package?classman;
import?db.dbconn;
import?util.stringUtil;
import?java.sql.Connection;
import?java.sql.PreparedStatement;
import?java.sql.Statement;
import?java.sql.ResultSet;
/**
?*?封裝對(duì)班級(jí)表的所有操作
?*?@author?鄧子云
?*/
public?class?class_operation{
???/**
????*?功能:往班級(jí)表增加一條記錄
????*?輸入?yún)?shù):class_name為班級(jí)名稱
????*?輸出:返回1表成功，返回2表數(shù)據(jù)連接參數(shù)配置不正確或連接數(shù)據(jù)庫(kù)失敗或數(shù)據(jù)庫(kù)操作失敗，
????*?返回3表此班級(jí)已存在，返回4表輸入?yún)?shù)class_name為空;
????*/
???public?int?class_add_one（String?class_name）{
???????dbconn?dbconnobject=new?dbconn（）;//數(shù)據(jù)庫(kù)連接對(duì)象
???????String?sqlString=null;//SQL語(yǔ)句字符串
???????ResultSet?rs=null;//結(jié)果記錄集
???????Connection?dbconn=dbconnobject.getDBConn（）;//得到數(shù)據(jù)庫(kù)連接
???????if（dbconn==null）?return?2;//連接失敗
???????//--------輸入?yún)?shù)不正確---------
???????if（class_name==null||class_name.trim（）.length（）==0）
??????????return?4;
???????//--------輸入?yún)?shù)編碼轉(zhuǎn)換-------
???????stringUtil?stringCode=new?stringUtil（）;
???????class_name=stringCode.codeToString（class_name.trim（））;
???????//--------插入記錄，先判斷是否已存在------
???????sqlString=“select?*?from?class?where?class_name=?“;
???????try{
??????????PreparedStatement?preSQLSelect=dbconn.prepareStatement（sqlString）;
??????????preSQLSelect.setString（1class_name）;
??????????rs=preSQLSelect.executeQuery（）;
??????????if（rs.next（））?return?3;//已存在此班級(jí)
??????????sqlString=“insert?into?class（class_name）?values（?）“;
??????????PreparedStatement?preSQLInsert=dbconn.prepareStatement（sqlString）;
??????????preSQLInsert.setString（1class_name）;
??????????preSQLInsert.executeUpdate（）;
??????????return?1;
????????}catch（Exception?e）{
??????????System.out.print（e）;
??????????return?2;
????????}?????????????
???}
???/**
????*?功能:查詢出所有的班級(jí)
????*?輸入?yún)?shù)：無(wú)
????*?輸出:所有班級(jí)的記錄集如果沒(méi)有記錄或操作失敗返回null
????*/
???public?ResultSet?class_select_all（）{
???????String?sqlString=null;//SQL語(yǔ)句字符串
???????Statement?sql=null;//SQL語(yǔ)句對(duì)象
???????ResultSet?rs=null;//結(jié)果記錄集
???????dbconn?dbconnobject=new?dbconn（）;//數(shù)據(jù)庫(kù)連接對(duì)象
???????Connection?dbconn=dbconnobject.getDBConn（）;//得到數(shù)據(jù)庫(kù)連接
???????if（dbconn==null）?return?null;//連接失敗
???????try{
??????????//-------查詢出數(shù)據(jù)------------
??????????sqlString=“select?*?from?class“;?
??????????sql=dbconn.createStatement（ResultSet.TYPE_SCROLL_SENSITIVE?ResultSet.CONCUR_READ_ONLY）;
??????????rs=sql.executeQuery（sqlString）;
??????????return?rs;
???????}catch（Exception?e）{
??????????System.out.print（e）;
??????????return?null;
???????}??
???}
???/**
????*?功能：刪除一個(gè)班級(jí)的信息
????*?輸入?yún)?shù)：班級(jí)的ID號(hào)
????*?輸出：返回1表成功，返回2表數(shù)據(jù)連接參數(shù)配置不正確或連接數(shù)據(jù)庫(kù)失敗，
????*?返回4表輸入?yún)?shù)class_id為0，即輸入?yún)?shù)不正確
????*/
???public?int?class_delete（int?class_id）{
???????String?sqlString=null;//SQL語(yǔ)句字符串
???????ResultSet?rs=null;//結(jié)果記錄集
???????dbconn?dbconnobject=new?dbconn（）;//數(shù)據(jù)庫(kù)連接對(duì)象
???????Connection?dbconn=dbconnobject.getDBConn（）;//得到數(shù)據(jù)庫(kù)連接
???????if（dbconn==null）?return?2;//連接失敗
???????if（class_id==0）?return?4;//輸入?yún)?shù)不正確
???????//---------刪除數(shù)據(jù)--------------
???????sqlString=“delete?from?class?where?class_id=?“;
???????try{
???????????PreparedStatement?preSQLDelete=dbco