WebLogic的研究之－开发、部署EJB(1)
这里不会讨论EJB的概念，只讨论如何编写一个简单EJB，部署EJB，Weblogic与JBuilder的整合，本文先把介绍仅用文本编辑器编写一个最简单的EJB所需要的一切，以让大家一览EJB的概貌，然后才介绍如何把Weblogic与JBuilder整合起来，使用JBuilder开发Weblogic的EJB，我相信这样会得到很好的学习效果，因为这是我学习的路径，当然我会把我遇到的问题告诉大家，以免大家走弯路。
下面是一个最简单的EJB所需要的代码及XML说明，手工制作EJB的JAR包比较麻烦，在WIN2000下，我仿照例子制作了一个 build.cmd 批处理文件
weblogic-ejb-jar.xml
< ?xml version="1.0"? >
< !DOCTYPE weblogic-ejb-jar PUBLIC -//BEA Systems, Inc.//DTD WebLogic 5.1.0 EJB//EN http://www.bea.com/servers/wls510/dtd/weblogic-ejb-jar.dtd >
< weblogic-ejb-jar >
< weblogic-enterprise-bean >
< ejb-name >HelloWorldBean< /ejb-name >
< caching-descriptor >
< max-beans-in-free-pool >100< /max-beans-in-free-pool >
< /caching-descriptor >
< jndi-name >hello.HelloWorld< /jndi-name >
< /weblogic-enterprise-bean >
< /weblogic-ejb-jar
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ejb-jar.xml
< ?xml version="1.0" encoding="GBK"? >
< !DOCTYPE ejb-jar PUBLIC -//Sun Microsystems, Inc.//DTD Enterprise JavaBeans 1.1//EN http://java.sun.com/j2ee/dtds/ejb-jar_1_1.dtd >
< ejb-jar >
< enterprise-beans >
< session >
< ejb-name >HelloWorldBean< /ejb-name >
< home >hello.HelloWorldHome< /home >
< remote >hello.HelloWorld< /remote >
< ejb-class >hello.HelloWorldBean< /ejb-class >
< session-type >Stateless< /session-type >
< transaction-type >Container< /transaction-type >
< /session >
< /enterprise-beans >
< assembly-descriptor >
< container-transaction >
< method >
< ejb-name >HelloWorldBean< /ejb-name >
< method-name >*< /method-name >
< /method >
< trans-attribute >Required< /trans-attribute >
< /container-transaction >
< /assembly-descriptor >
< /ejb-jar >
--------------------------------------------------------------------------------
package hello;
import java.rmi.*;
import javax.ejb.*;
public class HelloWorldBean implements SessionBean {
private SessionContext sessionContext;
public void ejbCreate() {
}
public void ejbRemove() {
}
public void ejbActivate() {
}
public void ejbPassivate() {
}
public void setSessionContext(SessionContext context) {
sessionContext = context;
}
public String getHelloWorld(){
return "Hello World!";
}
}
--------------------------------------------------------------------------------
HelloWorld.java
package hello;
import java.rmi.*;
import javax.ejb.*;
public inte易做图ce HelloWorld extends EJBObject {
public java.lang.String getHelloWorld() throws RemoteException;
}
--------------------------------------------------------------------------------
HelloWorldHome.java
package hello;
import java.rmi.*;
import javax.ejb.*;
public inte易做图ce HelloWorldHome extends EJBHome {
public HelloWorld create() throws RemoteException, CreateException;
}
--------------------------------------------------------------------------------
HelloWorldBean.java
package hello;
import java.rmi.*;
import javax.ejb.*;
public class HelloWorldBean implements SessionBean {
private SessionContext sessionContext;
public void ejbCreate() {
}
public void ejbRemove() {
}
public void ejbActivate() {
}
public void ejbPassivate() {
}
public void setSessionContext(SessionContext context) {
sessionContext = context;
}
public String getHelloWorld(){
return "Hello World!";
}
}
--------------------------------------------------------------------------------
HelloWorldBeanClient1.java
package hello;
import javax.naming.*;
import javax.rmi.PortableRemoteObject;
public class HelloWorldBeanClient1 {
private static final String ERROR_NULL_REMOTE = "Remote inte易做图ce reference is null. It must be created by calling one of the Home inte易做图ce methods first.";
private static final int MAX_OUTPUT_LINE_LENGTH = 50;
private boolean logging = true;
private HelloWorldHome helloWorldHome = null;
private HelloWorld helloWorld = null;
/**Construct the EJB test client*/
public HelloWorldBeanClient1() {
long startTime = 0;
if (logging) {
log("Initializing bean access.");
startTime = System.currentTimeMillis();
}
try {
//get naming context
Context ctx = new InitialContext();
//look up jndi name
Object ref = ctx.lookup("HelloWorld");
//cast to Home inte易做图ce
helloWorldHome = (HelloWorldHome) PortableRemoteObject.narrow(ref, HelloWorldHome.class);
if (logging) {
long endTime = System.currentTimeMillis();
log("Succeeded initializing bean access.");
log("Execution time: " + (endTime - startTime) + " ms.");
}
HelloWorld hello=helloWorldHome.create();
String str=hello.getHelloWorld();
System.out.println(str);
}
catch(Exception e) {
if (logging) {
log("Failed initializing bean access.");
}
e.printStackTrace();
}
}
//----------------------------------------------------------------------------
// Methods that use Home inte易做图ce methods to generate a Remote inte易做图ce reference
//----------------------------------------------------------------------------
public HelloWorld create() {
long startTime = 0;
if (logging) {
log("Calling create()");
startTime = System.currentTimeMillis();
}
try {
helloWorld = helloWorldHome.create();
if (logging) {
long endTime = System.currentTimeMillis();
log("Succeeded: create()");
log("Execution time: " + (endTime - startTime) + " ms.");
}
}
catch(Exception e) {
if (logging) {
log("Failed: create()");
}
e.printStackTrace();
}
if (logging) {
log("Return value from create(): " + helloWorld + ".");
}
return helloWorld;
}
//----------------------------------------------------------------------------
// Methods that use Remote inte易做图ce methods to access data through the bean
//----------------------------------------------------------------------------
public String getHelloWorld() {
String returnValue = "";
if (helloWorld == null) {
System.out.println("Error in getHelloWorld(): " + ERROR_NULL_REMOTE);
return returnValue;
}
long startTime = 0;
if (logging) {
log("Calling getHelloWorld()");
startTime = System.currentTimeMillis();
}
try {
returnValue = helloWorld.getHelloWorld();
if (logging) {
long endTime = System.currentTimeMillis();
log("Succeeded: getHelloWorld()");
log("Execution time: " + (en
补充：软件开发 , Java ,
