我得到了代码，我必须让它做其他事情。当我去编译我的 servlet 时，它无法识别我的 bean。我已经从所有不同的目录中删除、重新编译和尝试。我不知道为什么这不起作用。
import BH.*;
import java.io.IOException;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
import java.util.function.*;
import static java.util.Arrays.asList;
import java.text.DateFormat;
import java.util.concurrent.locks.ReentrantLock;
import java.util.Random;
public class sessionServlet extends HttpServlet {
private List<String[]> the_sessions;
private DateFormat df;
public static ReentrantLock thelock = new ReentrantLock();
public void init() throws ServletException {
the_sessions=new ArrayList<String[]>();
df=DateFormat.getDateTimeInstance(DateFormat.LONG,DateFormat.LONG);
}
protected void doGet(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException
{
if ((!(req.getParameter("task")==null))&&(req.getParameter("task").trim().equals("deploy"))) {
PrintWriter out = res.getWriter();
out.println("<html>");
out.println("<body>");
out.println("<hr /><center><h1>sessionServlet Deployed</h1></center><hr />");
out.println("</body>");
out.println("</html>");
return;
}
Consumer <String> forwardTo =(s) ->ForwardTo(s,req,res);
boolean is_first_visit=true;
String[] this_session=new String[3];
String manager = req.getParameter("manager");
for (String [] a_session :the_sessions) {
if (a_session[0].equals(manager)) { //Found an active session
is_first_visit=false;
this_session=a_session;
break;
}
}
if ((req.getParameter("task")==null)&&(!is_first_visit)) {
the_sessions.remove(this_session);
is_first_visit=true; // just used http://hoare.cs.umsl.edu/servlet/js_test/sessionServlet
}
req.setAttribute("thesessioncount",the_sessions.size());
if (is_first_visit) {
if (the_sessions.size()==10) {
forwardTo.accept("noSessions.jsp"); //No Available Sessions
return;
}
String randomStr = getRandomString();
String[] new_session = {randomStr,df.format(new Date()),"need a name"};
the_sessions.add(new_session);
this_session=new_session;
req.setAttribute("manager",randomStr);
forwardTo.accept("startSession.jsp");
return;
}
String the_name="";
String the_pw="";
if (this_session[2].equals("need a name")) { //No name given yet
the_name=req.getParameter("whoisit");
the_pw=req.getParameter("passwd");
if ((the_name==null)||(the_name.trim().length()==0)||checkPW(the_name,the_pw)) { //checkPW returns false if correct
the_sessions.remove(this_session);
req.setAttribute("thesessioncount",the_sessions.size());
forwardTo.accept("startSession.jsp");
return; // didn't enter a name in startSession
}
}
this_session[2]=the_name.trim();
req.setAttribute("thename", this_session[2]);
if (tooLong(this_session[1],df.format(new Date()))) { //Has the session timed out?
the_sessions.remove(this_session);
forwardTo.accept("Expired.jsp");
return;
} else {
this_session[1]=df.format(new Date()); //reset the last session activity time
NotesBean thesenotes=new NotesBean();
if(req.getParameter("task").trim().equals("9")){
the_sessions.remove(this_session);
forwardTo.accept("exit.jsp");
return;
}
thelock.lock();
if (!req.getParameter("task").trim().equals("0")) { //add ACC here, also show/update posts
thesenotes.setAll(req.getParameter("java_source"),Integer.parseInt(req.getParameter("version")));
if (req.getParameter("task").trim().equals("2")) {
thesenotes.setNotes(req.getParameter("notes"),req.getParameter("java_source"),Integer.parseInt(req.getParameter("version")));
}
}
req.setAttribute("thesessioncount",the_sessions.size());
req.setAttribute("theBean",thesenotes);
req.setAttribute("manager",manager);
//req.setAttribute("theURL", "http://www.umsl.edu/~siegelj/turing.jpg");
forwardTo.accept("getNotes.jsp");
thelock.unlock();
return;
}
}//end doGet
boolean tooLong(String now,String then){
//Check amount of time that passed
return false;
}
boolean checkPW(String name,String password){
AccountBean theAccount = new AccountBean();
theAccount.setAccount(name);
if(theAccount.isPassword(password))
return false;
return true;
}
public void log(String s){
FileWriter fileWriter = null;
try {
String content =s+" at :"+new Date(System.currentTimeMillis()).toString()+"\n";
File theLogFile = new File("C:/Tomcat/webapps/js_test/session.log");
fileWriter = new FileWriter(theLogFile,true);
fileWriter.write(content);
} catch (IOException ex) {
} finally {
try {
fileWriter.close();
} catch (IOException ex) {
}
}
}
void ForwardTo(String s,HttpServletRequest req, HttpServletResponse res)
{
RequestDispatcher rd= req.getRequestDispatcher(s);
try {
rd.forward(req, res);
} catch (IOException|ServletException is) {
log(" req from "+s+" not forwarded at ");
try {
throw is;
} catch (Exception e) {
}
}
}
public void destroy()
{
log("The instance was destroyed");
}
public String getRandomString(){
byte[] randbyte=new byte[10];
Random rand = new Random(System.currentTimeMillis());
for (int idx = 0; idx <10; ++idx) {
int randomInt = rand.nextInt(26); //0<=randomInt<26
//System.out.println(randomInt);
randbyte[idx]=(byte)(randomInt+65);
}
try {
String rs=new String(randbyte, "UTF-8");
//System.out.println(rs);
return rs;
} catch (Exception e) {
//System.out.println("bad string");
return "bad";
}
}
}
AccountBean.java
package mybeans;
import BH.*;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;
import java.util.ArrayList;
import java.util.Arrays;
import static java.util.Arrays.asList;
import java.sql.*;
public class AccountBean implements java.io.Serializable {
static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";
static final String DB_URL = "jdbc:mysql://localhost/cs4010";
static final String USER = "cs4010";
static final String PASS = "cs4010";
private String account="";
private String password="";
public AccountBean(){
}
public void setAccount(String a)
{
account = a;
}
public String getAccount()
{
return account;
}
public void setPassword(String p)
{
password = p;
}
public String getPassword(){
return password;
}
public void createAccount()
{
try {
Class.forName("com.mysql.jdbc.Driver");
Connection conn = DriverManager.getConnection(DB_URL,USER,PASS);
Statement stmt = conn.createStatement();
// System.out.println("here: "+Bytes_Hex.String2HexString(n));
String this_query="INSERT INTO ries_userpass (username, password) VALUES ("+account+","+password+");";
// System.out.println(this_query);
stmt.executeUpdate(this_query);
stmt.close();
conn.close();
} catch (Exception e) {
}
return ;
}
public boolean isPassword(String p) //make this to use
{
try {
Class.forName("com.mysql.jdbc.Driver");
Connection conn = DriverManager.getConnection(DB_URL,USER,PASS);
Statement stmt = conn.createStatement();
String this_query=" SELECT * from ries_userpass WHERE username="+account+";";
ResultSet rs = stmt.executeQuery(this_query);
while (rs.next()) {
password=Bytes_Hex.HexString2String(rs.getString("posts"));
if(password.equals(p))
{
rs.close();
stmt.close();
conn.close();
return true;
}
}
rs.close();
stmt.close();
conn.close();
}
catch (Exception e) {
return false;
}
return false;
}
}
最佳答案
添加此语句 import mybeans.*;，因为您正在使用 AccountBean 但您没有导入该类包；
import BH.*;
import mybeans.*;
import java.io.IOException;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
import java.util.function.*;
import static java.util.Arrays.asList;
import java.text.DateFormat;
import java.util.concurrent.locks.ReentrantLock;
import java.util.Random;
public class sessionServlet extends HttpServlet {
private List<String[]> the_sessions;
private DateFormat df;
public static ReentrantLock thelock = new ReentrantLock();
public void init() throws ServletException {
the_sessions=new ArrayList<String[]>();
df=DateFormat.getDateTimeInstance(DateFormat.LONG,DateFormat.LONG);
}
protected void doGet(HttpServletRequest req, HttpServletResponse res)
throws ServletException, IOException
{
if ((!(req.getParameter("task")==null))&&(req.getParameter("task").trim().equals("deploy"))) {
PrintWriter out = res.getWriter();
out.println("<html>");
out.println("<body>");
out.println("<hr /><center><h1>sessionServlet Deployed</h1></center><hr />");
out.println("</body>");
out.println("</html>");
return;
}
Consumer <String> forwardTo =(s) ->ForwardTo(s,req,res);
boolean is_first_visit=true;
String[] this_session=new String[3];
String manager = req.getParameter("manager");
for (String [] a_session :the_sessions) {
if (a_session[0].equals(manager)) { //Found an active session
is_first_visit=false;
this_session=a_session;
break;
}
}
if ((req.getParameter("task")==null)&&(!is_first_visit)) {
the_sessions.remove(this_session);
is_first_visit=true; // just used http://hoare.cs.umsl.edu/servlet/js_test/sessionServlet
}
req.setAttribute("thesessioncount",the_sessions.size());
if (is_first_visit) {
if (the_sessions.size()==10) {
forwardTo.accept("noSessions.jsp"); //No Available Sessions
return;
}
String randomStr = getRandomString();
String[] new_session = {randomStr,df.format(new Date()),"need a name"};
the_sessions.add(new_session);
this_session=new_session;
req.setAttribute("manager",randomStr);
forwardTo.accept("startSession.jsp");
return;
}
String the_name="";
String the_pw="";
if (this_session[2].equals("need a name")) { //No name given yet
the_name=req.getParameter("whoisit");
the_pw=req.getParameter("passwd");
if ((the_name==null)||(the_name.trim().length()==0)||checkPW(the_name,the_pw)) { //checkPW returns false if correct
the_sessions.remove(this_session);
req.setAttribute("thesessioncount",the_sessions.size());
forwardTo.accept("startSession.jsp");
return; // didn't enter a name in startSession
}
}
this_session[2]=the_name.trim();
req.setAttribute("thename", this_session[2]);
if (tooLong(this_session[1],df.format(new Date()))) { //Has the session timed out?
the_sessions.remove(this_session);
forwardTo.accept("Expired.jsp");
return;
} else {
this_session[1]=df.format(new Date()); //reset the last session activity time
NotesBean thesenotes=new NotesBean();
if(req.getParameter("task").trim().equals("9")){
the_sessions.remove(this_session);
forwardTo.accept("exit.jsp");
return;
}
thelock.lock();
if (!req.getParameter("task").trim().equals("0")) { //add ACC here, also show/update posts
thesenotes.setAll(req.getParameter("java_source"),Integer.parseInt(req.getParameter("version")));
if (req.getParameter("task").trim().equals("2")) {
thesenotes.setNotes(req.getParameter("notes"),req.getParameter("java_source"),Integer.parseInt(req.getParameter("version")));
}
}
req.setAttribute("thesessioncount",the_sessions.size());
req.setAttribute("theBean",thesenotes);
req.setAttribute("manager",manager);
//req.setAttribute("theURL", "http://www.umsl.edu/~siegelj/turing.jpg");
forwardTo.accept("getNotes.jsp");
thelock.unlock();
return;
}
}//end doGet
boolean tooLong(String now,String then){
//Check amount of time that passed
return false;
}
boolean checkPW(String name,String password){
AccountBean theAccount = new AccountBean();
theAccount.setAccount(name);
if(theAccount.isPassword(password))
return false;
return true;
}
public void log(String s){
FileWriter fileWriter = null;
try {
String content =s+" at :"+new Date(System.currentTimeMillis()).toString()+"\n";
File theLogFile = new File("C:/Tomcat/webapps/js_test/session.log");
fileWriter = new FileWriter(theLogFile,true);
fileWriter.write(content);
} catch (IOException ex) {
} finally {
try {
fileWriter.close();
} catch (IOException ex) {
}
}
}
void ForwardTo(String s,HttpServletRequest req, HttpServletResponse res)
{
RequestDispatcher rd= req.getRequestDispatcher(s);
try {
rd.forward(req, res);
} catch (IOException|ServletException is) {
log(" req from "+s+" not forwarded at ");
try {
throw is;
} catch (Exception e) {
}
}
}
public void destroy()
{
log("The instance was destroyed");
}
public String getRandomString(){
byte[] randbyte=new byte[10];
Random rand = new Random(System.currentTimeMillis());
for (int idx = 0; idx <10; ++idx) {
int randomInt = rand.nextInt(26); //0<=randomInt<26
//System.out.println(randomInt);
randbyte[idx]=(byte)(randomInt+65);
}
try {
String rs=new String(randbyte, "UTF-8");
//System.out.println(rs);
return rs;
} catch (Exception e) {
//System.out.println("bad string");
return "bad";
}
}
}
关于java - 错误 : cannot find symbol, 找不到我的 bean，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/43564345/