JAVA课程设计，学生管理系统，设计SQL server数据库操作

package 学生信息管理系统; import java.sql.*; public class Query { Object a[][]=null; String b[]=null; String tableName=""; int 字段个数; public Query(){ try{ Class.forName("com.microsoft.sqlserver.jdbc.SQLServerDriver"); } catch(ClassNotFoundException e){ System.out.println(e); } } public Object[][] getRecord(){//求表格的表头内容 a=null; b=null; Connection con; Statement sql; ResultSet rs; try{ String url; url="jdbc:sqlserver://localhost:1433;DatabaseName=Student"; con=DriverManager.getConnection(url,"ast","123456"); int 字段个数=getZiDuan(); int n=getAmount(); a=new Object[n][字段个数]; sql=con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_READ_ONLY); rs=sql.executeQuery("select * from "+tableName); int m=0; while(rs.next()){ for(int k=1;k<=字段个数;k++){ a[m][k-1]=rs.getString(k); }//获取了表格的表头内容 System.out.println(); m++; } con.close(); } catch(SQLException e){ System.out.println("请输入正确的表名"+e); } return a; } public int getAmount(){//求表内容有多少行 Connection con; Statement sql; ResultSet rs; try{ String url; url="jdbc:sqlserver://localhost:1433;DatabaseName=Student"; con=DriverManager.getConnection(url,"ast","123456"); sql=con.createStatement(ResultSet.TYPE_SCROLL_SENSITIVE,ResultSet.CONCUR_READ_ONLY); rs=sql.executeQuery("select * from "+tableName); rs.last();//获取匹配元素集合中最后一个元素。 int rows=rs.getRow(); return rows; } catch(SQLException exp){ System.out.println(""+exp); return 0; } } public String[] getField(){//求字段名称 Connection con; try{ String url; url="jdbc:sqlserver://localhost:1433;DatabaseName=Student"; con=DriverManager.getConnection(url,"ast","123456"); DatabaseMetaData metadata=con.getMetaData(); ResultSet rs1=metadata.getColumns(null, null, tableName, null); int 字段个数=getZiDuan(); b=new String[字段个数]; int k=0; while(rs1.next()){ b[k]=rs1.getString(4); //以String 的形式获取此 ResultSet 对象的当前行中指定列的值。 k++; } con.close(); } catch(SQLException e){ System.out.println(e); } return b; } public void setTableName(String s){//初始表名 tableName=s.trim(); } public int getZiDuan(){//求字段个数 Connection con; try{ String url; url="jdbc:sqlserver://localhost:1433;DatabaseName=Student"; con=DriverManager.getConnection(url,"ast","123456"); DatabaseMetaData metadata=con.getMetaData(); //得到此对象实例 ResultSet rs1=metadata.getColumns(null, null, tableName, null); //数据库连接通过getcolumns（）函数获取表字段信息 字段个数=0; while(rs1.next()) 字段个数++; } catch(SQLException e){ System.out.println(e); } return 字段个数; } }