代码：
ObjectUtil类：
import java.lang.reflect.Field;
import java.math.BigDecimal;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map; /**
* 利用Java反射机制对实体类的常用操作
* @author 【】
*
*/
public class ObjectUtil { SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"); SimpleDateFormat sf = new SimpleDateFormat("yyyy-MM-dd"); SimpleDateFormat sfCsv = new SimpleDateFormat("yyyyMMdd"); /**
* 根据类的名称获取类的属性信息（不包括父类）
*/
public List<Field> getFields(String className) throws ClassNotFoundException {
List<Field> list = new ArrayList<>();
Class<?> clazz = Class.forName(className);
Field[] fields = clazz.getDeclaredFields();
list.addAll(Arrays.asList(fields)); return list;
} /**
* 根据类的名称获取属性信息和父类的属性信息
*/
public List<Field> getAllFields(String className) throws ClassNotFoundException {
List<Field> list = new ArrayList<>();
Class<?> clazz = Class.forName(className);
Field[] fields = clazz.getDeclaredFields();
list.addAll(Arrays.asList(fields));
Class<?> superClazz = clazz.getSuperclass();
if (superClazz != null) {
Field[] superFields = superClazz.getDeclaredFields();
list.addAll(Arrays.asList(superFields));
}
return list;
} /**
* 根据类名和字段名获取字段在类中的类型
*/
public String getFieldClassName(String className ,String fieldName) throws ClassNotFoundException {
Class<?> clazz = Class.forName(className);
Field[] fields = clazz.getDeclaredFields();
for (Field field : fields) {
if (field.getName().equals(fieldName)) {
return field.getType().getSimpleName();
}
}
return "";
} /**
* 获取传入对象的指定属性的值
*/
public String getValueByPropName(Object obj, String propName) {
String value = null;
try {
// 获取对象的属性
Field field = obj.getClass().getDeclaredField(propName);
// 对象的属性的访问权限设置为可访问
field.setAccessible(true);
value = field.get(obj).toString();
} catch (Exception e) {
return null;
} return value;
} /**
* 根据传入对象获取其属性、类型、属性值的集合
*/
public List<Map<String, Object>> getFiledsInfo(Object o) {
Field[] fields = o.getClass().getDeclaredFields();
List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();
Map<String, Object> infoMap = null;
for (int i = 0; i < fields.length; i++) {
infoMap = new HashMap<String, Object>();
infoMap.put("type", fields[i].getType().toString());
infoMap.put("name", fields[i].getName());
infoMap.put("value", getValueByPropName(o, fields[i].getName()));
list.add(infoMap);
}
return list;
} /**
* 根据类的名称获取该类和该注解值的map集合(包括父类)
* （注：注解Comment是为代码完整自定义的注解，可根据实际需求要获取的注解直接替换即可）
*/
public Map<String, String> getAnnotationVal(String className) {
Map<String, String> map = new HashMap<>();
try {
List<Field> lists = getAllFields(className);
for (Field field : lists) {
// 设置访问对象权限，保证对私有属性的访问
field.setAccessible(true);
// 判断该字段是否存在@Comment注解
if (!field.isAnnotationPresent(Comment.class)) {
continue;
}
// 获取字段中对应的注解@Comment对象
Comment comment = field.getAnnotation(Comment.class);
// 获取自定义注解的值
String value = comment.value();
if (value != null && !"".equals(value)) {
map.put(field.getName(), value);
}
}
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
return map;
} /**
* 判断该类是否存在该属性（不包括父类）
*/
public boolean existsField(String className, String fieldName) throws ClassNotFoundException {
boolean flag = false;
Class<?> clazz = Class.forName(className);
Field[] fields = clazz.getDeclaredFields();
for (Field field : fields) {
if (field.getName().equals(fieldName)) {
flag = true;
break;
}
}
return flag;
} /**
* 给该类的该字段设值
*/
public void setFieldValue(String fieldName, String fieldValue, Object object) {
Field field = null;
try {
boolean isExist = false;
Field[] fields = object.getClass().getDeclaredFields();
for (Field var : fields) {
if (var.getName().equals(fieldName)) {
isExist = true;
field = object.getClass().getDeclaredField(fieldName);
break;
}
} if (!isExist) {
field = object.getClass().getSuperclass().getDeclaredField(fieldName);
}
// 设置对象的访问权限，保证对private的属性的访问
field.setAccessible(true); if ("class java.math.BigDecimal".equals(field.getType().toString())) {
field.set(object, new BigDecimal(fieldValue.trim()));
} else if ("Date".equals(field.getType().getSimpleName())) {
if (fieldValue.toString().indexOf("/") > 0) {
fieldValue = fieldValue.toString().replace('/', '-');
}
if (fieldValue.toString().length() == 8) {
Date date = sfCsv.parse(fieldValue.toString());
field.set(object, date);
} else if (fieldValue.toString().length() == 10) {
Date date = sf.parse(fieldValue.toString());
field.set(object, date);
} else {
Date date = sdf.parse(fieldValue.toString());
field.set(object, date);
}
// field.set(object, sdf.parse(fieldValue));
} else if ("class java.lang.Integer".equals(field.getType().toString())) {
field.set(object, Integer.valueOf(fieldValue));
} else {
field.set(object, fieldValue);
}
} catch (Exception e) { }
} public static void main(String[] args) throws Exception {
ObjectUtil util = new ObjectUtil(); /*List<Field> fields = util.getFields(Student.class.getName());
for (Field field : fields) {
// 设置访问对象权限，保证对私有属性的访问
field.setAccessible(true);
System.out.println(field.getName());
}*/ /*List<Field> fields = util.getAllFields(Student.class.getName());
for (Field field : fields) {
// 设置访问对象权限，保证对私有属性的访问
field.setAccessible(true);
System.out.println(field.getName());
}*/ /*String str = util.getFieldClassName(Student.class.getName(), "name");
System.out.println(str);*/ /*Student stu = new Student();
stu.setName("Jack");
stu.setSex("男");
String value = util.getValueByPropName(stu, "name");
System.out.println(value);*/ /*Student stu = new Student();
stu.setName("Jack");
stu.setSex("男");
List<Map<String, Object>> lists = util.getFiledsInfo(stu);
for (Map<String, Object> map : lists) {
System.out.println(map.get("name"));
System.out.println(map.get("type"));
System.out.println(map.get("value"));
}*/ /*Map<String, String> map = util.getAnnotationVal(Student.class.getName());
for (String key : map.keySet()) {
System.out.println(map.get(key) + "——————" + key);
}*/ /*boolean flag = util.existsField(Student.class.getName(), "name");
System.out.println(flag);*/ Student stu = new Student();
util.setFieldValue("name", "Rose", stu);
System.out.println(stu.getName());
}
}
测试实体类Student:
public class Student {
@Comment(value = "姓名")
private String name;
@Comment(value = "性别")
private String sex;
@Comment(value = "年龄")
private String age;
@Comment(value = "班级")
private String stuClass;
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getSex() {
return sex;
}
public void setSex(String sex) {
this.sex = sex;
}
public String getAge() {
return age;
}
public void setAge(String age) {
this.age = age;
}
public String getStuClass() {
return stuClass;
}
public void setStuClass(String stuClass) {
this.stuClass = stuClass;
}
}
测试自定义注解@Comment：
import static java.lang.annotation.RetentionPolicy.RUNTIME; import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;
/**
* 自定义属性注解
* @author 【】
*
*/
@Target({ ElementType.FIELD, ElementType.TYPE })
@Retention(RUNTIME)
public @interface Comment {
// 定义注解中的属性，默认值为空字符串
String value() default "";
}