在IDEA中项目使用Ant打包报错
报错如下：
at org.apache.tools.ant.taskdefs.Javac.compile(Javac.java:1365)
at org.apache.tools.ant.taskdefs.Javac.execute(Javac.java:1070)
at org.apache.tools.ant.UnknownElement.execute(U...

u Ant 的下载 
Ant 是一个开源、免费的软件，可以从以下地址下载最新版本： 
http://ant.apache.org/ 
u Ant 的安装和配置 
Ant 的安装程序是一个压缩文件，例如最新版本的 Ant 1.6.5 安装程序文件名...
HTTP Status 500 - rnrn--------------------------------------------------------------------------------rnrntype Exception reportrnrnmessage rnrndescription The server encountered an internal error () that prevented it from fulfilling this request.rnrnexception rnrnorg.apache.jasper.JasperException: Exception in JSP: /Jsp/dtree/Bbs.jsp:83rnrn80: rn81: String szSql="select * from TBL_Bbs_Type order by Ord ";rn82: rn83: ConpoolRs Conpoolrs=myDBCtrl.DBAsk_ResultSet(szSql);rn84: rs=Conpoolrs.result;rn85: rn86: int i=0;rnrnrnStacktrace:rn org.apache.jasper.servlet.JspServletWrapper.handleJspException(JspServletWrapper.java:451)rn org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:373)rn org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)rn org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)rn javax.servlet.http.HttpServlet.service(HttpServlet.java:729)rnrnrnroot cause rnrnjava.lang.NullPointerExceptionrn com.dbctrl.DBCtrl.DBAsk_ResultSet(DBCtrl.java:335)rn org.apache.jsp.Jsp.dtree.Bbs_jsp._jspService(Bbs_jsp.java:128)rn org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:98)rn javax.servlet.http.HttpServlet.service(HttpServlet.java:729)rn org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:331)rn org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:329)rn org.apache.jasper.servlet.JspServlet.service(JspServlet.java:265)rn javax.servlet.http.HttpServlet.service(HttpServlet.java:729)rnrnrnnote The full stack trace of the root cause is available in the Apache Tomcat/5.5.27 logs.rnrnrn--------------------------------------------------------------------------------rnrnApache Tomcat/5.5.27
给了四个hpp文件，要求编辑出对应的四个对应的cpp文件，每一块都有相应注释，要求用pointer互指，使make.cpp可以成功compile。编译环境最好是linux（g＋＋）。输出结果应为true或false。跪求解答。题目要求如下：rnrnThis is the main exercise. As mentioned, the exercise practices copy construction. But it also has some aspects of input reading. You are asked to implement a package that will allow to implement a simple satisfiability solver (look up sat solving, links recommended by Alexey here and here). Essentially, the data structure implements a Boolean formula over Boolean variables in a certain format (CNF). The functionality that is added is particularly suitable to implement (very basic) solvers that can tell whether a given formula has an assignment that renders the formula true. The classes that are required are:rn1. Variable - a Boolean variable. A variable may be unset, which means that it's value is (currently) unknown, or set, in which case it is either true or false.rn2. Literal - this is either a variable or a negated variable.rn3. Clause - this is a disjunction of literals. In our package the clause is an array of literals. It has to be memory efficient (i.e., not allocate space for more literals than it actually has). In more efficient sat solvers, when a variable is set it notifies all the clauses in which it appears. For that, our variables are going to contain pointers to the clauses that contain them. Again, the Variable should not allocate more space than required for storing these pointers.rn4. Formula - this is the main class here. A formula is the conjunction of a set of clauses. It also contains all the variables that appears in these clauses in order to coordinate the solving process. Again, the containers in the Formula should not be larger than required.rnNotice that some of the options are quite advanced. For example, force in Clause, and resolve in Formula. As mentioned, the main point of the exercise is in the copy constructor of Formula. So you should invest most of your effort in that. If the different copy constructors work fine, then proceed to the more advanced options that go in the direction of sat solving.rnTechnically, I have created the header files of all these classes. You have to complete them with additional members and complete the implementations. You will have to submit eight files: Variable.*pp, Literal.*pp, Clause.*pp, and Formula.*pp. You can submit one additional file called Solver.cpp. This file can contain your own version of a sat solver that improves on the one that I included below. The Solver.cpp file has to contain a main and it will be compiled using the same Makefile that is supplied below. The header files include detailed descriptions of the functions that you are required to implement.rnrn下面是四个hpp文件和main.cpp文件：rnVariable.hpp:rn/*rn * Variable.hpprn *rn * Created on:rn * Author:rn */rnrn#ifndef VARIABLE_HPP_rn#define VARIABLE_HPP_rnrn#include rn#include rnrnclass Variable;rnrn#include "Clause.hpp"rnrnclass Variable rnpublic:rn // This is a basic Boolean variablern // It has an ID and is either set or unset (i.e., known or unknonw)rn // If it is set, it can be true or falsern // It also holds pointers to all the clauses that it appearsrn // in.rn Variable();rnrn // Initializes the identifierrn // The identifier of a real variable cannot be 0!rn Variable(unsigned int);rnrn // Copies the identifier and the status of the variablern // Does not copy the clauses (deep copy is orchestrated byrn // formula)rn Variable(const Variable &);rnrn // Clean you messrn ~Variable();rnrn // Return the value of the variablern // If the variable is not set return whatever you wantrn bool value() const;rnrn // Return whether the variable is set or notrn bool isSet() const;rnrn // Set the variable to the given valuern void set(bool);rnrn // Unset the variablern void unset();rnrn // Update the list of clauses in which the variable appearsrn void addedToClause(Clause* cl);rnrn // In how many clauses does the variable appearrn unsigned int numClauses() const;rnrn // Return a pointer to the i-th clause the variablern // is in.rn // Or NULL if there is no such clausern Clause* clause(unsigned int);rnrn // Return the idrn unsigned int id() const;rnrn // output ?/0/1 accoring to the set/unset value.rn std::string toString() const;rnprivate:rn // Add your own data members and member functions.rn;rnrnstd::ostream& operator<<(std::ostream&, const Variable&);rnrn#endif /* VARIABLE_HPP_ */rnrnFormula.hpp:rnrn/*rn * Formula.hpprn *rn * Created on:rn * Author:rn */rnrn#ifndef FORMULA_HPP_rn#define FORMULA_HPP_rnrn#include rn#include rnrnclass Formula;rnrn#include "Clause.hpp"rn#include "Variable.hpp"rnrn// A formula has a given set of variablesrn// and clauses that use these variables.rn// The total data structure that we are developing has a formularn// but it also contains a partial assignment to thern// variables appearing in the formula.rn// The assignment is partial as some variables could bern// unset.rn//rn// The partial assignment may be sufficient to deduce thatrn// the formula is satisfied but in most cases it is not sufficient.rn//rn// In case that the partial assignment is not sufficient therern// may be a fuller assignment that does satisfy the formula.rn// A SAT solver (see main.cpp) tries to extend thern// current assignment to a fuller assignment that satisfiesrn// the formula.rn//rn// Some of the functions, such as resolve(), tries to increasern// the assignment to a fuller assignment based on thern// constraints that the formula induces.rn//rnclass Formula rnpublic:rn Formula();rn // A deep copy.rn // This deep copy should orchestrate all the other classes sorn // that you get a deep copy of the entire formula.rn Formula(const Formula&);rnrn // Clean your messrn ~Formula();rnrn // If the variable exists returns truern // If the variable does not exist adds it andrn // return falsern bool addVar(unsigned int);rnrn // returns false if the variable does not existrn // If the variable does exist sets the pointerrn // reference to the pointer to this variablern bool findVar(unsigned int, Variable*&) const;rnrn // Returns the id of an unset variablern // If there is no unset variable it returns 0.rn unsigned int firstUnsetVar();rnrn // Adds a clause of size sizern // The values in the array are the identifiersrn // of the variables.rn // The identifier has negative value if it is negatedrn // it has positive value if it is not negatedrn void addClause(unsigned int size, int* array);rnrn // Set the variable id to the valuern // If the variable does not exist return falsern // Otherwise set the variable and return truern bool setVar(unsigned int id,bool value);rnrn // Unset the variable idrn // If the variable does not exist return falsern // Otherwise set the variable and return truern bool unsetVar(unsigned int id);rnrn // Return the value of variable idrn // If there is no such variable return falsern bool value(unsigned int id);rnrn // Is variable id set?rn // If there is no such variable return falsern bool isSet(unsigned int) const;rnrn // Is the formula satisfied?rn // The formula is satisfied if all the clauses in it arern // satisfiedrn bool sat() const;rnrn // Go over all clauses and check if some clausern // forces the value of a variable.rn // If it does then set the value to the forced value.rn // Continue until no more resolutions are possible.rn void resolve();rnrn // Output the formula in dimacs format (see below)rn // You can write whatever you want as initial commentsrn std::string toString() const;rnrn // Read a formula in dimacs formatrn // A formula can start with several lines of commentsrn // that are identified by the first character 'c'rn // You should ignore these lines.rn // Then, the formula has a line of the format:rn // p cnf numVars numClausesrn // numVars is the number of variables in the formularn // numClauses is the number of clauses that you need to readrn //rn // No comments appear after this line with prn // The only thing that appears from now on are numbersrn // according to the format explained below. If anythingrn // else appears the reading should fail and the streamrn // should be left with an error state.rn //rn // Then there is a list of clauses each in a separate linern // The structure of a clause is:rn // number number number .... number 0rn //rn // That is, you have a sequence of identifiers as positive or negativern // numbers.rn // The sequence ends with a 0.rn // You are allowed to ignore whatever appears after the 0 untilrn // the next line.rn // Line length is bounded by 1000.rn // This sequence represents a clause in which:rn // If the number is negative (e.g., -5) this means that therern // is literal with a negated variable of the identifier thatrn // matches the absolutern // value of the number (5 in the example).rn // If the number is positive (e.g., 5) this means that therern // is a literal with a varialbe of the identifier thatrn //rn // If there are faults during reading the formula you should leavern // the formula in parameter (reference) unchanged and leave the streamrn // with the appropriate error state.rn //rn // Notice the following two faults that should result in failurern // to read:rn // 1. The formula has a too small number of clausesrn // 2. The number of variables declared is differentrn // from the actual number of variables appearingrn // in the different clauses.rn friend std::istream& operator>>(std::istream&, Formula&);rnrnprivate:rn // Add your own data members and member functions.rn;rnrn// Write the toStringrnstd::ostream& operator<<(std::ostream&, const Formula&);rnrn#endif /* FORMULA_HPP_ */rn（未完）