Commons BeanUtils

一）此包的下载 
    http://commons.apache.org/beanutils/download_beanutils.cgi  此包目前最新的版本是1.8.3 

二）此包的功能 
    用于处理JavaBeans。它利用Java的反射机制，从动态的生成对bean的getter和setter的调用代码，到模拟创建一个动态的bean，等等。这个包看似简单，却是很多开源项目的基石：如在著名的Struts和Spring Framework中，我们都能找到BeanUtils的影子。 

三）此包的API 
    http://commons.apache.org/beanutils/v1.8.3/apidocs/index.html 

    从 1.7.0 版本开始 BeanUtils被细分成3种架包: 
    commons-beanutils.jar - 包含所有BeanUtils内容的架包 
    commons-beanutils-core.jar - 除去Collections内容的架包 
    commons-beanutils-bean-collections.jar - 仅有Collections内容的架包（此部分内容依赖于Commons Collections ） 

四）常用类： 
    DynaBean -- 该接口定义的是一个动态的JavaBean，它的属性类型、名称和值都是可以动态改变的。 
    DynaClass -- 该接口定义的是针对实现了DynaBean接口的类的java.lang.Class对象，提供如getName()、newInstance()等方法。 
    DynaProperty -- 用于描述DynaBean的属性 

五）代码样例 
Java代码  
 /** Address.java */  
package sean.study.commons.beanutils;  
   
public class Address {  
    private String zipCode;  
    private String addr;  
    private String city;  
    private String country;  
   
    public Address() {}  
    public Address(String zipCode, String addr, String city, String country) {  
        this.zipCode = zipCode;  
        this.addr = addr;  
        this.city = city;  
        this.country = country;  
    }  
    public String getAddr() {  
        return addr;  
    }  
    public void setAddr(String addr) {  
        this.addr = addr;  
    }  
    public String getCity() {  
        return city;  
    }  
    public void setCity(String city) {  
        this.city = city;  
    }  
    public String getCountry() {  
        return country;  
    }  
    public void setCountry(String country) {  
        this.country = country;  
    }  
    public String getZipCode() {  
        return zipCode;  
    }  
    public void setZipCode(String zipCode) {  
        this.zipCode = zipCode;  
    }  
   
}  
   
/** Customer.java */  
package sean.study.commons.beanutils;  
   
public class Customer {  
    private long id;  
    private String name;  
    private Address[] addresses;  
   
    public Customer() {}  
    public Customer(long id, String name, Address[] addresses) {  
        this.id = id;  
        this.name = name;  
        this.addresses = addresses;  
    }  
    public Address[] getAddresses() {  
        return addresses;  
    }  
    public void setAddresses(Address[] addresses) {  
        this.addresses = addresses;  
    }  
    public long getId() {  
        return id;  
    }  
    public void setId(long id) {  
        this.id = id;  
    }  
    public String getName() {  
        return name;  
    }  
    public void setName(String name) {  
        this.name = name;  
    }  
}  



我们来看看通常我们是怎样利用Commons BeanUtils来完成一些基本的JavaBean和DynaBean操作： 
Java代码  
package sean.study.commons.beanutils;  
   
import org.apache.commons.beanutils.BasicDynaBean;  
import org.apache.commons.beanutils.BasicDynaClass;  
import org.apache.commons.beanutils.DynaBean;  
import org.apache.commons.beanutils.DynaProperty;  
import org.apache.commons.beanutils.PropertyUtils;  
import org.apache.commons.lang.StringUtils;  
   
public class BeanUtilsUsage {  
   
    public static void main(String[] args) throws Exception {  
        demoNormalJavaBeans();  
        demoDynaBeans();  
    }  
   
    public static void demoNormalJavaBeans() throws Exception {  
   
        System.out.println(StringUtils.center(" demoNormalJavaBeans ", 40, "="));  
         
        // data setup  
        Address addr1 = new Address("CA1234", "xxx", "Los Angeles", "USA");  
        Address addr2 = new Address("100000", "xxx", "Beijing", "China");  
        Address[] addrs = new Address[2];  
        addrs[0] = addr1;  
        addrs[1] = addr2;  
        Customer cust = new Customer(123, "John Smith", addrs);  
         
        // accessing the city of first address  
        String cityPattern = "addresses[0].city";  
        String name = (String) PropertyUtils.getSimpleProperty(cust, "name");  
        String city = (String) PropertyUtils.getProperty(cust, cityPattern);  
        Object[] rawOutput1 = new Object[] { "The city of customer ", name,  
                "'s first address is ", city, "." };  
        System.out.println(StringUtils.join(rawOutput1));  
         
        // setting the zipcode of customer's second address  
        String zipPattern = "addresses[1].zipCode";  
        if (PropertyUtils.isWriteable(cust, zipPattern)) {//PropertyUtils  
            System.out.println("Setting zipcode ...");  
            PropertyUtils.setProperty(cust, zipPattern, "200000");//PropertyUtils  
        }  
        String zip = (String) PropertyUtils.getProperty(cust, zipPattern);//PropertyUtils  
        Object[] rawOutput2 = new Object[] { "The zipcode of customer ", name,  
                "'s second address is now ", zip, "." };  
        System.out.println(StringUtils.join(rawOutput2));  
         
        System.out.println();  
    }  
   
    public static void demoDynaBeans() throws Exception {  
   
        System.out.println(StringUtils.center(" demoDynaBeans ", 40, "="));  
         
        // creating a DynaBean  
        DynaProperty[] dynaBeanProperties = new DynaProperty[] {//DynaProperty  
                new DynaProperty("name", String.class),  
                new DynaProperty("inPrice", Double.class),   
                new DynaProperty("outPrice", Double.class),  
        };  
        BasicDynaClass cargoClass = new BasicDynaClass("Cargo", BasicDynaBean.class, dynaBeanProperties); //BasicDynaClass  BasicDynaBean  
        DynaBean cargo = cargoClass.newInstance();//DynaBean  
         
        // accessing a DynaBean  
        cargo.set("name", "Instant Noodles");  
        cargo.set("inPrice", new Double(21.3));  
        cargo.set("outPrice", new Double(23.8));  
        System.out.println("name: " + cargo.get("name"));  
        System.out.println("inPrice: " + cargo.get("inPrice"));  
        System.out.println("outPrice: " + cargo.get("outPrice"));  
   
        System.out.println();  
    }  
}  


上述代码运行结果如下： 

========= demoNormalJavaBeans ========== 
The city of customer John Smith's first address is Los Angeles. 
Setting zipcode ... 
The zipcode of customer John Smith's second address is now 200000. 

============ demoDynaBeans ============= 
name: Instant Noodles 
inPrice: 21.3 
outPrice: 23.8