简单的JAVA连接数据库的增删改查操作

package com.asiasoft.studentsmanager; import java.util.ArrayList; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.sql.*; import com.asiasoft.studentsmanager.utils.MyDBUtil; public class StudentsManger { public static void main(String[] args) throws ClassNotFoundException, SQLException, IOException { InputStreamReader input1 = new InputStreamReader(System.in); BufferedReader br1 = new BufferedReader(input1); String isContinue = ""; String uname=""; String pword=""; int loginTimes = 3; boolean isTOK = false; Student s = new Student(); System.out.println("****************"); System.out.println("**欢迎登陆学员管理系统**"); System.out.println("****************"); /*while (loginTimes > 0) { try { System.out.println("请输入用户名："); uname = br.readLine(); System.out.println("请输入密码："); pword = br.readLine(); t1.setTcode(uname); t1.setTname(pword); if (Tlogin(t1)) { isTOK = true; break; }else { loginTimes--; if (loginTimes > 0) { System.out.println("账号或密码错误，是否重新输入（y/n）?"); isContinue = br1.readLine(); if ("n".equalsIgnoreCase(isContinue)) { break; } } } } catch (IOException e) { e.printStackTrace(); } }*/ display(); } public static void display() throws ClassNotFoundException, SQLException, IOException { String operater = ""; int id; String uname; String pword; String email; InputStreamReader input = new InputStreamReader(System.in); BufferedReader br = new BufferedReader(input); Connection con = MyDBUtil.getConnection(); /*Statement st = con.createStatement(); ResultSet rs = st.executeQuery("select * from students");*/ String sql = "select * from students"; Statement st = MyDBUtil.getStatement(con); ResultSet rs = MyDBUtil.getResultSet(st, sql); System.out.println("id\t|uname\t|pword\t|email\t"); while(rs.next()){ System.out.println(rs.getString("id")+"\t|" +rs.getString("uname")+"\t|"+ rs.getString("pword")+"\t|"+ rs.getString("email")+"\t");} System.out.println("********************"); System.out.println("*增加学生信息 输入add； *"); System.out.println("*删除学生信息 输入delete； *"); System.out.println("*修改学生信息 输入update； *"); System.out.println("*查询学生信息 输入query； *"); System.out.println("*退出请输入exit； *"); System.out.println("********************"); operater = br.readLine(); if("add".equalsIgnoreCase(operater)){ //add System.out.print("请输入要添加的姓名："); uname = br.readLine(); System.out.print("请输入要添加的密码："); pword = br.readLine(); System.out.print("请输入要添加的邮箱："); email = br.readLine(); Student s = new Student(); s.setUname(uname); s.setPword(pword); s.setEmail(email); String addsql = "insert into students (uname,pword,email) values('"+uname+"','"+pword+"','"+email+"')"; int addresult = st.executeUpdate(addsql); System.out.println("添加成功！"); display(); }else if("delete".equalsIgnoreCase(operater)){ //shanchu System.out.println("请输入将要删除的编号："); id = Integer.parseInt(br.readLine()); String deletesql = "delete from students where id='"+id+"'"; int deleteResult = st.executeUpdate(deletesql); System.out.println("删除成功！"); display(); }else if("update".equalsIgnoreCase(operater)){ //update System.out.println("请输入你所要修改的编号："); id = Integer.parseInt(br.readLine()); System.out.println("请输入修改后的名字："); uname = br.readLine(); System.out.println("请输入修改后的密码："); pword = br.readLine(); System.out.println("请输入修改后的邮箱："); email = br.readLine(); String updatesql = "update students set uname='"+uname+"',pword='"+pword+"',email='"+email+"' where id = '"+id+"'"; int updateResult = st.executeUpdate(updatesql); System.out.println("修改成功！"); display(); }else if("query".equalsIgnoreCase(operater)){ //query System.out.println("请输入要查询的编号："); id = Integer.parseInt(br.readLine()); String querysql = "select * from students where id = '"+id+"'"; rs = st.executeQuery(querysql); /*while(rs.next()){ int k = Integer.parseInt(rs.getString("id")); if(k!= id){ System.out.println("查无此人！"); break; }else{ continue; } }*/ System.out.println("id\t|uname\t|pword\t|email\t"); while(rs.next()){ System.out.println(rs.getString("id")+"\t|" +rs.getString("uname")+"\t|"+ rs.getString("pword")+"\t|"+ rs.getString("email")+"\t|"); } System.out.println("查询完毕！"); System.out.println("是否继续使用本系统？（y/n）"); String j = br.readLine(); if("y".equalsIgnoreCase(j)){ display(); }else{ System.out.println("谢谢你的使用！"); } }else if("exit".equalsIgnoreCase(operater)){ System.out.println("谢谢你的使用！！"); } } }