网页在线聊天简易实现.

package datasource; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.util.ArrayList; import java.util.Calendar; import connection.Word; public class DatabaseManager { private Database database; public DatabaseManager() { this.database = new Database(); } @SuppressWarnings("finally") public String getKey(String name) { String key = ""; String sqlStr = "select * from tbUser where name = ?"; Connection conn = this.database.getConnection(); PreparedStatement ppStatement = this.database.getPreparedStatement(sqlStr,conn); try{ ppStatement.setString(1, name); ResultSet rs = ppStatement.executeQuery(); if(rs.next()) key = rs.getString("password"); rs.close(); ppStatement.close(); conn.close(); }catch(Exception e){ e.printStackTrace(); }finally{ return key.trim(); } } @SuppressWarnings("finally") public boolean isExit(String name) { boolean flag = false; Connection conn = this.database.getConnection(); PreparedStatement pps = this.database.getPreparedStatement("select * from tbUser where name = ?",conn); try{ pps.setString(1, name); ResultSet rs = pps.executeQuery(); if(rs.next()) flag = true; rs.close(); pps.close(); conn.close(); }catch(Exception e){ e.printStackTrace(); }finally{ return flag; } } @SuppressWarnings("finally") public ArrayList<String> getAllNames() { ArrayList<String> names = new ArrayList<String>(); Connection conn = this.database.getConnection(); PreparedStatement ppStatement = this.database.getPreparedStatement("select * from tbUser",conn); try{ ResultSet rs = ppStatement.executeQuery(); while(rs.next()) names.add(rs.getString("name")); rs.close(); ppStatement.close(); conn.close(); }catch(Exception e){ e.printStackTrace(); }finally{ return names; } } @SuppressWarnings("finally") public ArrayList<Word> getContent(String name) { ArrayList<Word> content = new ArrayList<Word>(); Connection conn = this.database.getConnection(); PreparedStatement pps = this.database.getPreparedStatement("select * from tbConnection where orignName = ? or targetName = ?",conn); try{ pps.setString(1, name); pps.setString(2, name); ResultSet rs = pps.executeQuery(); while(rs.next()) content.add(new Word(rs.getString("orignName"),rs.getString("targetName"),rs.getString("content"),rs.getTimestamp("date").toString())); rs.close(); pps.close(); conn.close(); }catch(Exception e){ e.printStackTrace(); }finally{ return content; } } @SuppressWarnings("finally") public ArrayList<Word> getContent(String name1,String name2) { ArrayList<Word> result = new ArrayList<Word>(); Connection conn = this.database.getConnection(); PreparedStatement pps = this.database.getPreparedStatement("select * from tbConnection where (orignName = ? and targetName = ?) or (orignName = ? and targetName = ?)",conn); try{ pps.setString(1, name1); pps.setString(2, name2); pps.setString(3, name2); pps.setString(4, name1); ResultSet rs = pps.executeQuery(); while(rs.next()) result.add(new Word(rs.getString("orignName"),rs.getString("targetName"),rs.getString("content"),rs.getTimestamp("date").toString())); rs.close(); pps.close(); conn.close(); }catch(Exception e){ e.printStackTrace(); }finally{ return result; } } @SuppressWarnings("finally") public boolean addUser(String name,String password) { boolean flag = false; if(this.isExit(name)) return flag; Connection conn = this.database.getConnection(); PreparedStatement pps = this.database.getPreparedStatement("insert into tbUser values(?,?)",conn); try{ pps.setString(1, name); pps.setString(2, password); if( pps.executeUpdate() != 0) flag = true; pps.close(); conn.close(); }catch(Exception e){ e.printStackTrace(); }finally{ return flag; } } public void removeUser(String name) { Connection conn = this.database.getConnection(); PreparedStatement pps = this.database.getPreparedStatement("delete from tbUser where name = ?",conn); try{ pps.setString(1, name); pps.executeUpdate(); pps.close(); conn.close(); }catch(Exception e){ e.printStackTrace(); } } public void addContent(String orign,String target,String content) { long id = this.getCount() + 1; Connection conn = this.database.getConnection(); PreparedStatement pps = this.database.getPreparedStatement("insert into tbConnection values(?,?,?,?,?)",conn); try{ pps.setLong(1, id); pps.setString(2, orign); pps.setString(3, target); pps.setString(4, content); pps.setString(5, this.getSystemTime()); pps.executeUpdate(); pps.close(); conn.close(); }catch(Exception e){ e.printStackTrace(); } } @SuppressWarnings("finally") public long getCount() { long result = 0; Connection conn = this.database.getConnection(); PreparedStatement pps = this.database.getPreparedStatement("select max(id) as id from tbConnection",conn); try{ ResultSet rs = pps.executeQuery(); if(rs.next()) result = rs.getLong("id"); rs.close(); pps.close(); conn.close(); }catch(Exception e){ e.printStackTrace(); }finally{ return result; } } private String getSystemTime() { Calendar c = Calendar.getInstance(); String date = String.valueOf(c.get(Calendar.YEAR)) + String.valueOf(c.get(Calendar.MONTH)) + String.valueOf(c.get(Calendar.DATE)) + String.valueOf(c.get(Calendar.HOUR)) + String.valueOf(c.get(Calendar.MINUTE)) + String.valueOf(c.get(Calendar.SECOND)); return date; } }