Servlet Post中使用org.json处理Json和上位机中使用Newtonsoft.Json

1.获取Post传送的数据

这里我们借助Apache Commons IO中的IOUtils类

<dependency>
    <groupId>commons-io</groupId>
    <artifactId>commons-io</artifactId>
    <version>2.6</version>
</dependency>

将Post的数据流转成String

如果不用commons io类库，自己转换的方法

public static String receivePost(HttpServletRequest request) throws IOException, UnsupportedEncodingException {
        
        // 读取请求内容
        BufferedReader br = new BufferedReader(new InputStreamReader(request.getInputStream()));
        String line = null;
        StringBuilder sb = new StringBuilder();
        while((line = br.readLine())!=null){
            sb.append(line);
        }

        // 将资料解码
        String reqBody = sb.toString();
        return URLDecoder.decode(reqBody, HTTP.UTF_8);
    }

 或者

InputStream sin = new BufferedInputStream(request.getInputStream());
ByteArrayOutputStream sout = new ByteArrayOutputStream();
int b=0;
while((b=sin.read())!=-1)
{
sout.write(b);
}
byte[] temp = sout.toByteArray();
String s_ok = new String(temp,"UTF-8");

2.

 使用org.json和Newtonsoft.Json

Json 对象的生成和操作

newtonsoft.json

JObject j = new JObject();
j["id"] = 32;
j.Add("name", "John");
Console.WriteLine(j.ToString());
Console.WriteLine("ID和姓名分别是:" + (int)j["id"] + "  " + j["name"]);

org.json

JSONObject j=new JSONObject();
j.put("id", 32);
j.put("name", "John");
System.out.println(j.toString());
System.out.println("ID和姓名分别是:"+j.getInt("id")+"  "+j.getString("name"));

注意newtonsoft添加和获取键值对使用 ["key"],上面都输出

{"name":"John","id":32}
ID和姓名分别是:32 John

 由字符串生成json对象

newtonsoft.json

string str = "{"id":7,"status":"good","gender":"male","addr":"mit"}";
//下面两行等效
JObject J = JObject.Parse(str);
JObject j = JsonConvert.DeserializeObject(str) as JObject;
j["status"] = "baaaaaad";
Console.WriteLine(j.ToString());
String str2 = "[{ID:'1',Name:'John'},{ID:'2',Name:'Alan'}]";
JArray ar = JsonConvert.DeserializeObject(str2) as JArray;
//遍历Array对象
for (int i = 0; i < ar.Count; i++)
{
    JObject tmp = ar[i] as JObject;
    Console.WriteLine(tmp);
}

org.json

String str="{"id":7,"status":"good","gender":"male","addr":"mit"}";
JSONObject j=new JSONObject(str);
j.put("status", "baaaaaad");
System.out.println(j.toString());
String str2="[{ID:'1',Name:'John'},{ID:'2',Name:'Alan'}]";
JSONArray ar=new JSONArray(str2);
//遍历Array对象
for(int i=0;i<ar.length();i++) {
    JSONObject tmp=ar.getJSONObject(i);
    System.out.println(tmp);
}

 上面 都输出

{"gender":"male","id":7,"addr":"mit","status":"baaaaaad"}
{"ID":"1","Name":"John"}
{"ID":"2","Name":"Alan"}

由普通对象和数据结构生成json对象

关于Person类

//在C#中
class Person
{
    public int id { set; get; }
    public string name { set; get; }
    public string place { set; get; }
}

//在Java中
public class Person {
	Integer id;
    String name;
    String place;
    public Person() {
    	
    }
....
//getter and setter

　　

newtonsoft.json

Person p = new Person();
p.id = 32;
p.name = "Jack";
p.place = "New York";
JObject j = JObject.FromObject(p);
Console.WriteLine(j);

Dictionary<string, object> d = new Dictionary<string, object>();
d.Add("name", "Alan");
d.Add("age", 44);
d.Add("title", "Worker");
JObject j1 = JObject.FromObject(d);
Console.WriteLine(j1);

org.json

Person p=new Person();
p.setId(32);
p.setName("Jack");
p.setPlace("New York");
JSONObject j=new JSONObject(p);
System.out.println(j.toString());

Map<String,Object> m=new HashMap<String,Object>();
m.put("name", "Alan");
m.put("age", 44);
m.put("title", "worker");
JSONObject j1=new JSONObject(m);
System.out.println(j1.toString());

以上都输出

{"name":"Jack","id":32,"place":"New York"}
{"name":"Alan","title":"worker","age":44}

newtonsoft的json字符串和普通对象的直接转换

对象到字符串

String str=JsonConvert.SerializeObject(p);

字符串到对象

Person p1= JsonConvert.DeserializeObject<Person>(str);

或者

Person p2 = JsonConvert.DeserializeObject(str, typeof(Person)) as Person;

3相关库的获取

获取Newtonsoft.Json包

到https://www.nuget.org/downloads 下载VS2013的插件，安装好之后。

打开你的工程，然后选择菜单中的工具

点击控制台，输入

PM> Install-Package Newtonsoft.Json

这样Newtonsoft.Json 就被添加到引用中了。

获取org.json

<dependency>
<groupId>org.json</groupId>
<artifactId>json</artifactId>
<version>20180130</version>
</dependency>