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