java解析xml

我就是我 2023-06-07 03:16 14阅读 0赞

1.DOM方式解析XML  
Dom解析是将xml文件全部载入到内存，组装成一颗dom树，然后通过节点以及节点之间的关系来解析xml文件,与平台无关,java提供的一种基础的解析XML文件的API,理解较简单，但是由于整个文档都需要载入内存,不适用于文档较大时。

2.SAX方式解析XML  
基于事件驱动,逐条解析,适用于只处理xml数据，不易编码,而且很难同时访问同一个文档中的多处不同数据

3.JDOM方式解析XML  
简化与XML的交互并且比使用DOM实现更快,仅使用具体类而不使用接口因此简化了API,并且易于使用

4.DOM4j方式解析XML  
JDOM的一种智能分支,功能较强大，建议熟练使用

下面贴出第四种方式DOM4j的具体使用：  
需要解析的xml：

<?xml version="1.0" encoding="UTF-8"?>
    <bookstore>
        <book id="1">
            <name>冰与火之歌</name>
            <author>乔治马丁</author>
            <year>2014</year>
            <price>89</price>
        </book>
        <book id="2">
            <name>安徒生童话</name>
            <author>安徒生</author>
            <year>2004</year>
            <price>77</price>
        </book>
        <book id="3">
            <name>think think think</name>
            <author>aaa</author>
            <year>1997</year>
            <price>100</price>
        </book>
    </bookstore>

工程中引入以下依赖：

<dependency>
                <groupId>dom4j</groupId>
                <artifactId>dom4j</artifactId>
                <version>1.6.1</version>
            </dependency>
    
            <dependency>
                <groupId>com.alibaba</groupId>
                <artifactId>fastjson</artifactId>
                <version>1.2.62</version>
            </dependency>

创建几个bean对象用于存储数据：

package com.qs.bean;
    public class Book { 
        private Integer id;
        private String name;
        private String author;
        private Integer year;
        private double price;
    
        public Integer getId() { 
            return id;
        }
    
        public void setId(Integer id) { 
            this.id = id;
        }
    
        public String getName() { 
            return name;
        }
    
        public void setName(String name) { 
            this.name = name;
        }
    
        public String getAuthor() { 
            return author;
        }
    
        public void setAuthor(String author) { 
            this.author = author;
        }
    
        public Integer getYear() { 
            return year;
        }
    
        public void setYear(Integer year) { 
            this.year = year;
        }
    
        public double getPrice() { 
            return price;
        }
    
        public void setPrice(double price) { 
            this.price = price;
        }
    }

package com.qs.beanxml;
    
    import com.qs.bean.Book;
    
    import java.util.List;
    
    public class BookStore { 
        private List<Book> bookstore;
    
        public List<Book> getBookstore() { 
            return bookstore;
        }
        
        public void setBookstore(List<Book> bookstore) { 
            this.bookstore = bookstore;
        }
    }

package com.qs.parsexml;
    
    import com.alibaba.fastjson.JSON;
    import com.alibaba.fastjson.JSONArray;
    import com.qs.bean.Book;
    import com.qs.beanxml.BookStore;
    import org.dom4j.Attribute;
    import org.dom4j.Document;
    import org.dom4j.DocumentException;
    import org.dom4j.Element;
    import org.dom4j.io.SAXReader;
    
    import java.io.File;
    import java.util.ArrayList;
    import java.util.Iterator;
    import java.util.List;
    
    /** * 用DOM4J方法解析xml文件 * */
    public class ParseXmlByDom4j { 
        public static BookStore parseBookStoreXML(File file) { 
            SAXReader reader = new SAXReader();
            BookStore bookStore = new BookStore();
            try { 
                //获取操作文档对象
                Document document = reader.read(file);
                Element rootElement = document.getRootElement();
                //获取这个元素直接子节点的迭代器
                Iterator it = rootElement.elementIterator();
                //开始解析rootElement下的内容
                List<Book> bookList = new ArrayList<>();
                Book book = null;
                while (it.hasNext()) { 
                    book = new Book();
                    Element bookElement = (Element) it.next();
                    //遍历bookElement的所有属性
                    List<Attribute> attributes = bookElement.attributes();
                    for (Attribute attribute : attributes) { 
                        if (attribute.getName().equals("id")) { 
                            String id = attribute.getValue();
                            book.setId(Integer.parseInt(id));
                        }
                    }
                    Iterator bookit = bookElement.elementIterator();
                    while (bookit.hasNext()) { 
                        Element next = (Element) bookit.next();
                        String nodeName = next.getName();
                        String value = next.getStringValue();
                        if ("name".equals(nodeName)) { 
                            book.setName(value);
                        } else if ("author".equals(nodeName)) { 
                            book.setAuthor(value);
                        } else if ("year".equals(nodeName)) { 
                            book.setYear(Integer.parseInt(value));
                        } else if ("price".equals(nodeName)) { 
                            book.setPrice(Double.parseDouble(value));
                        }
                    }
                    bookList.add(book);
                }
                bookStore.setBookstore(bookList);
            } catch (DocumentException e) { 
                e.printStackTrace();
                return null;
            }
            return bookStore;
        }
    
        public static void main(String[] args) { 
            //注意此处是实际文件的路径
            BookStore bookStore = parseBookStoreXML(new File("E:/IDEWorkSpace/IdeaWorkSpace/MyWorkSpace/java_xml/doc/books.xml"));
            System.out.println(JSON.toJSONString(bookStore));
        }
    }

上个文件改进之后：

package com.qs.parsexml;
    
    import com.alibaba.fastjson.JSON;
    import com.qs.bean.Book;
    import com.qs.beanxml.BookStore;
    import org.dom4j.Attribute;
    import org.dom4j.Document;
    import org.dom4j.DocumentException;
    import org.dom4j.Element;
    import org.dom4j.io.SAXReader;
    
    import java.io.File;
    import java.util.ArrayList;
    import java.util.Iterator;
    import java.util.List;
    
    /** * 用DOM4J方法读取xml文件 * (将上个文件重新封装改进了一下) */
    public class ParseXmlByDom4j { 
        public static BookStore parseBookStoreXML(File file) { 
            SAXReader reader = new SAXReader();
            BookStore bookStore = new BookStore();
            try { 
                //获取操作文档对象
                Document document = reader.read(file);
                Element rootElement = document.getRootElement();
                //获取这个元素直接子节点的迭代器
                Iterator it = rootElement.elementIterator();
                //开始解析rootElement下的内容
                List<Book> bookList = new ArrayList<>();
                Book book = null;
                while (it.hasNext()) { 
                    book = new Book();
                    Element bookElement = (Element) it.next();
                    //指定获取某个元素的属性值
                    String bookId = getValueByAttribute(bookElement, "id");
                    //设置bookId
                    if (bookId != null) { 
                        book.setId(Integer.parseInt(bookId));
                    }
                    //指定获取book标签下的子标签的内容
                    String nameValue = getValueByElement(bookElement, "name");
                    String authorValue = getValueByElement(bookElement, "author");
                    String yearValue = getValueByElement(bookElement, "year");
                    String priceValue = getValueByElement(bookElement, "price");
                    //设置book的其他字段
                    book.setName(nameValue);
                    book.setAuthor(authorValue);
                    book.setYear(Integer.parseInt(yearValue));
                    book.setPrice(Double.parseDouble(priceValue));
                    //添加到list中
                    bookList.add(book);
                }
                bookStore.setBookstore(bookList);
            } catch (DocumentException e) { 
                e.printStackTrace();
                return null;
            }
            return bookStore;
        }
    
        //指定获取某个元素的内容
        private static String getValueByElement(Element element, String needElement) { 
            String value = null;
            Iterator it = element.elementIterator();
            while (it.hasNext()) { 
                Element next = (Element) it.next();
                String nodeName = next.getName();
                if (needElement.equals(nodeName)) { 
                    value = next.getStringValue();
                    break;
                }
            }
            return value;
        }
    
        //获取一个节点元素的某个属性值
        private static String getValueByAttribute(Element element, String attribute) { 
            String value = null;
            //遍历bookElement的所有属性
            List<Attribute> attributes = element.attributes();
            for (Attribute attr : attributes) { 
                if (attribute.equals(attr.getName())) { 
                    value = attr.getValue();
                    break;
                }
            }
            return value;
        }
    
    
        public static void main(String[] args) { 
           //注意此处是实际xml文件的存放路径
            BookStore bookStore = parseBookStoreXML(new File("E:/IDEWorkSpace/IdeaWorkSpace/MyWorkSpace/java_xml/doc/books.xml"));
            System.out.println(".................................");
            System.out.println(JSON.toJSONString(bookStore));
        }
    }

输出结果：

{ 
    	"bookstore": [
    		{ 
    			"author": "乔治马丁",
    			"id": 1,
    			"name": "冰与火之歌",
    			"price": 89.0,
    			"year": 2014
    		},
    		{ 
    			"author": "安徒生",
    			"id": 2,
    			"name": "安徒生童话",
    			"price": 77.0,
    			"year": 2004
    		},
    		{ 
    			"author": "aaa",
    			"id": 3,
    			"name": "think think think",
    			"price": 100.0,
    			"year": 1997
    		}
    	]
    }