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。1 package com.twitter.demo; 2 3 import java.util.Date; 4 import java.lang.reflect.Field; 5 import java.lang.reflect.Method; 6 import java.text.ParseException; 7 import java.text.SimpleDateFormat; 8 9 class Company{ 10 private String name; 11 private Date createdate; 12 public String getName() { 13 return this.name; 14 } 15 public void setName(String name) { 16 this.name = name; 17 } 18 public Date getCreatedate() { 19 return this.createdate; 20 } 21 public void setCreatedate(Date createdate) { 22 this.createdate = createdate; 23 } 24 } 25 26 class Dept{ 27 private String dname; 28 private String loc; 29 private Company company; 30 public String getDname() { 31 return dname; 32 } 33 public void setDname(String dname) { 34 this.dname = dname; 35 } 36 public String getLoc() { 37 return loc; 38 } 39 public void setLoc(String loc) { 40 this.loc = loc; 41 } 42 public Company getCompany() { 43 return company; 44 } 45 public void setCompany(Company company) { 46 this.company = company; 47 } 48 } 49 50 class Emp{ 51 private String ename; 52 private String job; 53 private Double salary; 54 private Integer age; 55 private Date hiredate; 56 private Dept dept; 57 public String getEname() { 58 return ename; 59 } 60 public void setEname(String ename) { 61 this.ename = ename; 62 } 63 public String getJob() { 64 return job; 65 } 66 public void setJob(String job) { 67 this.job = job; 68 } 69 public Double getSalary() { 70 return salary; 71 } 72 public void setSalary(Double salary) { 73 this.salary = salary; 74 } 75 public Integer getAge() { 76 return age; 77 } 78 public void setAge(Integer age) { 79 this.age = age; 80 } 81 public Date getHiredate() { 82 return hiredate; 83 } 84 public void setHiredate(Date hiredate) { 85 this.hiredate = hiredate; 86 } 87 public Dept getDept() { 88 return dept; 89 } 90 public void setDept(Dept dept) { 91 this.dept = dept; 92 } 93 } 94 95 class BeanUtils{ 96 private BeanUtils() {} 97 public static void setValue(Object obj,String value) { 98 String results[] = value.split("\\|"); 99 for(int x=0;x<results.length;x++) { 100 String attval[] = results[x].split(":"); 101 try { 102 if(attval[0].contains(".")) { 103 String temp[] = attval[0].split("\\."); 104 Object currentObject = obj; 105 for(int y=0;y<temp.length-1;y++) { 106 Method getMethod = currentObject.getClass().getDeclaredMethod("get" + StringUtils.initcap(temp[y])); 107 Object tempObject = getMethod.invoke(currentObject); 108 if(tempObject == null) { 109 Field field = currentObject.getClass().getDeclaredField(temp[y]); 110 Method method = currentObject.getClass().getDeclaredMethod("set"+StringUtils.initcap(temp[y]), field.getType()); 111 Object newObject = field.getType().getDeclaredConstructor().newInstance(); 112 method.invoke(currentObject, newObject); 113 currentObject = newObject; 114 }else { 115 currentObject = tempObject; 116 } 117 } 118 }else { 119 Field field = obj.getClass().getDeclaredField(attval[0]); 120 Method setMethod = obj.getClass().getDeclaredMethod("set"+StringUtils.initcap(attval[0]), field.getType()); 121 Object convertValue = BeanUtils.convertAtributeValue(field.getType().getName(), attval[1]); 122 setMethod.invoke(obj, convertValue); 123 } 124 } catch (Exception e) { 125 // TODO: handle exception 126 } 127 } 128 } 129 130 private static Object convertAtributeValue(String type,String value) { 131 if("long".equals(type)||"java.lang.Long".equals(type)) { 132 return Long.parseLong(value); 133 }else if ("int".equals(type)||"java.lang.Integer".equals(type)) { 134 return Integer.parseInt(value); 135 }else if ("double".equals(type)||"java.lang.Double".equals(type)) { 136 return Double.parseDouble(value); 137 }else if ("java.util.Date".equals(type)) { 138 SimpleDateFormat sdf = null; 139 if(value.matches("\\d{4}-\\d{2}-\\d{2}")) { 140 sdf = new SimpleDateFormat("yyyy-MM-dd"); 141 }else if (value.matches("\\d{4}-\\d{2}-\\d{2} \\d{2}-\\d{2}-\\d{2}")) { 142 sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); 143 }else { 144 return new Date(); 145 } 146 try { 147 return sdf.parse(type); 148 } catch (ParseException e) { 149 return new Date(); 150 } 151 }else { 152 return value; 153 } 154 } 155 } 156 157 class StringUtils{ 158 public static String initcap(String str) { 159 if(str == null || "".equals(str)) { 160 return str; 161 } 162 if(str.length() == 1) { 163 return str.toUpperCase(); 164 }else { 165 return str.substring(0,1).toUpperCase()+str.substring(1); 166 } 167 } 168 } 169 170 class ClassInstanceFactory{ 171 private ClassInstanceFactory() {} 172 public static <T> T create(Class<?> clazz,String value) { 173 try { 174 Object obj = clazz.getDeclaredConstructor().newInstance(); 175 BeanUtils.setValue(obj, value); 176 return (T) obj; 177 } catch (Exception e) { 178 return null; 179 } 180 181 } 182 } 183 184 public class JavaReflectDemo { 185 public static void main(String[] args) throws Exception{ 186 String value = "ename:Smith|job:Clerk|salary:8960.00|age:30|hiredate:2003-10-03|" 187 +"dept.dname:财务部|dept.company.name:twitter|" 188 +"dept.company.createdate:2001-11-11"; 189 Emp emp = ClassInstanceFactory.create(Emp.class, value); 190 System.out.println(emp); 191 System.out.println(emp.getDept()); 192 System.out.println(emp.getDept().getCompany()); 193 } 194 }
