利用java反射根据map的key-value为一个类是实例赋值_map<k,value> key为订单号,value赋值一个类-优快云博客

本文链接：https://blog.youkuaiyun.com/qq_36709020/article/details/104609724

本文介绍了如何使用Java反射机制，通过Map的键值对来为类的public和private属性进行赋值。示例中展示了对于public属性直接操作，而对于private属性则需要借助公共setter方法。

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1、public 属性

Person 类

public class Person {
    public int age = 0;
    public String name = "helloword";
    public int id = 1234;

    public int getAge() {
        return age;
    }

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

    public String getName() {
        return name;
    }

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

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }
}

Test 类

public class Test {

    public static void main(String[] args) {

        //这么做的前期是  Person的属性必须是 public的
        Person person = new Person();
        System.out.println("-------------------赋值前---------------------------");
        System.out.println(person.getName());   //helloword
        System.out.println(person.getAge());   //0
        System.out.println(person.getId());   //1234
        //用于储值的map对象
        Map map = new HashMap();
        map.put("name", "张三");
        map.put("age", 18);
        //取得该对象反射的 Fields
        Field[] declaredFields = person.getClass().getDeclaredFields();
        for (Field f : declaredFields) {
            String perName = f.getName();
            Object o = map.get(perName);
            if (o != null) {
                try {
                    f.set(person, o);
                } catch (IllegalAccessException e) {
                    e.printStackTrace();
                }
            }
        }
        System.out.println("-------------------赋值后---------------------------");
        System.out.println(person.getName());   //张三
        System.out.println(person.getAge());   //18
        System.out.println(person.getId());   //1234
    }
}

2、private 属性，须借助与该类的public setter

Person类

public class Person {
    private int age = 0;
    private String name = "helloword";
    priavte int id = 1234;

    public int getAge() {
        return age;
    }

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

    public String getName() {
        return name;
    }

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

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }
}

Test类

public class Test {

    public static void main(String[] args) {

        Person person = new Person();
        System.out.println("-------------------赋值前---------------------------");
        System.out.println(person.getName());   //helloword
        System.out.println(person.getAge());   //0
        System.out.println(person.getId());   //1234
        //用于储值的map对象
        Map map = new HashMap();
        map.put("name", "张三");
        map.put("age", 18);
        //取得该对象反射的 Fields
        Class Person = person.getClass();
        Field[] declaredFields = Person.getDeclaredFields();
        //用于存储method的
        Map<String,Method> mapMethod = new HashMap();
        try {
            Method[] declaredMethods = Person.getDeclaredMethods();
            //将method放入mapMethod 中方便下面调用
            for(Method m : declaredMethods){
                mapMethod.put(m.getName().toLowerCase(),m);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        for (Field f : declaredFields) {
            String perName = f.getName();
            Object o = map.get(perName);
            if (o != null) {
                try {
                    mapMethod.get("set"+perName.toLowerCase()).invoke(person,o);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }
        System.out.println("-------------------赋值后---------------------------");
        System.out.println(person.getName());   //张三
        System.out.println(person.getAge());   //18
        System.out.println(person.getId());   //1234
    }
}