好难嗄！！！求高手···（jsp+servlet+javabeen）
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1360)
at org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1206)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
at java.lang.Class.forName0(Native Method)
at java.lang.Class.forName(Class.java:169)
at sms.db.DBAccess.getConnection(DBAccess.java:91)
at sms.bean.StudentBean.queryStuInfo(StudentBean.java:126)
at org.apache.jsp.login_jsp._jspService(login_jsp.java:56)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:324)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Thread.java:619)
2012-5-30 21:12:46 org.apache.catalina.core.StandardWrapperValve invoke
严重: Servlet.service() for servlet jsp threw exception
java.lang.NullPointerException
at sms.db.DBAccess.query(DBAccess.java:137)
at sms.db.DBAccess.getSysDate(DBAccess.java:246)
at sms.bean.StudentBean.queryStuInfo(StudentBean.java:128)
at org.apache.jsp.login_jsp._jspService(login_jsp.java:56)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:94)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:324)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:292)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:236)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:803)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:844)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Thread.java:619)
//附上数据库连接的类
package sms.db;
import java.sql.SQLException;
import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.Statement;
import javax.sql.DataSource;
import java.sql.DriverManager;
import javax.naming.*;
public class DBAccess {
/**
* 数据库连接
*/
private Connection conn = null;
/**
* jdbc的Statement类型变量
*/
private Statement stmt = null;
/**
*jdbc的结果集类型变量
*/
private ResultSet rs = null;
/**
* 用于实现数据库连接的数据源
*/
// private DataSource dataSource = null;
/**
* 是否用于调试
*/
private boolean debug = true;
/**
* 直接使用JDBC连接数据据库时的连接字符串
*/
private String dbUrlStr = "jdbc:mysql://localhost:3306/smsdb?user=root&password=111111&useUnicode=true&characterEncoding=gbk";
/**
* 直接使用JDBC连接数据据库时的驱动程序名
*/
private String driverName = "com.mysql.jdbc.Driver";
/**
* 构造函数
*/
public DBAccess() {}
public DBAccess(boolean debug) {
this.debug = debug;
}
/**
* 返回一个数据库连接
* @return Connection
*/
public void setDbUrlParameter(String driverName, String urlStr) {
if (driverName == null) {
driverName = "com.mysql.jdbc.Driver";
} else {
this.driverName = driverName;
}
if (urlStr == null) {
this.dbUrlStr = "jdbc:mysql://localhost:3306/smsdb?user=root&password=111111&useUnicode=true&characterEncoding=gbk";
} else {
this.dbUrlStr = urlStr;
}
}
/**
* 返回一个数据库连接
* @return Connection
*/
public Connection getConn() {
if (conn == null) {
getConnection();
}
return conn;
}
/**
* 取得一个数据库连接
*/
public void getConnection() {
try {
System.out.println("ccc");
if (this.debug) {
Class.forName(this.driverName);
this.conn = DriverManager.getConnection(dbUrlStr);
this.stmt = this.conn.createStatement();
System.out.println("数据库连接建立！");
} else {
javax.naming.Context ctx = new javax.naming.InitialContext();
javax.sql.DataSource ds = (javax.sql.DataSource) ctx.lookup(
"java:comp/env/jdbc/smsdb");
this.conn = ds.getConnection();
this.stmt = this.conn.createStatement();
System.out.println("数据库连接建立(连接池)！");
}
} catch (NamingException ex1) {
System.out.println("请检查数据库连接池配置是否正确！");
ex1.printStackTrace();
} catch (SQLException ex2) {
System.out.println("请检查数据库是否启动！");
ex2.printStackTrace();
} catch (ClassNotFoundException ex3) {
System.out.println("请检查数据库驱动程序是否正确！");
ex3.printStackTrace();
}
}
/**
* 通过连接池建立连接
* @param dataSource DataSource
*/
public void getConnection(DataSource dataSource) {
try {
conn = dataSource.getConnection();
stmt = conn.createStatement();
System.out.println("bbb");
} catch (SQLException ex) {
System.out.println("请检查数据库是否启动！");
ex.printStackTrace();
}
}
/**
* 按sql查询数据，返回数据结果集
*/
public ResultSet query(String strSql) {
//System.out.println("sql:" + strSql);
ResultSet rs = null;
try {
rs = stmt.executeQuery(strSql);
return rs;
} catch (SQLException ex) {
ex.printStackTrace();
return rs;
}
}
/**
* 数据库中数据更新的方法
* @param strSql String
* @return int
*/
public int executeSql(String strSql) {
System.out.println("sql:" + strSql);
int result = 0;
try {
stmt = conn.createStatement();
result = stmt.executeUpdate(strSql);
} catch (SQLException ex) {
System.out.println("产生异常,：at DBAccess.executeSql()");
ex.printStackTrace();
}
return result;
}
/**
* 关闭数据库连接
*/
public void closeConnection() {
try {
if (rs != null) {
rs.close();
rs = null;
}
if (stmt != null) {
stmt.close();
stmt = null;
}
if (conn != null) {
conn.close();
conn = null;
}
System.out.println("数据库连接关闭！");
} catch (SQLException ex) {
System.out.println("产生异常：at DBAccess.closeConnection()");
ex.printStackTrace();
}
}
/**
* 得到系统时间的方法
* @return String
*/
public static String getSysDate() {
DBAccess dba = new DBAccess();
String sql = "select sysdate() sysdate;";
try {
dba.getConnection();
ResultSet rs = dba.query(sql);
String currentDate = null;
if (rs.next()) {
currentDate = rs.getString("sysdate");
}
return currentDate;
} catch (SQLException ex) {
System.out.println("产生异常：at DBAccess.getSysDate()");
ex.printStackTrace();
return null;
} finally {
dba.closeConnection();
}
}
public static void main(String[] args) {
DBAccess db= new DBAccess();
System.out.println("aaa");
}
}
[解决办法]
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
根本就是漏了把MySQL的驱动jar包加入Classpath或者引入工程嘛。。。
------解决方案--------------------
java.lang.ClassNotFoundException: com.mysql.jdbc.Driver
换个驱动
[解决办法]
mysql-connector-java-5.0.8.zip ？！
怎么会是zip？应该是 jar ！
