[Java] java使用三层架构实现电影购票系统

import java.lang.reflect.field;
import java.sql.connection;
import java.sql.drivermanager;
import java.sql.preparedstatement;
import java.sql.resultset;
import java.sql.resultsetmetadata;
import java.sql.sqlexception;
import java.util.arraylist;
import java.util.list;
 
public class basedao {
 
 public static final string driver = "com.mysql.jdbc.driver";
 public static final string url = "jdbc:mysql://localhost:3306/tickets";
 
 // 加载驱动，只需加载一次
 static {
 try {
 class.forname(driver);
 } catch (classnotfoundexception e) {
 // todo auto-generated catch block
 e.printstacktrace();
 }
 }
 
 // 获得连接
 public connection getconn() {
 connection conn = null;
 
 try {
 conn = drivermanager.getconnection(url, "root", "123456");
 } catch (sqlexception e) {
 // todo auto-generated catch block
 e.printstacktrace();
 }
 return conn;
 }
 
 // 关闭所有
 public void releaseall(resultset rs, preparedstatement pstmt, connection conn) {
 
 try {
 if (rs != null) {
 rs.close();
 }
 if (pstmt != null) {
 pstmt.close();
 }
 if (conn != null) {
 conn.close();
 }
 } catch (sqlexception e) {
 // todo auto-generated catch block
 e.printstacktrace();
 }
 
 }
 
 // 增删改 封装
 public boolean operupdate(string sql, list<object> params) {
 connection conn = null;
 preparedstatement pstmt = null;
 int res = 0;
 
 // 获得与数据库的连接对象
 conn = getconn();
 
 try {
 
 pstmt = conn.preparestatement(sql);
 
 if (params != null) {
 for (int i = 0; i < params.size(); i++) {
 
 pstmt.setobject(i + 1, params.get(i));
 
 }
 
 }
 // 增刪改的統一方法
 
 res = pstmt.executeupdate();
 //返回的是sql在数据库中影响的行数
 } catch (sqlexception e) {
 // todo auto-generated catch block
 e.printstacktrace();
 } finally {
 releaseall(null, pstmt, conn);
 }
 
 return res > 0 ? true : false;
 
 }
 
 public <t> list<t> operquery(string sql, list<object> params, class<t> cls) throws exception {
 connection conn = null;
 preparedstatement pstmt = null;
 resultset rs = null;
 list<t> list = new arraylist<t>();
 conn = getconn();
 
 try {
 pstmt = conn.preparestatement(sql);
 
 if (params != null) {
 for (int i = 0; i < params.size(); i++) {
 
 pstmt.setobject(i + 1, params.get(i));
 
 }
 
 }
 // 增刪改的統一方法
 
 rs = pstmt.executequery();
 resultsetmetadata rsmd = rs.getmetadata();
 while (rs.next()) {
 t m = cls.newinstance();
 
 for (int i = 0; i < rsmd.getcolumncount(); i++) {
 string col_name = rsmd.getcolumnname(i + 1);
 
 object value = rs.getobject(col_name);
 
 field field;
 
 field = cls.getdeclaredfield(col_name);
 
 field.setaccessible(true);
 field.set(m, value);
 }
 list.add(m);
 }
 }
 
 catch (sqlexception e) {
 // todo auto-generated catch block
 e.printstacktrace();
 } finally {
 releaseall(rs, pstmt, conn);
 }
 return list;
 
 }
 
}