spring 第9天 Resurce 资源访问
[size=medium][b]Spring Resource接口[/b][/size]
spring提供的Resource接口,改进了Java的访问策略,提供了更强的资源访问能力
主要方法如下
//Resource的实现类
[b]UrlResource[/b]
[b]ClassPathResource[/b]
[b]FileSystemResource[/b]
[b]ServletContextResource[/b]
[b]ByteStreamResource[/b]
[b]ResourceLoader可以获取一个Resource实例[/b]
ApplicationContext接口实现了 ResourceLoader接口
[b]ResourceLoaderAware:该接口可以获取到一个ResourceLoader[/b]
[b]使用Resource作为属性[/b]
[b] 在ApplicatoinContext中使用资源[/b]
//第一种方式
//第二中方式 采用前缀访问策略
//第三种方式 使用classpath*: 前缀
//第四种方式 使用file:前缀
spring提供的Resource接口,改进了Java的访问策略,提供了更强的资源访问能力
主要方法如下
getInputStream():定位并打开资源,返回资源对应的流,每次调用都返回新的输入流,调用者必须关闭
existx() 返回Resource所指向的资源是否存在
isOpen() 返回资源文件是否存在
getDescription() 返回资源的描述信息,用户资源处理出错是输入该信息,通常是全限定文件名和实际的URL
getFile() 返回资源对应的file对象
getURL() 返回资源对应的URL对象
//Resource的实现类
[b]UrlResource[/b]
package annotation.resources;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
import org.springframework.core.io.UrlResource;
/**
* Spring 的Resource 采用 策略模式 即使不用spring 也可以当作工具类来使用
* @author Bin
*/
public class UrlResourceTest {
public static void main(String[] args) throws DocumentException, IOException{
UrlResource ur=new UrlResource("file:book.xml");
System.out.println(ur.getFilename());
System.out.println(ur.getDescription());
SAXReader read=new SAXReader();
Document doc=read.read(ur.getFile());
Element root=doc.getRootElement();
List list=root.elements();
for (Iterator it=list.iterator(); it.hasNext();) {
Element book=it.next();
List ll=book.elements();
for (Iterator it2=ll.iterator(); it2.hasNext();) {
Element book1=it2.next();
System.out.println(book1.getName());
System.out.println(book1.getText());
}
}
}
}
[b]ClassPathResource[/b]
package annotation.resources;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
import org.springframework.core.io.ClassPathResource;
public class ClassPathResourceTest {
public static void main(String[] args) throws DocumentException, IOException {
ClassPathResource cr=new ClassPathResource("applicationContent_anno.xml");
System.out.println(cr.getFilename());
System.out.println(cr.getDescription());
SAXReader read=new SAXReader();
Document doc=read.read(cr.getFile());
Element root=doc.getRootElement();
List list=root.elements();
for (Iterator it=list.iterator(); it.hasNext();) {
Element book=it.next();
List ll=book.elements();
System.out.println(book.getName());
for (Iterator it2=ll.iterator(); it2.hasNext();) {
Element book1=it2.next();
System.out.println(book1.getName());
System.out.println(book1.getText());
}
}
}
}
[b]FileSystemResource[/b]
package annotation.resources;
import java.util.Iterator;
import java.util.List;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
import org.springframework.core.io.FileSystemResource;
public class FileSystemResourceTest {
public static void main(String[] args) throws DocumentException {
FileSystemResource fr=new FileSystemResource("src\\main\\resources\\applicationContent_anno.xml");
System.out.println(fr.getFilename());
System.out.println(fr.getDescription());
SAXReader read=new SAXReader();
Document doc=read.read(fr.getFile());
Element root=doc.getRootElement();
List list=root.elements();
for (Iterator it=list.iterator(); it.hasNext();) {
Element book=it.next();
List ll=book.elements();
System.out.println(book.getName());
for (Iterator it2=ll.iterator(); it2.hasNext();) {
Element book1=it2.next();
System.out.println(book1.getName());
System.out.println(book1.getText());
}
}
}
}
[b]ServletContextResource[/b]
<%
ServletContextResource src=new ServletContextResource(applicationContxt,"WEB-INf/book.xml");
System.out.println(src.getFilename());
System.out.println(src.getDescription());
SAXReader read=new SAXReader();
Document doc=read.read(src.getFile());
..
%>
[b]ByteStreamResource[/b]
package annotation.resources;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
import org.springframework.core.io.ByteArrayResource;
public class ByteArrayResourcesTest {
public static void main(String[] args) throws DocumentException, IOException {
// TODO Auto-generated method stub
String file=""
+"dom4j "
+"dom4j "
+"1.6.1 "
+" ";
byte[] filebytes=file.getBytes();
ByteArrayResource bar=new ByteArrayResource(filebytes);
System.out.println(bar.getDescription());
SAXReader read=new SAXReader();
Document doc=read.read(bar.getInputStream());
Element root=doc.getRootElement();
List list=root.elements();
for (Iterator it=list.iterator(); it.hasNext();) {
Element book=it.next();
List ll=book.elements();
System.out.println(book.getName());
for (Iterator it2=ll.iterator(); it2.hasNext();) {
Element book1=it2.next();
System.out.println(book1.getName());
System.out.println(book1.getText());
}
}
}
}
[b]ResourceLoader可以获取一个Resource实例[/b]
ApplicationContext接口实现了 ResourceLoader接口
package annotation.resources;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.context.support.FileSystemXmlApplicationContext;
import org.springframework.core.io.Resource;
//查看 spring 采用那个类来加载 资源文件
public class ResourceAwareTest {
public static void main(String[] args) throws DocumentException, IOException {
// TODO Auto-generated method stub
ApplicationContext act=new ClassPathXmlApplicationContext("applicationContent_anno.xml");
//ApplicationContext act=new FileSystemXmlApplicationContext("applicationContent_anno.xml");
Resource res=act.getResource("applicationContent_anno.xml");
//通过指定前缀 ,来强制使用特定的类来加载资源文件
res=act.getResource("classpath:bean.xml");
res=act.getResource("file:bean.xml");
res=act.getResource("http://location:8080/bean.xml");
System.out.println(res.getFilename());
System.out.println(res.getDescription());
SAXReader read=new SAXReader();
Document doc=read.read(res.getFile());
Element root=doc.getRootElement();
List list=root.elements();
for (Iterator it=list.iterator(); it.hasNext();) {
Element book=it.next();
List ll=book.elements();
System.out.println(book.getName());
for (Iterator it2=ll.iterator(); it2.hasNext();) {
Element book1=it2.next();
System.out.println(book1.getName());
System.out.println(book1.getText());
}
}
}
}
[b]ResourceLoaderAware:该接口可以获取到一个ResourceLoader[/b]
package annotation.resources;
import org.springframework.context.ResourceLoaderAware;
import org.springframework.core.io.ResourceLoader;
import org.springframework.stereotype.Component;
@Component
public class TestBean implements ResourceLoaderAware {
ResourceLoader rd;
@Override
public void setResourceLoader(ResourceLoader resourceLoader) {
// TODO Auto-generated method stub
this.rd=resourceLoader;
}
public ResourceLoader getRd() {
return rd;
}
public void setRd(ResourceLoader rd) {
this.rd = rd;
}
}
//测试 ResourceLoader
@Test
public void test2() { //
TestBean test=act.getBean("testBean",TestBean.class);
ResourceLoader rl=test.getRd();
//可以看到 true 表明: spring将自己注入到 TestBean 中了
System.out.println(rl==act);
Resource res=rl.getResource("applicationContent_anno.xml");
}
[b]使用Resource作为属性[/b]
package annotation.resources;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.core.io.Resource;
import org.springframework.stereotype.Component;
@Component
public class TestBean1 {
@Value("classpath:applicationContent_anno.xml")
Resource res;
public void parse() throws DocumentException, IOException{
System.out.println(res.getFilename());
System.out.println(res.getDescription());
SAXReader read=new SAXReader();
Document doc=read.read(res.getFile());
Element root=doc.getRootElement();
List list=root.elements();
for (Iterator it=list.iterator(); it.hasNext();) {
Element book=it.next();
List ll=book.elements();
System.out.println(book.getName());
for (Iterator it2=ll.iterator(); it2.hasNext();) {
Element book1=it2.next();
System.out.println(book1.getName());
System.out.println(book1.getText());
}
}
}
public Resource getRes() {
return res;
}
public void setRes(Resource res) {
this.res = res;
}
}
//可以使用 spring配置文件 给 Resource 赋值
[b] 在ApplicatoinContext中使用资源[/b]
//第一种方式
1.使用ClassPathXmlApplicationContext 对应ClassPathResource
2.使用FileSystemXmlApplicationContext 对应 FileSystemResource
3.使用XmlWebApplicationContext :对应 ServletContextResource
ApplicatoinContext act=new FileSystemXmlApplicationContext("bean.xml");
//第二中方式 采用前缀访问策略
ApplicatoinContext act=new FileSystemXmlApplicationContext("classpath:bean.xml");
//这样就强制转换为ClassPathResource 来加载配置文件了
//第三种方式 使用classpath*: 前缀
//classpath*
ApplicatoinContext act=new FileSystemXmlApplicationContext("classpath*:bean.xml");
ApplicatoinContext act=new FileSystemXmlApplicationContext("classpath*:bean*.xml");
//和classpath的区别是 classpath*:可以加载多个资源文件 ,classpath只能加载一个资源文件
//第四种方式 使用file:前缀
//表面上一个是相对路径,一个绝对路径 其实 FileSystemXmlApplicationContext会将所有的FileSystemResource 实例 当成 相对路径来处理.
ApplicatoinContext act=new FileSystemXmlApplicationContext("bean.xml");
ApplicatoinContext act=new FileSystemXmlApplicationContext("/bean.xml");
//如果非要区分 相对路径 和绝对路径
ApplicatoinContext act=new FileSystemXmlApplicationContext("file:bean.xml");
ApplicatoinContext act=new FileSystemXmlApplicationContext("file:/bean.xml");