javac 编译找不到符号

javac 编译找不到符号 问题描述: >javac course.java course.java:31:找不到符号 符号:类sqlBean 位置:类bean.course sqlBean db=new sqlBean <>; …… course.java和sqlBean.java及其他一些文件同放于bean文件夹下 course.java: package bean; import java.sql.*; public class course { private String id; private String name; private String dep; private String prepare; private int mark; public void setPrepare(String s){prepare=s;} public String getPrepare(){return prepare;} public void setMark(int s){mark=s;} public int getMark(){return mark;} public void setDep(String s){dep=s;} public String getDep(){return dep;} public String getId() { return id; } public void setId(String id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public ResultSet getPrepares(){ //得到所能选择的预修课 String sql="select name,id from course "; sqlBean db = new sqlBean(); ResultSet rs = db.executeQuery(sql); return rs; } public String getPrepareDep(){ //察看预修课所在系 String s="no"; String sql="select dep from course where id='" prepare "' "; sqlBean db = new sqlBean(); try{ ResultSet rs = db.executeQuery(sql); if(rs.next()){ s=rs.getString("dep"); } }catch(Exception e){ e.getMessage();} return s;} public ResultSet getCourse(){ //察看所有课程 String sql="select * from course "; sqlBean db= new sqlBean(); ResultSet rs = db.executeQuery(sql); return rs; } public int deleteCourse(String id){ int num=0; String sql="delete from Course where id ='" id "' "; sqlBean db= new sqlBean(); num=db.executeDelete(sql); return num; } public String getPrepareDep(String id){ String dep=""; String sql="select dep from course where id='" id "'"; sqlBean db= new sqlBean(); try{ ResultSet rs = db.executeQuery(sql); if(rs.next()) dep=rs.getString("dep"); }catch(SQLException e){System.out.print(e.toString());} return dep; } public void updateCourse(String id){ String sql="update course " " set name='" name "',prepare='" prepare "'," "dep='" dep "',mark='" mark "' " " where id='" id "' "; sqlBean db= new sqlBean(); db.executeInsert(sql); } public void addCourse(){ String sql="insert into course(id,name,mark,prepare,dep) " "VALUES ('" id "','" name "','" mark "','" prepare "','" dep "') "; sqlBean db = new sqlBean(); db.executeInsert(sql); } public boolean hasLogin( String id){ boolean f=true; String sql="select id from course where id='" id "' "; sqlBean db = new sqlBean(); try{ ResultSet rs =db.executeQuery(sql); if(rs.next()) {f=false;} }catch(Exception e){ e.getMessage();} return f; } } sqlBean.java: package bean; import java.io.*; import java.sql.*; public class sqlBean{/// public Connection conn=null; public ResultSet rs=null; private String DatabaseDriver="sun.jdbc.odbc.JdbcOdbcDriver"; //DataSource 数据源名称DSN private String DatabaseConnStr="jdbc:odbc:ClassDB2,'sa',"; //定义方法 /*setXxx用于设置属性值;getXxx用于得到属性值*/ public void setDatabaseDriver(String Driver){ this.DatabaseDriver=Driver; } public String getDatabaseDriver(){ return (this.DatabaseDriver); } public void setDatabaseConnStr(String ConnStr){ this.DatabaseConnStr=ConnStr; } public String getDatabaseConnStr(){ return (this.DatabaseConnStr); } public sqlBean(){/////构造函数 try{ Class.forName(DatabaseDriver); } catch(java.lang.ClassNotFoundException e){ System.err.println("加载驱动器有错误:" e.getMessage( )); System.out.print("执行插入有错误:" e.getMessage());//输出到客户端 } } public int executeInsert(String sql){ int num=0; try{ conn = DriverManager.getConnection("jdbc:odbc:ClassDB","sa",""); Statement stmt=conn.createStatement( ); num=stmt.executeUpdate(sql); } catch(SQLException ex){ System.err.println("执行插入有错误:" ex.getMessage() ); System.out.print("执行插入有错误:" ex.getMessage());//输出到客户端 } CloseDataBase(); return num; } // display data public ResultSet executeQuery(String sql){ rs=null; try{ conn = DriverManager.getConnection("jdbc:odbc:ClassDB","sa",""); Statement stmt=conn.createStatement( ); rs=stmt.executeQuery(sql); } catch(SQLException ex){ System.err.println("执行查询有错误:" ex.getMessage() ); System.out.print("执行查询有错误:" ex.getMessage()); //输出到客户端 } return rs; } // delete data public int executeDelete(String sql){ int num=0; try{ conn = DriverManager.getConnection("jdbc:odbc:ClassDB","sa",""); Statement stmt=conn.createStatement( ); num=stmt.executeUpdate(sql); } catch(SQLException ex){ System.err.println("执行删除有错误:" ex.getMessage() ); System.out.print("执行删除有错误:" ex.getMessage()); //输出到客户端 } CloseDataBase(); return num; } ////////////////// public void CloseDataBase(){ try{ conn.close(); } catch(Exception end){ System.err.println("执行关闭Connection对象有错误:" end.getMessage( ) ); System.out.print("执行执行关闭Connection对象有错误:有错误:" end.getMessage()); //输出到客户端 } } } 到bean文件夹所在目录去编译: javac bean/course.java 或者 javac bean/*.java 因为package 写着是 bean 那这两个文件就应该在bean文件夹下面。。 运行也一样在bean所在文件夹: java bean.course