关于jdbc

Question

import java.sql.Connection;
import java.util.Properties;
import javax.sql.DataSource;import org.apache.commons.dbcp.BasicDataSourceFactory;public final class DBUtil {
private static DataSource ds;
private static ThreadLocal<Connection> connLocal=new ThreadLocal<Connection>();
static{
try {

Properties props = new Properties();
props.load(DBUtil.class.getClassLoader().getResourceAsStream(
"dbcp.properties"));
ds = BasicDataSourceFactory.createDataSource(props);
System.out.println("here------------------------------------------");
} catch (Exception e) {
e.printStackTrace();
}
}
public static Connection getConnection(){
Connection conn = connLocal.get();
try {
if(conn == null){
 conn =  ds.getConnection();
connLocal.set(conn);
}
return conn;
} catch (Exception e) {
e.printStackTrace();
return null;
}
}

public static void close(){
Connection conn = connLocal.get();
connLocal.set(null);
if(conn != null){
try {
conn.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}
}各位大虾帮帮忙，每次初始化这个类的时候上面的输出语句不输出。
所有导入的包都是正确的。

Answer 1

dbcp.properties文件内容需要贴出来连接什么数据库，数据库驱动有没加

Answer 2

是不是用了 插件啊 我这里显示 ds = BasicDataSourceFactory.createDataSource(props); 编译报错找不到createDataSource(props);方法

Answer 3

driverClassName=com.mysql.jdbc.Driver
url=jdbc\:mysql\://localhost\:3306/p2
username=root
password=tarenainitialSize=2maxActive=10maxIdle=2minIdle=1maxWait=30000

Answer 4

 public static void main(String[] args) throws ClassNotFoundException {
Class.forName("DBUtil");
}加上此句测试正常有打印语句，估计你是无加载这个类吧，我觉得你写的代码没有问题

Answer 5

额。很郁闷，单独运行没有任何问题，但是放在myeclipse和工程一起运行就有问题，控制台不报错，而且不输出那条打印语句，放在前面就会输出。
浏览器的错误报告如下：HTTP Status 500 -type Exception reportmessagedescription The server encountered an internal error () that prevented it from fulfilling this request.exceptionjava.lang.reflect.InvocationTargetException
sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
java.lang.reflect.Method.invoke(Method.java:597)
com.opensymphony.xwork2.DefaultActionInvocation.invokeAction(DefaultActionInvocation.java:440)
com.opensymphony.xwork2.DefaultActionInvocation.invokeActionOnly(DefaultActionInvocation.java:279)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:242)
com.opensymphony.xwork2.interceptor.DefaultWorkflowInterceptor.doIntercept(DefaultWorkflowInterceptor.java:163)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
com.opensymphony.xwork2.validator.ValidationInterceptor.doIntercept(ValidationInterceptor.java:249)
org.apache.struts2.interceptor.validation.AnnotationValidationInterceptor.doIntercept(AnnotationValidationInterceptor.java:68)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
com.opensymphony.xwork2.interceptor.ConversionErrorInterceptor.intercept(ConversionErrorInterceptor.java:122)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
com.opensymphony.xwork2.interceptor.ParametersInterceptor.doIntercept(ParametersInterceptor.java:195)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
com.opensymphony.xwork2.interceptor.StaticParametersInterceptor.intercept(StaticParametersInterceptor.java:148)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
org.apache.struts2.interceptor.CheckboxInterceptor.intercept(CheckboxInterceptor.java:93)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
org.apache.struts2.interceptor.FileUploadInterceptor.intercept(FileUploadInterceptor.java:235)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
com.opensymphony.xwork2.interceptor.ModelDrivenInterceptor.intercept(ModelDrivenInterceptor.java:89)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
com.opensymphony.xwork2.interceptor.ScopedModelDrivenInterceptor.intercept(ScopedModelDrivenInterceptor.java:128)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
org.apache.struts2.interceptor.ProfilingActivationInterceptor.intercept(ProfilingActivationInterceptor.java:104)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
org.apache.struts2.interceptor.debugging.DebuggingInterceptor.intercept(DebuggingInterceptor.java:267)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
com.opensymphony.xwork2.interceptor.ChainingInterceptor.intercept(ChainingInterceptor.java:126)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
com.opensymphony.xwork2.interceptor.PrepareInterceptor.doIntercept(PrepareInterceptor.java:138)
com.opensymphony.xwork2.interceptor.MethodFilterInterceptor.intercept(MethodFilterInterceptor.java:87)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
com.opensymphony.xwork2.interceptor.I18nInterceptor.intercept(I18nInterceptor.java:148)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
org.apache.struts2.interceptor.ServletConfigInterceptor.intercept(ServletConfigInterceptor.java:164)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
com.opensymphony.xwork2.interceptor.AliasInterceptor.intercept(AliasInterceptor.java:128)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
com.opensymphony.xwork2.interceptor.ExceptionMappingInterceptor.intercept(ExceptionMappingInterceptor.java:176)
com.opensymphony.xwork2.DefaultActionInvocation.invoke(DefaultActionInvocation.java:236)
org.apache.struts2.impl.StrutsActionProxy.execute(StrutsActionProxy.java:52)
org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:468)
org.apache.struts2.dispatcher.ng.ExecuteOperations.executeAction(ExecuteOperations.java:77)
org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter.doFilter(StrutsPrepareAndExecuteFilter.java:76)note The full stack trace of the root cause is available in the Apache Tomcat/5.5.12 logs.

Answer 6

我想应该是你struts2项目当中出了问题，问题可能不是在这个DBUtil上面，
那行语句不输出也是因为程序有异常的缘故