设置多种数据类型，级联对象实例化，级联属性赋值

 

一个简单Java类中的属性类型不仅仅只有String，还会包含有整数、浮点数、日期等，本课程主要讲解如何实现多种数据类型的赋值以及转换处理操作。
一个类可以与其它类发生引用关系，以描述彼此之间的关系，这样的级联结构中就需要考虑对象实例化问题，本课程主要讲解如何在多级VO配置关系时如何通过反射技术实现动态实例化对象操作。
类引用定义之后就会存在有其它引用类型的属性赋值操作，本课程主要讲解多级实例化对象属性内容的获取与其属性设置。

package com.twitter.demo;

import java.util.Date;
import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.text.ParseException;
import java.text.SimpleDateFormat;

class Company{
    private String name;
    private Date createdate;
    public String getName() {
        return this.name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Date getCreatedate() {
        return this.createdate;
    }
    public void setCreatedate(Date createdate) {
        this.createdate = createdate;
    }
}

class Dept{
    private String dname;
    private String loc;
    private Company company;
    public String getDname() {
        return dname;
    }
    public void setDname(String dname) {
        this.dname = dname;
    }
    public String getLoc() {
        return loc;
    }
    public void setLoc(String loc) {
        this.loc = loc;
    }
    public Company getCompany() {
        return company;
    }
    public void setCompany(Company company) {
        this.company = company;
    }
}

class Emp{
    private String ename;
    private String job;
    private Double salary;
    private Integer age;
    private Date hiredate;
    private Dept dept;
    public String getEname() {
        return ename;
    }
    public void setEname(String ename) {
        this.ename = ename;
    }
    public String getJob() {
        return job;
    }
    public void setJob(String job) {
        this.job = job;
    }
    public Double getSalary() {
        return salary;
    }
    public void setSalary(Double salary) {
        this.salary = salary;
    }
    public Integer getAge() {
        return age;
    }
    public void setAge(Integer age) {
        this.age = age;
    }
    public Date getHiredate() {
        return hiredate;
    }
    public void setHiredate(Date hiredate) {
        this.hiredate = hiredate;
    }
    public Dept getDept() {
        return dept;
    }
    public void setDept(Dept dept) {
        this.dept = dept;
    }
}

class BeanUtils{
    private BeanUtils() {}
    public static void setValue(Object obj,String value) {
        String results[] = value.split("\\|");
        for(int x=0;x<results.length;x++) {
            String attval[] = results[x].split(":");
            try {
                if(attval[0].contains(".")) {
                    String temp[] = attval[0].split("\\.");
                    Object currentObject = obj;
                    for(int y=0;y<temp.length-1;y++) {
                        Method getMethod = currentObject.getClass().getDeclaredMethod("get" + StringUtils.initcap(temp[y]));
                        Object tempObject = getMethod.invoke(currentObject);
                        if(tempObject == null) {
                            Field field = currentObject.getClass().getDeclaredField(temp[y]);
                            Method method = currentObject.getClass().getDeclaredMethod("set"+StringUtils.initcap(temp[y]), field.getType());
                            Object newObject = field.getType().getDeclaredConstructor().newInstance();
                            method.invoke(currentObject, newObject);
                            currentObject = newObject;
                        }else {
                            currentObject = tempObject;
                        }
                    }
                }else {
                    Field field = obj.getClass().getDeclaredField(attval[0]);
                    Method setMethod = obj.getClass().getDeclaredMethod("set"+StringUtils.initcap(attval[0]), field.getType());
                    Object convertValue = BeanUtils.convertAtributeValue(field.getType().getName(), attval[1]);
                    setMethod.invoke(obj, convertValue);
                }
            } catch (Exception e) {
                // TODO: handle exception
            }
        }
    }
    
    private static Object convertAtributeValue(String type,String value) {
        if("long".equals(type)||"java.lang.Long".equals(type)) {
            return Long.parseLong(value);
        }else if ("int".equals(type)||"java.lang.Integer".equals(type)) {
            return Integer.parseInt(value);
        }else if ("double".equals(type)||"java.lang.Double".equals(type)) {
            return Double.parseDouble(value);
        }else if ("java.util.Date".equals(type)) {
            SimpleDateFormat sdf = null;
            if(value.matches("\\d{4}-\\d{2}-\\d{2}")) {
                sdf = new SimpleDateFormat("yyyy-MM-dd");
            }else if (value.matches("\\d{4}-\\d{2}-\\d{2} \\d{2}-\\d{2}-\\d{2}")) {
                sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
            }else {
                return new Date();
            }
            try {
                return sdf.parse(type);
            } catch (ParseException e) {
                return new Date();
            }
        }else {
            return value;
        }
    }
}

class StringUtils{
    public static String initcap(String str) {
        if(str == null || "".equals(str)) {
            return str;
        }
        if(str.length() == 1) {
            return str.toUpperCase();
        }else {
            return str.substring(0,1).toUpperCase()+str.substring(1);
        }
    }
}

class ClassInstanceFactory{
    private ClassInstanceFactory() {}
    public static <T> T create(Class<?> clazz,String value) {
        try {
            Object obj = clazz.getDeclaredConstructor().newInstance();
            BeanUtils.setValue(obj, value);
            return (T) obj;
        } catch (Exception e) {
            return null;
        }
        
    }
}

public class JavaReflectDemo {
    public static void main(String[] args) throws Exception{
        String value = "ename:Smith|job:Clerk|salary:8960.00|age:30|hiredate:2003-10-03|"
                +"dept.dname:财务部|dept.company.name:twitter|"
                +"dept.company.createdate:2001-11-11";
        Emp emp = ClassInstanceFactory.create(Emp.class, value);
        System.out.println(emp);
        System.out.println(emp.getDept());
        System.out.println(emp.getDept().getCompany());
    }
}