java实现Spring在XML配置java类

java实现Spring在XML配置java类

1.创建自己的bean文件：beans.xml

<?xml version="1.0" encoding="UTF-8"?>
<busi-beans>
<beans>
<bean id="SysHelloImpl" type="com.cxm.test.SysHello">
<desc>test</desc>
<impl-class>com.cxm.test.SysHelloImpl</impl-class>
</bean>
</beans>
</busi-beans>

2,提供解析xml类：XmlUtils

/**
 * 
 */
package com.cxm.xmlutil;

import java.io.InputStream;
import java.util.Iterator;
import java.util.Map;

import org.jdom.Attribute;
import org.jdom.Document;
import org.jdom.Element;
import org.jdom.input.SAXBuilder;
import org.jdom.xpath.XPath;

import com.cxm.beaninfo.BeanInfo;



/**
 * @author admin
 * 
 */
public class XmlUtils
{

public static void parseXmlDef(InputStream in, Map<String,BeanInfo> beanDefMap,
StringBuffer sb) throws Exception
{
SAXBuilder reader = new SAXBuilder(false);
Document doc = null;
try
{
doc = reader.build(in);
Iterator beanIt = XPath.selectNodes(doc, "/busi-beans/beans/bean")
.iterator();
Element e;
BeanInfo beanDef;
while (beanIt.hasNext())
{
beanDef = new BeanInfo();
e = (Element) beanIt.next();
Attribute attrId = e.getAttribute("id");
Attribute attrType = e.getAttribute("type");
Attribute singleType = e.getAttribute("single");
boolean isSingle = true;
if(null != singleType&&"1".equals(singleType.getValue())){
isSingle= false;
}
beanDef.setSingle(isSingle);
beanDef.setBeanId(attrId.getValue());
beanDef.setType(attrType.getValue());
beanDef.setBeanDesc(getText(e, "desc"));
beanDef.setImplClassName(getText(e, "impl-class"));
//处理初始化参数
beanDefMap.put(attrId.getValue(), beanDef);
}
}
catch (Exception e)
{
e.printStackTrace();
}
}

/**
 * 根据指定的element, xPath获取XML文档内容
 * 
 * @param p_element
 * @param p_xPath
 * @return
 * @throws Exception
 */
public static String getText(Element p_element, String p_xPath)
throws Exception {
String text = null;
Element e=(Element)XPath.selectSingleNode(p_element,p_xPath);
if (e != null) {
text = e.getText();
} else {
}
return text;
}
}

3.定义bean IO

/**
 * 
 */
package com.cxm.beaninfo;

/**
 * @author admin
 *
 */
public class BeanInfo
{
private String beanId;

private String type;

private String beanDesc;

public String getBeanDesc()
{
return beanDesc;
}

public void setBeanDesc(String beanDesc)
{
this.beanDesc = beanDesc;
}

public String getType()
{
return type;
}

public void setType(String type)
{
this.type = type;
}

private String implClassName;

public String getBeanId()
{
return beanId;
}

public void setBeanId(String beanId)
{
this.beanId = beanId;
}

public String getImplClassName()
{
return implClassName;
}

public void setImplClassName(String implClassName)
{
this.implClassName = implClassName;
}

public boolean isSingle()
{
return isSingle;
}

public void setSingle(boolean isSingle)
{
this.isSingle = isSingle;
}

private boolean isSingle = true;

}

4.bean的创建类：BeanUtil

/**
 * 
 */
package com.cxm.bean;



/**
 * @author admin
 *
 */
public class BeanUtil
{
private static XmlBeanFactory factory = new XmlBeanFactory();
/**
 * 获取定义好的Bean对象
 * @param p_beanId
 * @return
 * @throws Exception 
 */
public static Object createBean(String p_beanId)
throws Exception {
return factory.createBean(p_beanId);
}
}

 

/**
 * 
 */
package com.cxm.bean;

import java.io.FileNotFoundException;
import java.io.InputStream;
import java.lang.reflect.Constructor;
import java.util.HashMap;
import java.util.Map;

import com.cxm.beaninfo.BeanInfo;
import com.cxm.exception.NoSuchBeanDefinitionException;
import com.cxm.xmlutil.XmlUtils;

/**
 * @author admin
 *
 */
public class XmlBeanFactory
{
private static String BEAN_XML = "/beans.xml";

private static Map<String,BeanInfo> beanDefMap = new HashMap<String,BeanInfo>();

private static Map<String,Object> instanceMap = new HashMap<String,Object>();

static {
InputStream in = XmlBeanFactory.class.getResourceAsStream(BEAN_XML);
if(in ==null){
try{
throw new FileNotFoundException();
}catch (FileNotFoundException e){
e.printStackTrace();
}
}
StringBuffer sb = new StringBuffer();
try
{
XmlUtils.parseXmlDef(in, beanDefMap, sb);
}
catch (Exception e)
{
throw new RuntimeException();
}
}

public Object createBean(String beanId) throws Exception{
if(beanId==null || beanId.trim()==""){
throw new Exception("BeanId can not NULL or '' ");
}
BeanInfo beanInfo = beanDefMap.get(beanId);
if(null ==beanInfo ){
throw new NoSuchBeanDefinitionException(" beanid is not define in xml");
}
Object instance;
if(beanInfo.isSingle()){
instance =instanceMap.get(beanId);
if(null != instance){
return instance;
}
}
String implClass = beanInfo.getImplClassName();
Constructor<?> constructor = Class.forName(implClass.trim()).getConstructor();
instance = constructor.newInstance();
if(beanInfo.isSingle()){
instanceMap.put(beanId, instance);
}
return instance;
}
}

5.测试：

/**
 * 
 */
package com.cxm.test;

/**
 * @author admin
 *
 */
public interface SysHello
{
void sysHello();
}

 

/**
 * 
 */
package com.cxm.test;

/**
 * @author admin
 *
 */
public class SysHelloImpl implements SysHello
{

@Override
public void sysHello()
{
System.out.println("hello world!");

}

}

 

/**
 * 
 */
package com.cxm.test;

import com.cxm.bean.BeanUtil;

/**
 * @author admin
 *
 */
public class Test
{

/**
 * @param args
 * @throws Exception 
 */
public static void main(String[] args) throws Exception
{
SysHello s = (SysHello)BeanUtil.createBean("SysHelloImpl");
s.sysHello();
}

}