由ISBN自动获取书籍信息——下载可用

首先需要安装依赖环境，因为代码运行的时候会用到org.apache.http
顺便放一个net.sf.json的依赖包
整理这篇博客的目的是网上的代码有的缺一个类，有的依赖库没给，所以在学的时候费了一番功夫，特此整理。
首先是书本保存的信息类

/**
 * 
 */
package test;

/**
 * @author ly
 *
 */
import java.io.Serializable;

public class TudouBookInfo implements Serializable {
 
  private static final long serialVersionUID = 2179631010054135058L;
 
  private String tags;//书本标签
 
  private String isbn10;//10位ISBN
  
  private String isbn13;
 
  private String title;
 
  private String pages;
 
  private String author;
 
  private String price;
 
  private String binding;
 
  private String publisher;
 
  private String pubdate;
 
  private String summary;
 
  private String imagePath;
 
  /**
   * @return the imagePath
   */
  public String getImagePath() {
    return imagePath;
  }
 
  /**
   * @param imagePath
   *            the imagePath to set
   */
  public void setImagePath(String imagePath) {
    this.imagePath = imagePath;
  }
 
  public TudouBookInfo() {
  }
 
  /**
   * @return the tags
   */
  public String getTags() {
    return tags;
  }
 
  /**
   * @param tags
   *            the tags to set
   */
  public void setTags(String tags) {
    this.tags = tags;
  }
 
  /**
   * @return the isbn10
   */
  public String getIsbn10() {
    return isbn10;
  }
 
  /**
   * @param isbn10
   *            the isbn10 to set
   */
  public void setIsbn10(String isbn10) {
    this.isbn10 = isbn10;
  }
 
  /**
   * @return the isbn13
   */
  public String getIsbn13() {
    return isbn13;
  }
 
  /**
   * @param isbn13
   *            the isbn13 to set
   */
  public void setIsbn13(String isbn13) {
    this.isbn13 = isbn13;
  }
 
  /**
   * @return the title
   */
  public String getTitle() {
    return title;
  }
 
  /**
   * @param title
   *            the title to set
   */
  public void setTitle(String title) {
    this.title = title;
  }
 
  /**
   * @return the pages
   */
  public String getPages() {
    return pages;
  }
 
  /**
   * @param pages
   *            the pages to set
   */
  public void setPages(String pages) {
    this.pages = pages;
  }
 
  /**
   * @return the author
   */
  public String getAuthor() {
    return author;
  }
 
  /**
   * @param author
   *            the author to set
   */
  public void setAuthor(String author) {
    this.author = author;
  }
 
  /**
   * @return the price
   */
  public String getPrice() {
    return price;
  }
 
  /**
   * @param price
   *            the price to set
   */
  public void setPrice(String price) {
    this.price = price;
  }
 
  /**
   * @return the binding
   */
  public String getBinding() {
    return binding;
  }
 
  /**
   * @param binding
   *            the binding to set
   */
  public void setBinding(String binding) {
    this.binding = binding;
  }
 
  /**
   * @return the publisher
   */
  public String getPublisher() {
    return publisher;
  }
 
  /**
   * @param publisher
   *            the publisher to set
   */
  public void setPublisher(String publisher) {
    this.publisher = publisher;
  }
 
  /**
   * @return the pubdate
   */
  public String getPubdate() {
    return pubdate;
  }
 
  /**
   * @param pubdate
   *            the pubdate to set
   */
  public void setPubdate(String pubdate) {
    this.pubdate = pubdate;
  }
 
  /**
   * @return the summary
   */
  public String getSummary() {
    return summary;
  }
 
  /**
   * @param summary
   *            the summary to set
   */
  public void setSummary(String summary) {
    this.summary = summary;
  }
 
}

写一个XML的解析类
通过ISBN查询得到的信息以XML格式的形式返回，所以写一个针对此类XML格式解析的类才能得到我们想要的具体的信息（如：标题，作者，简介等等）。

/**
 * 
 */
package test;

/**
 * @author ly
 *
 */
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
 
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;
 
import org.xml.sax.Attributes;
import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.xml.sax.helpers.DefaultHandler;
 
 
public class BookXMLParser extends DefaultHandler {
 
  private TudouBookInfo book = null;
 
  private final StringBuilder buff = new StringBuilder();
  private String attname = null;
  private final List tags = new ArrayList();
 
  /**
   * @return the book
   */
  public TudouBookInfo getBook() {
    return book;
  }
 
  public BookXMLParser(InputStream is) {
    try {
      SAXParserFactory spfactory = SAXParserFactory.newInstance();
      spfactory.setValidating(false);
      SAXParser saxParser = spfactory.newSAXParser();
      XMLReader xmlReader = saxParser.getXMLReader();
      xmlReader.setContentHandler(this);
      xmlReader.parse(new InputSource(is));
    } catch (Exception e) {
      System.err.println(e);
      System.exit(1);
    }
  }
 
  public void startElement(String uri, String localName, String name,
      Attributes atts) throws SAXException {
    if (name.equalsIgnoreCase("entry")) {
      book = new TudouBookInfo();
    } else if (name.equalsIgnoreCase("db:attribute")) {
      attname = atts.getValue("name");
    } else if (name.equalsIgnoreCase("db:tag")) {
      tags.add(atts.getValue("name"));
    } else if (name.equalsIgnoreCase("link")) {
      if ("image".equalsIgnoreCase(atts.getValue("rel"))) {
        book.setImagePath(atts.getValue("href"));
      }
    }
    buff.setLength(0);
  }
 
  public void endElement(String uri, String localName, String name)
      throws SAXException {
    if ("entry".equalsIgnoreCase(name)) {
      StringBuilder str = new StringBuilder();
      for (String t : tags) {
        str.append(t + "/");
      }
      book.setTags(str.toString());
    } else if (name.equalsIgnoreCase("db:attribute")) {
      String value = buff.toString().trim();
      if ("isbn10".equalsIgnoreCase(attname)) {
        book.setIsbn10(value);
      } else if ("isbn13".equalsIgnoreCase(attname)) {
        book.setIsbn13(value);
      } else if ("title".equalsIgnoreCase(attname)) {
        book.setTitle(value);
      } else if ("pages".equalsIgnoreCase(attname)) {
        book.setPages(value);
      } else if ("author".equalsIgnoreCase(attname)) {
        book.setAuthor(value);
      } else if ("price".equalsIgnoreCase(attname)) {
        book.setPrice(value);
      } else if ("publisher".equalsIgnoreCase(attname)) {
        book.setPublisher(value);
      } else if ("binding".equalsIgnoreCase(attname)) {
        book.setBinding(value);
      } else if ("pubdate".equalsIgnoreCase(attname)) {
        book.setPubdate(value);
      }
    } else if ("summary".equalsIgnoreCase(name)) {
      book.setSummary(buff.toString());
    }
    buff.setLength(0);
  }
 
  public void characters(char ch[], int start, int length)
      throws SAXException {
    buff.append(ch, start, length);
  }
 
}

**最后写一个测试类 **

/**
 * 
 */
package test;

/**
 * @author ly
 *
 */
import java.io.IOException;
import java.io.InputStream;
 
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
 
public class RetrieveDocumentByURL {
  
  public RetrieveDocumentByURL(String url) throws ClientProtocolException, IOException{
    DefaultHttpClient client = new DefaultHttpClient();
    HttpGet get = new HttpGet(url);
    HttpResponse response = client.execute(get);
        HttpEntity entity = response.getEntity();
        InputStream is = entity.getContent();
        TudouBookInfo book = new BookXMLParser(is).getBook();
        System.out.println("title:->" + book.getTitle());
        System.out.println("summary:->"+ book.getSummary());
        System.out.println("price:-->" + book.getPrice());
        System.out.println("author:-->" + book.getAuthor());
        System.out.println("ImagePath:-->" + book.getImagePath());
  }
  public static void main(String[] args) throws ClientProtocolException, IOException {
    new RetrieveDocumentByURL("http://api.douban.com/book/subject/isbn/9787121194276");
  }
 
}

最后，如何自动获得ISBN呢？其实用QQ,微信的扫一扫对着ISBN的二维码扫一下就可以实现，但是QQ扫出来是一串ISBN号，而微信扫出来是完整的书籍信息