BeanUtils是apache提供的的一个工具类，在很多地方我们都要用到这个类。下面说说这个类的简单用法。
相关的使用细节已经在代码的注释中说明了。

   @Test      public void test5(){          try {              Person p = new Person(new Book());              //使用beanUtils给对象的属性赋值              BeanUtils.setProperty(p, "username", "张三");              //使用beanUtils获取对象的属性值              System.out.println(BeanUtils.getProperty(p, "username"));              //beanUtils支持属性链赋值与获得值,不过赋值前book要先实例化              BeanUtils.setProperty(p, "book.name", "历史小说");              System.out.println(BeanUtils.getProperty(p, "book.name"));              System.out.println(p.getBook().getName());              //把一个对象的值赋给另一个对象              Person p2 = new Person();              BeanUtils.copyProperties(p2, p);              System.out.println(p2.getUsername()+","+p2.getBook().getName());              Map<String,String> map = new HashMap<String, String>();              //把Map的值拷贝给一个JavaBean              Person p3 = new Person();              map.put("username", "张三");              map.put("password", "9999");              BeanUtils.populate(p3, map );              System.out.println(p3.getUsername()+","+p3.getPassword());          } catch (IllegalAccessException | InvocationTargetException                  | NoSuchMethodException e) {              e.printStackTrace();          }      }

Person.java

public class Person {        private String username;      private String password;      private int money;      private Book book;        public Person() {      }        public Person(Book book) {          this.book = book;      }        public Book getBook() {          return book;      }      public void setBook(Book book) {          this.book = book;      }      public String getUsername() {          return username;      }      public void setUsername(String username) {          this.username = username;      }      public String getPassword() {          return password;      }      public void setPassword(String password) {          this.password = password;      }      public int getMoney() {          return money;      }      public void setMoney(int money) {          this.money = money;      }    }

Book.java

public class Book {        private int id;      private String name;      private int price;      private String author;      private Detail detail;      private Attribute attribute;        public Attribute getAttribute() {          return attribute;      }      public void setAttribute(Attribute attribute) {          this.attribute = attribute;      }      public Detail getDetail() {          return detail;      }      public void setDetail(Detail detail) {          this.detail = detail;      }      public int getId() {          return id;      }      public void setId(int id) {          this.id = id;      }      public String getName() {          return name;      }      public void setName(String name) {          this.name = name;      }      public int getPrice() {          return price;      }      public void setPrice(int price) {          this.price = price;      }      public String getAuthor() {          return author;      }      public void setAuthor(String author) {          this.author = author;      }  }