JDBC不能运行build.xml类路径

Question

    I'm having trouble running from ant.  When I run straight from the class 
    file as follows it compiles and runs
    Jasons-MacBook-Pro:src js$ java Hw5
    Student ID:  1
    First Name:  Jason
    Last Name:  S
    Phone:  [phone]
    Email:  [e-mail]
    Personal Tagline:  Never say never
    The following line of code is used when it runs correctly as above
    Connection connection = DriverManager.getConnection("jdbc:derby:/Users/js/Desktop/JavaDevelopmentAnt/HW5_JDBC/lib/Hw5Db");
    my code
    import java.sql.*;
    import java.util.Enumeration;
    public class Hw5{
       public static void main (String [] args){
          try{
             Connection connection = DriverManager.getConnection("jdbc:derby:/Users/js/Desktop/JavaDevelopmentAnt/HW5_JDBC/lib/Hw5Db");
             //Connection connection = DriverManager.getConnection("jdbc:derby:Hw5Db");//ant file code
             Statement statement = connection.createStatement();
             ResultSet resultSet = statement.executeQuery("SELECT * FROM STUDENT");
             while(resultSet.next()){
                int studentID = resultSet.getInt("STUDENT_ID");
                String firstName = resultSet.getString("FIRSTNAME");
                String lastName = resultSet.getString("LASTNAME");
                String phone = resultSet.getString("PHONE");
                String email = resultSet.getString("EMAIL");
                String mantra = resultSet.getString("PERSONAL_TAGLINE");
                System.out.println("Student ID:  " + studentID + "n" + 
                                "First Name:  " + firstName + "n" + 
                                "Last Name:  " + lastName + "n" +
                                "Phone:  " + phone + "n" +
                                "Email:  " + email + "n" +
                                "Personal Tagline:  " + mantra + "n");
             }
             resultSet.close();
             statement.close();
             connection.close();         
          }
          catch(SQLException sqle){
             System.err.println("SQL Exception: " + sqle);
          }
       }
    }

    but when I try from my build.xml  i change the following line of code to
    Connection connection = DriverManager.getConnection("jdbc:derby:Hw5Db");
    because i think database jar file (Hw5Db) is in the classpath of my build.xml
    my build.xml

<?xml version="1.0"?>
   <project name="Hw5" default="compile" basedir=".">
   <property environment="env"/>
   <property name="src" value="${basedir}/src"/>
   <property name="bin" value="${basedir}/bin"/>
   <property name="lib" value="${basedir}/lib"/>
   <property name="doc" value="${basedir}/doc"/>
   <property name="build" value="${basedir}/build"/>
   <target name="prepare" description="Setting up temporary directory to support build">
      <mkdir dir="${build}"/>
      <mkdir dir="${bin}"/>
   </target>
   <target name="compile" depends="prepare" description="compile java sources">
      <javac srcdir="${src}" destdir="${build}" includes="**/*.java" listfiles="yes" includeantruntime="false">
      </javac>
   </target>
   <target name="deploy" depends="compile">
      <jar destfile="${bin}/Hw5.jar" basedir="${build}"/>
      <jar destfile="${bin}/Hw5Db.jar" basedir="${lib}"/>
    </target>
    <target name="run" depends="deploy" description="run the project">
       <java fork="true" classname="Hw5">
          <classpath path="${bin}/Hw5.jar"/>
          <classpath path="${bin}/Hw5Db.jar"/>
       </java>
    </target>
    <target name="clean">
       <delete dir="${build}"/>
       <delete dir="${bin}"/>
    </target>
</project>
Jasons-MacBook-Pro:HW5_JDBC jsteindorf$ ant run
    Buildfile: /Users/js/Desktop/JavaDevelopmentAnt/HW5_JDBC/build.xml
    prepare:
        [mkdir] Created dir: /Users/js/Desktop/JavaDevelopmentAnt/HW5_JDBC/build
        [mkdir] Created dir: /Users/js/Desktop/JavaDevelopmentAnt/HW5_JDBC/bin
    compile:
        [javac] Compiling 1 source file to /Users/js/Desktop/JavaDevelopmentAnt/HW5_JDBC/build
        [javac] /Users/js/Desktop/JavaDevelopmentAnt/HW5_JDBC/src/Hw5.java
    deploy:
          [jar] Building jar: /Users/jsteindorf/Desktop/JavaDevelopmentAnt/HW5_JDBC/bin/Hw5.jar
          [jar] Building jar: /Users/jsteindorf/Desktop/JavaDevelopmentAnt/HW5_JDBC/bin/Hw5Db.jar
    run:
         [java] SQL Exception: java.sql.SQLException: No suitable driver found for jdbc:derby:Hw5Db
    BUILD SUCCESSFUL
    Total time: 2 seconds    
    I'm trying, I just can't get it to work

Answer 1

不确定，但也许你需要在使用它之前注册驱动程序。

Class.forName("class_of_driver").getInstance();  

之后:

Connection connection = DriverManager.getConnection("jdbc:derby:./Hw5Db");

Answer 2

在java任务上复制的classpath对我来说看起来有点奇怪。试试下面的命令:

<java fork="true" classname="Hw5">
     <classpath path="${bin}/Hw5.jar:${bin}/Hw5Db.jar"/>
</java>

Answer 3

我修复了这个问题，build.xml没有找到数据库驱动程序

类路径路径= " $ {env.DERBY_HOME}/lib/derby.jar

类路径路径= " $ {env.DERBY_HOME}/lib/derbytools.jar

和数据库的连接路径应该是

jdbc: derby:。/lib/Hw5Db