在 JSON 中，对象是一个无序的、键/值对的集合，它可以与字符串或者数组进行转换，帮助开发人员提高开发速度，那json对象转换为实体类怎么操作?下面来我们就来给大家讲解一下。
Json对象转为实体对象
1、Bean中申明 trainTypeList：
public class TrainTypeQueryParam implements Serializable
{
private static final long serialVersionUID = 1 L;
private String id;
private String name;
private Integer sortIndex;
private String parentId;
private Integer corpId;
private Integer createrId; // 创建人ID
private Date createTime; // 创建时间
private Integer modifierId; // 修改人ID
private Date modifyTime; // 修改时间
private String orderBy = null;
private String sortType = "ASC";
private PageBean pageBean = new PageBean();
private ListtrainTypeList = new ArrayList();
public TrainTypeQueryParam()
{}
//getter、setter方法
}2、java代码：
/**
* @Title: updateSort
* @Description: 排序
* @param @param itemjson
* @param @param request
* @param @return
* @return MessageResp
* @throws
*/
@RequestMapping("updateSort")
@ResponseBody
public MessageResp updateSort(String itemjson, HttpServletRequest request)
{
MessageResp resp = new MessageResp();
User u = SessionUtils.getUser(request.getSession());
TrainTypeQueryParam params;
ObjectMapper mapper = new ObjectMapper();
try
{
params = mapper.readValue(itemjson, TrainTypeQueryParam.class); //Json对象转为实体对象
ListtrainTypeList = params.getTrainTypeList();
if (trainTypeList != null && trainTypeList.size() > 0)
{
for (int i = 0; i < traintypelist.size(); i++)
{
< p = "" >
TrainType trainType = new TrainType();
trainType.setId(trainTypeList.get(i)
.getId()); //ID
trainType.setSortIndex(trainTypeList.get(i)
.getSortIndex()); // trainType.setParentId(trainTypeList.get(i).getParentId());
trainTypeService.update(trainType); //排序 }
}
resp.setResult("true");
resp.setResultDesc("修改成功!");
}
catch (Exception e)
{
resp.setResult("false");
resp.setResultDesc("修改出错!");
}
return resp;
}3、jsp页面传参：
//拖拽大类
function dragBigData()
{
$(".coursecate_list")
.sortable(
{
stop: function ()
{
var i = 0;
var itemjson = {
trainTypeList: []
};
$(".coursecate_list")
.find("div")
.each(function ()
{
i++;
$(this)
.attr("data-sortIndex", i);
var arr = {
"id": $(this)
.attr("data-id")
, "sortIndex": $(this)
.attr("data-sortIndex")
}
itemjson.trainTypeList.push(arr); //此处要与Bean中申明list同名
});
var param = {
itemjson: JSON.stringify(itemjson)
};
$.ajax(
{
url: "${ctx}/td/trainType/updateSort.do "
, type: "get"
, data: param
, success: function (data) {}
});
}
})
.disableSelection();
}
//拖拽小类
function dragSmallData()
{
$(".coursesmallcate_list")
.sortable(
{
stop: function ()
{
var i = 0;
var itemjson = {
trainTypeList: []
};
$(".coursesmallcate_list")
.find("div")
.each(function ()
{
i++;
$(this)
.attr("data-sortIndex", i);
var arr = {
"id": $(this)
.attr("data-id")
, "sortIndex": $(this)
.attr("data-sortIndex")
}
itemjson.trainTypeList.push(arr); //此处要与Bean中申明list同名
});
var param = {
itemjson: JSON.stringify(itemjson)
};
$.ajax(
{
url: "${ctx}/td/trainType/updateSort.do "
, type: "get"
, data: param
, success: function (data) {}
});
}
})
.disableSelection();
}json对象与字符串如何转换?
1.简单的解析json字符串
首先将json字符串转换为json对象，然后再解析json对象，过程如下。
JSONObject jsonObject = JSONObject.fromObject(jsonStr);
根据json中的键得到它的值
String name = jsonObject.getString("name");
int num = jsonObject.getInt("num");
String sex = jsonObject.getString("sex");
int age = jsonObject.getInt("age");2.将json字符串转换为java对象
同样先将json字符串转换为json对象，再将json对象转换为java对象，如下所示。
JSONObject obj = new JSONObject().fromObject(jsonStr); //将json字符串转换为json对象
将json对象转换为java对象
Person jb = (Person)JSONObject.toBean(obj,Person.class); //将建json对象转换为Person对象
3.将java对象转换为json字符串
先将java对象转换为json对象，在将json对象转换为json字符串
JSONObject json = JSONObject.fromObject(obj); //将java对象转换为json对象 String str = json.toString();//将json对象转换为字符串
完整代码如下：
package baz.parse;
import java.util.ArrayList;
import java.util.List;
import net.sf.json.JSON;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
import net.sf.json.JSONSerializer;
import baz.bean.Person;
public class ParseJson
{
private String jsonStr;
public ParseJson()
{}
public ParseJson(String str)
{
this.jsonStr = str;
}
/**
* 解析json字符串
*/
public void parse()
{
JSONObject jsonObject = JSONObject.fromObject(jsonStr);
String name = jsonObject.getString("name");
int num = jsonObject.getInt("num");
String sex = jsonObject.getString("sex");
int age = jsonObject.getInt("age");
System.out.println(name + " " + num + " " + sex + " " + age);
}
//将json字符串转换为java对象
public Person JSON2Object()
{
//接收{}对象，此处接收数组对象会有异常
if (jsonStr.indexOf("[") != -1)
{
jsonStr = jsonStr.replace("[", "");
}
if (jsonStr.indexOf("]") != -1)
{
jsonStr = jsonStr.replace("]", "");
}
JSONObject obj = new JSONObject()
.fromObject(jsonStr); //将json字符串转换为json对象
Person jb = (Person) JSONObject.toBean(obj, Person.class); //将建json对象转换为Person对象
return jb; //返回一个Person对象
}
}package baz.bean;
public class Person
{
private String name;
private int num;
private String sex;
private int age;
public Person()
{
// TODO Auto-generated constructor stub
}
public Person(String name, int num, String sex, int age)
{
super();
this.name = name;
this.num = num;
this.sex = sex;
this.age = age;
}
public String getName()
{
return name;
}
public void setName(String name)
{
this.name = name;
}
public int getNum()
{
return num;
}
public void setNum(int num)
{
this.num = num;
}
public String getSex()
{
return sex;
}
public void setSex(String sex)
{
this.sex = sex;
}
public int getAge()
{
return age;
}
public void setAge(int age)
{
this.age = age;
}
}将java对象转换为json字符串
package baz.cons;
import net.sf.json.JSONObject;
/**
* 将java对象转换为json字符串
* @author Administrator
*
*/
public class ConsJson
{
public ConsJson()
{
// TODO Auto-generated constructor stub
}
public String Object2Json(Object obj)
{
JSONObject json = JSONObject.fromObject(obj); //将java对象转换为json对象
String str = json.toString(); //将json对象转换为字符串
return str;
}
}测试类：
package baz.test;
import java.util.List;
import baz.bean.Person;
import baz.cons.ConsJson;
import baz.parse.ParseJson;
public class Test
{
public static void main(String[] args)
{
//将字符串转换为json对象，然后根据建得到相应的值
ParseJson pj = new ParseJson("{\"name\":\"gu\",\"num\":123456,\"sex\":\"male\",\"age\":24}");
pj.parse();
//将一个json字符串转换为java对象
Person p = pj.JSON2Object();
System.out.println("Name:" + p.getName());
System.out.println("Num:" + p.getNum());
System.out.println("Sex:" + p.getSex());
System.out.println("age:" + p.getAge());
//将一个java对象转换为Json字符串
Person p1 = new Person("gu1", 123, "male", 23);
ConsJson cj = new ConsJson();
String str1 = cj.Object2Json(p1);
System.out.println(str1);
}
}测试输出如下：
gu 123456 male 24
Name:gu
Num:123456
Sex:male
age:24
1{"age":23,"name":"gu1","num":123,"sex":"male"}json对象与字符串的相互转换在工作中是最常见的，所以这是作为java开发者需要掌握的最基本的技能，另外，JSON 对象中可以嵌套其它的任意类型，例如对象、数组等哦!最后大家如果想要了解更多json工具教程知识，敬请关注奇Q工具网。
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