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JXPath 提供了使用 Xpath 语法操纵符合 Java 类命名规范的 JavaBeans 的工具。也支持 maps、DOM 和其他对象模型。对于深层次结构的 JavaBean，使用 JXPath 可以方便地访问深层次的属性，而免去了繁琐的 getter/setter 操作。
以下面的 JavaBeans 为例。
package com.huey.jxpath; import lombok.AllArgsConstructor; import lombok.Data; import lombok.NoArgsConstructor; @Data @NoArgsConstructor @AllArgsConstructor public class Book { private String title; private Author[] authors; private Publisher publisher; private String isbn; private double price; }
package com.huey.jxpath; import java.util.Date; import lombok.AllArgsConstructor; import lombok.Data; import lombok.NoArgsConstructor; @Data @NoArgsConstructor @AllArgsConstructor public class Author { private String firstName; private String lastName; private char gender; private Date birthday; }
package com.huey.jxpath; import java.util.Map; import lombok.AllArgsConstructor; import lombok.Data; import lombok.NoArgsConstructor; @Data @NoArgsConstructor @AllArgsConstructor public class Publisher { private String name; private String address; private Map<String, String> contacts; }
初始化
Author[] authors; Publisher publisher; Book book; authors = new Author[] { new Author("Eric", "Freeman", ‘F‘, new Date()), new Author("ElElisabeth", "Freeman", ‘M‘, new Date()) }; Map<String, String> contacts = new HashMap<String, String>(); contacts.put("tel", "010－12345678"); contacts.put("fax", "010－87654321"); contacts.put("email", "test@163.com"); publisher = new Publisher("中国电力出版社", "北京市XX区YY路Z号", contacts); book = new Book("Head First Design Patterns", authors, publisher, "9787508353937", 98.0);
JavaBean Property Access
JXPathContext context = JXPathContext.newContext(book); String title = (String) context.getValue("title"); Publisher publisher = (Publisher) context.getValue("publisher");
Lenient Mode
当提供的 xpath 无法映射到 JavaBean 的属性时，context.getValue(xpath) 方法会抛出一个异常；而如果调用方法 context.setLenient(true)，则会返回 null。
Nested Bean Property Access
JXPathContext context = JXPathContext.newContext(book); String pName = (String)context.getValue("publisher/name"); char aGender = (Character)context.getValue("authors[firstName=‘Eric‘]/gender");
Collection Subscripts
JXPathContext context = JXPathContext.newContext(book); Author author = (Author) context.getValue("authors[1]"); // 集合第一个元素的下标是 1 而不是 0
Retrieving Multiple Results
JXPathContext context = JXPathContext.newContext(book); Iterator<?> authors = context.iterate("authors"); while (authors.hasNext()) { Author author = (Author) authors.next(); // ... }
Map Element Access
JXPathContext context = JXPathContext.newContext(publisher); String tel = (String) context.getValue("contacts/tel"); String fax = (String) context.getValue("contacts[@name=‘fax‘]");
JXPath(1.3) - Object Graph Traversal
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原文地址：http://www.cnblogs.com/huey/p/4695448.html
