Question

这段java程序怎么解释？ 急急急！今天11：40要交作业，把我的悬赏分都发出去！！！

要每块每块的解释！ 详细点！快啊
package crm.order;

import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.jsp.*;
import java.sql.*;
import java.io.*;
import include.nseer_db.*;
//调用java包

public class delete_ok extends HttpServlet {
/*delete_ok 继承了HttpServlet了 功能
ServletContext application;
HttpSession session;
nseer_db_backup1 erp_db = null;

public synchronized void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
HttpSession dbSession = request.getSession();
JspFactory _jspxFactory = JspFactory.getDefaultFactory();
PageContext pageContext = _jspxFactory.getPageContext(this, request, response, "", true, 8192, true);
ServletContext dbApplication = dbSession.getServletContext();
try {
nseer_db_backup1 crm_db = new nseer_db_backup1(dbApplication);
PrintWriter out = response.getWriter();
if (crm_db.conn((String) dbSession.getAttribute("unit_db_name"))) {
String id = request.getParameter("id");
String order_ID = "";
try {
String sql = "select * from crm_order where id='" + id + "'";
ResultSet rs = crm_db.executeQuery(sql);
if (rs.next()) {
order_ID = rs.getString("order_ID");
}
String sql1 = "delete from crm_order_details where order_ID='" + order_ID + "'";
crm_db.executeUpdate(sql1);
String sql2 = "delete from crm_order where id='" + id + "'";
crm_db.executeUpdate(sql2);
} catch (Exception ex) {
out.println("error" + ex);
}
crm_db.commit();
crm_db.close();
response.sendRedirect("crm/order/delete_list.jsp");
} else {
response.sendRedirect("error_conn.htm");
}
} catch (Exception ex) {
}
}

Answer 1

package crm.order;

import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.jsp.*;
import java.sql.*;
import java.io.*;
import include.nseer_db.*;
//调用java包

public class delete_ok extends HttpServlet { //继承HttpServlet类
/*delete_ok 继承了HttpServlet了 功能
ServletContext application; //上下问配置类
HttpSession session; //Http的会话
nseer_db_backup1 erp_db = null;

public synchronized void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
HttpSession dbSession = request.getSession(); //获取当前的会话
JspFactory _jspxFactory = JspFactory.getDefaultFactory(); //获取jsp的工厂类
PageContext pageContext = _jspxFactory.getPageContext(this, request, response, "", true, 8192, true); //获取上下文配置信息
ServletContext dbApplication = dbSession.getServletContext(); //这个应该是获取数据的配置信息
try {
nseer_db_backup1 crm_db = new nseer_db_backup1(dbApplication); //这个应该是连接数据库
PrintWriter out = response.getWriter();//获取 PrintWriter
if (crm_db.conn((String) dbSession.getAttribute("unit_db_name"))) { //判断 如果连接上数据库 就执行里面的操作
String id = request.getParameter("id"); //获取上个页面中传过来的ID
String order_ID = "";
try {
String sql = "select * from crm_order where id='" + id + "'"; //查询的sql语句
ResultSet rs = crm_db.executeQuery(sql);//发送到数据端执行
if (rs.next()) {//如果返回结果中有数据 执行括号里的内容
order_ID = rs.getString("order_ID"); //获取ID值
}
String sql1 = "delete from crm_order_details where order_ID='" + order_ID + "'";//在表crm_order_details 中删除等于order_ID的信息
crm_db.executeUpdate(sql1);//执行删除操作
String sql2 = "delete from crm_order where id='" + id + "'";//删除等于ID的记录
crm_db.executeUpdate(sql2);//执行删除操作
} catch (Exception ex) {//如果try里面执行有错误 就执行catch里面的信息
out.println("error" + ex); //打印错误信息
}
crm_db.commit();//数据库提交
crm_db.close();//关闭数据库
response.sendRedirect("crm/order/delete_list.jsp"); //跳转到delete_list.jsp页面
} else {
response.sendRedirect("error_conn.htm");
}
} catch (Exception ex) {
}
}
很详细了哈 希望能够帮到你