JAVA工具包_BeanUtils

Posted 2020-10-05

简介

大多数的java开发者通常在创建Java类的时候都会遵循JavaBean的命名模式，对类的属性生成getters方法和setters方法。通过调用相应的getXxx和setXxx方法，直接访问这些方法是很常见的做法。BeanUtils就是一种方便我们对JavaBean进行操作的工具，是Apache组织下的产品。

前提

• commons-beanutils-1.9.3.jar
• commons-logging-1.2.jar(由于commons-beanutils-1.9.3.jar依赖与commons-loggin否则会报错：Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/logging/LogFactory)

代码清单，测试用的JavaBean:User.java

public class User {

    // 姓名
    private String userName;

    // 年龄
    private int age;

    // 生日
    private Date birthday;

    public User() {
    }

    public User(String userName, int age) {
        this.userName = userName;
        this.age = age;
    }

    public User(String userName, int age, Date birthday) {
        this.userName = userName;
        this.age = age;
        this.birthday = birthday;
    }

    public int getAge() {
        return this.age;
    }

    public String getUserName() {
        return this.userName;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public Date getBirthday() {
        return birthday;
    }

    public void setBirthday(Date birthday) {
        this.birthday = birthday;
    }

    @Override
    public String toString() {
        return "User [userName=" + userName + ", age=" + age + ", birthday=" + birthday + "]";
    }

}

测试代码清单

public class BeanUtilsDemo {

    public static void main(String[] args) throws Exception {
        User user = new User("Jim", 1, new Date(123456798));
        // 获取属性值
        System.out.println("userName :" + BeanUtils.getProperty(user, "userName"));
        // 设置引用类型属性
        BeanUtils.setProperty(user, "userName", "testBeanUtils");
        System.out.println("user = " + user);
        // 设置对象类型属性方法一
        BeanUtils.setProperty(user, "birthday", new Date(987652122564L));
        System.out.println("user = " + user);
        // 设置对象类型属性方法二
        BeanUtils.setProperty(user, "birthday.time", 45641246546L);
        System.out.println("user = " + user);
        // 设置自定义对象属性方法一
        System.out.println("WayOne \n Before:\n" + user);
        Hobby hobby = new Hobby("篮球", "每天一小时，健康一辈子");
        BeanUtils.setProperty(user, "hobby", hobby);
        System.out.println("After:\n" + user);
        // 设置自定义对象属性方法二,这里需要注意，如果hobby为null，
        // 则这样是设置值是设置不进去的，只有当对象不为空的时候才能设置进去
        System.out.println("WayTwo \n Before:\n" + user);
        BeanUtils.setProperty(user, "hobby.hobbyName", "乒乓球");
        System.out.println("user = " + user);
        BeanUtils.setProperty(user, "hobby", null);
        BeanUtils.setProperty(user, "hobby.desc", "我国乒乓第一，我爱国");
        System.out.println("After:\n" + user);
    
    }

}