介绍

Hutool封装了Bean的信息描述来将一个Bean的相关信息全部通过反射解析出来，此类类似于JDK的BeanInfo，也可以理解为是这个类的强化版本。

BeanDesc包含所有字段（属性）及对应的Getter方法和Setter方法，与BeanInfo不同的是，BeanDesc要求属性和getter、setter必须严格对应，即如果有非public属性，它没有对应的getter，则不能获取属性值，没有setter则不能注入属性值。

属性和getter、setter关联规则如下：

1. 忽略字段和方法名的大小写（匹配时）
2. 字段名是XXX，则Getter查找getXXX、isXXX、getIsXXX
3. 字段名是XXX，Setter查找setXXX、setIsXXX
4. Setter忽略参数值与字段值类型不匹配的情况，因此有多个参数类型的重载时，会调用首次匹配的

使用

我们定义一个较为复杂的Bean：

public static class User {
    private String name;
    private int age;
    private boolean isAdmin;
    private boolean isSuper;
    private boolean gender;
    private Boolean lastPage;
    private Boolean isLastPage;

    public String getName() {
        return name;
    }

    public void setName(final String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public User setAge(final int age) {
        this.age = age;
        return this;
    }

    public String testMethod() {
        return "test for " + this.name;
    }

    public boolean isAdmin() {
        return isAdmin;
    }

    public void setAdmin(final boolean isAdmin) {
        this.isAdmin = isAdmin;
    }

    public boolean isIsSuper() {
        return isSuper;
    }

    public void setIsSuper(final boolean isSuper) {
        this.isSuper = isSuper;
    }

    public boolean isGender() {
        return gender;
    }

    public void setGender(final boolean gender) {
        this.gender = gender;
    }

    public Boolean getIsLastPage() {
        return this.isLastPage;
    }

    public void setIsLastPage(final Boolean isLastPage) {
        this.isLastPage = isLastPage;
    }

    public Boolean getLastPage() {
        return this.lastPage;
    }

    public void setLastPage(final Boolean lastPage) {
        this.lastPage = lastPage;
    }

    @Override
    public String toString() {
        return "User [name=" + name + ", age=" + age + ", isAdmin=" + isAdmin + ", gender=" + gender + "]";
    }
}

字段get/Set方法获取

一般字段

public void propDescTes() {
    final BeanDesc desc = BeanUtil.getBeanDesc(User.class);
    Assertions.assertEquals("User", desc.getSimpleName());

    Assertions.assertEquals("age", desc.getField("age").getName());
    Assertions.assertEquals("getAge", desc.getGetter("age").getName());
    Assertions.assertEquals("setAge", desc.getSetter("age").getName());
    Assertions.assertEquals(1, desc.getSetter("age").getParameterTypes().length);
    Assertions.assertSame(int.class, desc.getSetter("age").getParameterTypes()[0]);
}

Boolean字段

我们会发现User中的boolean字段叫做isAdmin，此时同名的getter也可以获取到：

public void propDescOfBooleanTest() {
    final BeanDesc desc = BeanUtil.getBeanDesc(User.class);

    Assertions.assertEquals("isAdmin", desc.getGetter("isAdmin").getName());
    Assertions.assertEquals("setAdmin", desc.getSetter("isAdmin").getName());
    Assertions.assertEquals("isGender", desc.getGetter("gender").getName());
    Assertions.assertEquals("setGender", desc.getSetter("gender").getName());
}

当然，用户如果觉得isIsXXX才是正确的，BeanDesc也可以完美获取，我们以isSuper字段为例：

public void propDescOfBooleanTest2() {
    final BeanDesc desc = BeanUtil.getBeanDesc(User.class);
    // isIsSuper
    Assertions.assertEquals("isIsSuper", desc.getGetter("isSuper").getName());
    Assertions.assertEquals("setIsSuper", desc.getSetter("isSuper").getName());
}

字段属性赋值

public void getSetTest() {
    final BeanDesc desc = BeanUtil.getBeanDesc(User.class);

    final User user = new User();
    desc.getProp("name").setValue(user, "张三");
    Assertions.assertEquals("张三", user.getName());

    final Object value = desc.getProp("name").getValue(user);
    Assertions.assertEquals("张三", value);
}