05.24 使用java反射簡單模擬json數據

在做項目時，公司催進度，往往是接口都還沒有寫好，產品就開始要各種演示版本，為了演示的時候能展示數據，往往就需要客戶端自己模擬數據，以達到展示的目的，這是苦逼，我就上網百度了一下，再發揮自己的聰明才智，寫了一個模擬json數據的轉化工具類，方便大家自舉。

public class JsonUtil {

 public static String class2json(Object obj) {
 // 通過反射獲取到類
 Class extends Object> clazz = obj.getClass();
 // 獲取類中所有的字段
 Field[] fields = clazz.getDeclaredFields();

 StringBuffer buffer = new StringBuffer();
 buffer.append("{");
 // 設置setAccessible方法能獲取到類中的私有屬性和方法
 Field.setAccessible(fields, true);
 for (Field field : fields) {

 try {

 Object object = field.get(obj);

 // 獲取到該屬性對應類型名稱
 String fieldName = field.getType().getSimpleName();

 // 如果該屬性的值為空
 if (object == null) {

 // 根據類型判斷追加的值
 if (fieldName.equals("String")) {
 buffer.append("\\"" + field.getName() + "\\":\\"\\",");
 } else if (fieldName.equals("Boolean")
 || fieldName.equals("Integer")
 || fieldName.equals("Double")
 || fieldName.equals("Float")
 || fieldName.equals("Long")) {

 buffer.append("\\"" + field.getName() + "\\":0,");
 }

 else {
 buffer.append("\\"" + field.getName() + "\\":null,");
 }

 } else {

 // 獲取到該屬性的值對應的類 

 Class extends Object> fieldclass = object.getClass();
 String simpleName = fieldclass.getSimpleName();

 if (simpleName.equals("String")) {

 buffer.append("\\"" + field.getName() + "\\":\\""
 + field.get(obj) + "\\",");

 } else if (simpleName.equals("Boolean")
 || simpleName.equals("Integer")
 || simpleName.equals("Double")
 || simpleName.equals("Float")
 || simpleName.equals("Long")) {

 buffer.append("\\"" + field.getName() + "\\":"
 + field.get(obj) + ",");

 } else if (simpleName.equals("Date")) {

 Date date = (Date) object;
 SimpleDateFormat simpleDateFormat = new SimpleDateFormat(
 "yyyy-MM-dd hh:mm:ss");
 String simdate = simpleDateFormat.format(date);
 buffer.append("\\"" + field.getName() + "\\":\\""
 + simdate + "\\",");

 } else if (simpleName.equals("ArrayList")
 || simpleName.equals("LinkedList")) {
 // 將獲取到的值強轉為list集合
 List<object> list = (List<object>) object;
 buffer.append("\\"" + field.getName() + "\\":[");

 // 執行listTojson方法將獲取到的list轉為json格式
 buffer = listTojson(buffer, list).append("]");
 } else {

 buffer = beanTojson(object, buffer).append(",");
 }
 }

 } catch (Exception e) {
 // TODO Auto-generated catch block
 e.printStackTrace();
 }

 }
 buffer = new StringBuffer(buffer.substring(0, buffer.length() - 1));
 buffer.append("}"); 


 return buffer.toString();
 }

 public static StringBuffer listTojson(StringBuffer buffer, List list)
 throws IllegalArgumentException, IllegalAccessException {

 // 遍歷傳過來的list數組
 for (Object object : list) {

 // 判斷遍歷出的值是否為空
 if (object == null) {
 buffer.append(",");
 } else {

 Class extends Object> class1 = object.getClass();
 String simpleName = class1.getSimpleName();

 if (simpleName.equals("String")) {

 buffer.append("\\"" + object.toString() + "\\",");
 } else if (simpleName.equals("Boolean")
 || simpleName.equals("Integer")
 || simpleName.equals("Double")
 || simpleName.equals("Float")
 || simpleName.equals("Long")) {

 buffer.append("" + object.toString() + ",");
 } else if (simpleName.equals("Date")) {
 Date date = (Date) object;
 SimpleDateFormat simpleDateFormat = new SimpleDateFormat(
 "yyyy-MM-dd hh:mm:ss");
 String simdate = simpleDateFormat.format(date);
 buffer.append("" + simdate + ",");
 } else {

 Class extends Object> class2 = object.getClass();
 Field[] fields = class2.getDeclaredFields();
 Field.setAccessible(fields, true);
 buffer.append("{");
 // 遍歷對象中的所有字段獲取字段值和字段名稱拼成json字符串
 for (Field field : fields) {

 Object fieldobj = field.get(object);
 String fieldName = field.getType().getSimpleName();
 

 if (fieldobj == null) {

 if (fieldName.equals("String")) {
 buffer.append("\\"" + field.getName()
 + "\\":\\"\\",");
 }

 else {
 buffer.append("\\"" + field.getName()
 + "\\":null,");
 }

 }

 else {

 String fsimpleName = fieldobj.getClass()
 .getSimpleName();

 if (fsimpleName.equals("String")) {

 buffer.append("\\"" + field.getName() + "\\":\\""
 + field.get(object) + "\\",");
 } else if (fsimpleName.equals("Boolean")
 || fsimpleName.equals("Integer")
 || fsimpleName.equals("Double")
 || fsimpleName.equals("Float")
 || fsimpleName.equals("Long")) {

 buffer.append("\\"" + field.getName() + "\\":"
 + field.get(object) + ",");
 } else if (fsimpleName.equals("Date")) {

 Date date = (Date) object;
 SimpleDateFormat simpleDateFormat = new SimpleDateFormat(
 "yyyy-MM-dd hh:mm:ss");
 String simdate = simpleDateFormat.format(date);
 buffer.append("\\"" + field.getName() + "\\":"
 + simdate + ",");
 } else {

 buffer = beanTojson(fieldobj, buffer).append(
 ",");
 }
 }

 }

 buffer = new StringBuffer(""
 + buffer.substring(0, buffer.length() - 1) + ""); 

 buffer.append("},");
 }
 }

 }

 buffer = new StringBuffer("" + buffer.substring(0, buffer.length() - 1)
 + "");
 buffer.append("]");

 return buffer;
 }

 public static StringBuffer beanTojson(Object obj, StringBuffer buffer)
 throws IllegalArgumentException, IllegalAccessException {

 Class extends Object> clazz = obj.getClass();
 Field[] declaredFields = clazz.getDeclaredFields();
 Field.setAccessible(declaredFields, true);

 buffer.append("\\"" + clazz.getSimpleName() + "\\":{");

 for (Field field : declaredFields) {

 Object object = field.get(obj);
 String fieldName = field.getType().getSimpleName();

 if (object == null) {
 if (fieldName.equals("String")) {
 buffer.append("\\"" + field.getName() + "\\":\\"\\",");
 }

 else {
 buffer.append("\\"" + field.getName() + "\\":null,");
 }

 } else {

 Class extends Object> fieldclass = object.getClass();
 String simpleName = fieldclass.getSimpleName();

 if (simpleName.equals("String")) {

 buffer.append("\\"" + field.getName() + "\\":\\""
 + field.get(obj) + "\\",");
 } else if (simpleName.equals("Boolean")
 || simpleName.equals("Integer")
 || simpleName.equals("Double")
 || simpleName.equals("Float")
 || simpleName.equals("Long")) { 


 buffer.append("\\"" + field.getName() + "\\":"
 + field.get(obj) + ",");
 } else if (simpleName.equals("Date")) {

 Date date = (Date) object;
 SimpleDateFormat simpleDateFormat = new SimpleDateFormat(
 "yyyy-MM-dd hh:mm:ss");
 String simdate = simpleDateFormat.format(date);
 buffer.append("\\"" + field.getName() + "\\":\\"" + simdate
 + "\\",");
 } else if (simpleName.equals("ArrayList")
 || simpleName.equals("LinkedList")) {

 List<object> list = (List<object>) object;
 buffer = listTojson(buffer, list);
 } else {
 buffer = beanTojson(object, buffer).append("}");
 }
 }

 }

 buffer = new StringBuffer("" + buffer.substring(0, buffer.length() - 1)
 + "");
 buffer.append("}");

 return buffer;
 }

}
/<object>/<object>/<object>/<object>

使用方法

1.先定義好自己的返回樣式

public class Result {
 int code;
 String message;
 List pigArray;
 public int getCode() {
 return code;
 } 

 public void setCode(int code) {
 this.code = code;
 }
 public String getMessage() {
 return message;
 }
 public void setMessage(String message) {
 this.message = message;
 }
 public List getPigArray() {
 return pigArray;
 }
 public void setPigArray(List pigArray) {
 this.pigArray = pigArray;
 }

 

}
public class Pig {
 int age;
 int weight;
public int getAge() {
 return age;
}
public void setAge(int age) {
 this.age = age;
}
public int getWeight() {
 return weight;
}
public void setWeight(int weight) {
 this.weight = weight;
}
 
}

最後在程序中調用

Result rs=new Result();
 rs.setCode(1);
 rs.setMessage("用戶有數據"); 

 List list=new ArrayList();
 Pig p= new Pig();
 p.setAge(10);
 p.setWeight(23);
 list.add(p);
 rs.setPigArray(list);
 System.out.println("json:" +JsonUtil.class2json(rs));

效果如下：

{
 "code": 1,
 "message": "用戶有數據",
 "pigArray": [{
 "age": 10,
 "weight": 23
 }]
}