exception e) {e.printstacktrace ( );} return columnCount;} /** * Get ColumnCount * * @param conn * @param SQL * @return * @throws Exception */public static int getColumnCount (Conne Ction conn, String sql) throws Exception {int columnCount = 0;try {//ResultSet RESultset = THIS.GETRESULTSET (conn, sql), ColumnCount = GETRESULTSET (conn, SQL). GetMetaData (). getColumnCount (); if ( ColumnCount = = 0) {}} catch (Exception e) {e.printstacktrace ();} return columnCount;} /** * Get RowCount * * @param conn * @param SQL * @return * @throws Exception */public int GetRowCount (Connection conn, S  Tring sql) throws Exception {int rowCount = 0;try {ResultSet ResultSet = getresultset (conn, SQL);//Booleanlast () move cursor to this The last line of the ResultSet object. Resultset.last ();//Booleanlast () moves the cursor to the last line of this ResultSet object. RowCount = Resultset.getrow (); if (RowCount = = 0) {}} catch (Exception e) {e.printstacktrace ();} return rowCount;} /** * Get RowCount * * @param resultSet * @return * @throws Exception */private static int GetRowCount (ResultSet Resultse T) throws Exception {int rowCount = 0;try {resultset.last (); rowCount = Resultset.getrow (); if (RowCount = = 0) {}} catch (Ex Ception e) {e.printstacktrace ();} return rowCount;} /** * Get data by row index and Col index * * @param conn * @param SQL *@param row * @param col * @return * @throws Exception */public static string GetData (Connection conn, String sql, int row, int col) throws Exception {String data = null;int RowNum = 0;int RowCount = 0;int ColCount = 0;try {ResultSet ResultSet = GETRESULTSET (conn, sql); ColCount = getColumnCount (resultSet); rowcount = GetRowCount (ResultSet);//beforefirst () Move the cursor to the beginning of this ResultSet object, just before the first line. Resultset.beforefirst (), if (RowCount > 0) {if (row <= 0 | | row > ROWCOUNT) {} else {if (col <= 0 | | col > C Olcount) {} else {while (Resultset.next ()) {rownum++;if (rownum = = row) {data = resultset.getstring (col); else {}} catch (Exception e) {e.printstacktrace ();} return data;} /** * Get data by row index and Col index * * @param conn * @param SQL * @param row * @param field * @return * @throws Ex Ception */public static string GetData (Connection conn, string sql, int row, string field) throws Exception {String data = Null;int rownum = 0;int rowcount = 0;//int colcount = 0;try {ReSultset ResultSet = getresultset (conn, SQL);//ColCount = getColumnCount (resultSet); rowcount = GetRowCount (ResultSet); Resultset.beforefirst (), if (RowCount > 0) {if (row <= 0 | | row > ROWCOUNT) {} else {while (Resultset.next ()) {row Num++;if (rownum = = row) {data = resultset.getstring (field); break;}}} else {}} catch (Exception e) {e.printstacktrace ();} return data;} The Executeupdate method can perform new, update, and delete three SQL statements public static int executeupdate (Connection conn, String sql) {Statement stmt = null; try {stmt = Conn.createstatement (); stmt.executeupdate (sql); int updatecount = Stmt.getupdatecount (); return Updatecount ;} catch (Exception e) {e.printstacktrace ();} finally {if (stmt! = null) {try {stmt.close ();} catch (SQLException e) {E.print StackTrace ();}}} return 0;}}

2, call the function to implement the deletion and modification

public class Jdbcdata {public     static void Main (string[] args) {        Connection Connection = databaseservice.connectd Bdriver ("MySQL", "username", "password", "URL");        String sql = "XXXX";        Query data, get to Data        String: Databaseservice.getdata (Connection, sql,1,1);        String sqlstatus = "XXXX";        Update Data        databaseservice.executeupdate (connection,sqlstatus);}     }

　　

Java connects to MySQL database and makes additional deletions and checks