FastJson数据解析

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Fastjson 是一个性能很好的 Java 语言实现的 JSON 解析器和生成器,来自阿里巴巴的工程师开发。

主要特点:
  • 快速FAST (比其它任何基于Java的解析器和生成器更快,包括jackson)
  • 强大(支持普通JDK类包括任意Java Bean Class、Collection、Map、Date或enum)
  • 零依赖(没有依赖其它任何类库除了JDK)

1.下载地址https://github.com/alibaba/fastjson/archive/1.2.4.zip


2.FastJson主要类

JSON 主要类,一般使用静态方法,序列化java bean序列化为json文本或者json字符串反序列化为相应对象
JSONObject Json对象
JSONReader JsonReader,可以在本地读取或者网络读取数据并可以反序列化
JSONWriter JsonWriter,可以将对象序列化Json字符串,写入本地或者发送至服务
TypeReference #类型引用在反序列化化很常用

3.Fastjson API入口类是com.alibaba.fastjson.JSON,常用的序列化操作都可以在JSON类上的静态方法直接完成。

<span style="font-size:12px;">public static final Object parse(String text); // 把JSON文本parse为JSONObject或者JSONArray 
public static final JSONObject parSEObject(String text); // 把JSON文本parse成JSONObject    
public static final  T parSEObject(String text,Class clazz); // 把JSON文本parse为JavaBean 
public static final JSONArray parseArray(String text); // 把JSON文本parse成JSONArray 
public static final  List parseArray(String text,Class clazz); //把JSON文本parse成JavaBean集合 
public static final String toJSONString(Object object); // 将JavaBean序列化为JSON文本 
public static final String toJSONString(Object object,boolean prettyFormat); // 将JavaBean序列化为带格式的JSON文本 
public static final Object toJSON(Object javaObject); 将JavaBean转换为JSONObject或者JSONArray。</span>

4.效果

{CSDN:CODE:
public class JsonTest {


 public static void main(String[] args) throws IOException,Exception {


  /*
  * 1.将指定的 JavaBean对象解析成Json字符串
  */
  Person p1 = new Person("zhangsan",22,1332117);
// 字段的get属性
  System.out.println(JSON.toJSONString(p1));


  /*
  * 2.将封装了javaBean对象的集合解析成json字符串,并对该数据进行过滤
  */
  ValueFilter valueFilter = new ValueFilter() {
  @Override
  public Object process(Object source,String name,Object value) {
   if (value.equals("lisi")) {
   return " 159785";
  }
  return value;
  }
  };
  List list = new ArrayList();
  list.add(new Person("lisi",19,159785));
  list.add(new Person("wangwu",10,113123213));
  list.add(new Person("zhaoliu",29,1444785));
  System.out.println(JSON.toJSONString(list,valueFilter));


  /*
  * 3.将List>集合 转换为json字符串
  */
  List> list2 = new ArrayList>();
  Map map1 = new HashMap();
  map1.put("001",new Person("wangwu",159785));
  map1.put("002",new Person("lisi",159785));
  map1.put("003",159785));
  Map map2 = new HashMap();
  map2.put("001",new Person("zhaoliu",159785));
  map2.put("002",159785));
  map2.put("003",159785));
  list2.add(map1);
  list2.add(map2);
  System.out.println(JSON.toJSONString(list2));


  /*
  * 4.将指定的字符串解析成 指定的javaBean对象(使用泛型)
  */
// 字段的set属性
  Person p2 = JSON.parSEObject(Person.getUtil(1),Person.class);


  /*
  * 5.将指定的字符串解析成 封装了指定javaBean对象的集合
  */
  // 方法一:
  List list1 = JSON.parseArray(Person.getUtil(2),Person.class);
  // 方法二:
  List list4 = JSON.parSEObject(Person.getUtil(2),new TypeReference>(){});


  /*
  * 6.将json字符串 解析成 List>集合 ,注意Type类型的定义
  */
  // 关键type类型
  List> list3 = JSON.parSEObject(Person.getUtil(3),new TypeReference>>(){});


  /*
  * 7.将json字符串解析为 JsonObject对象, 由于该对象继承了map,可以得到键值对
  */
  JSONObject object = (JSONObject) JSON.parse(Person.getUtil(1));
  System.out.println("name:" + object.getString("name"));
  System.out.println("age:" + object.getIntValue("age"));
  System.out.println("number:" + object.getIntValue("number"));


  /*
  * 8.name过滤器,只能对name进行更新,不管是否显示
  */
  NameFilter filter = new NameFilter() {
  @Override
  public String process(Object source,Object value) {
  // source是当前对象, name是key, value实在值
  if ("age".equals(name)) {
   return "AGE";
   }
   return name;
  // {"age":22,"name":"zhangsan","number":1332117} //过滤前
  // {"AGE":22,"number":1332117} //过滤后
   }
  };
  JSONSerializer jsonSerializer = new JSONSerializer();
// 通过增加一个过滤器,为name和值进行过滤
  jsonSerializer.getNameFilters().add(filter);
  jsonSerializer.write(p1);
  System.out.println(jsonSerializer.toString());


  /*
  * 9.属性过滤器PropertyFilter,满足要求的可以不做显示
  */
  PropertyFilter propertyFilter = new PropertyFilter() {
  @Override
  public boolean apply(Object source,Object value) {
  if ("age".equals(name)) {
   return true;
  }
   return false;
  }
  };
  JSONSerializer jsonSerializer2 = new JSONSerializer();
  jsonSerializer2.getPropertyFilters().add(propertyFilter);
  jsonSerializer2.write(list);
  System.out.println(jsonSerializer2.toString());


  /*
  * 10.值过滤器ValueFilter,对满足要求的可以不做显示
  */
  ValueFilter valueFilter2 = new ValueFilter() {
  @Override
  public Object process(Object source,Object value) {
  if (value.equals(10)) {
   return null;
  }
   return value;
  }
  };
  JSONSerializer jsonSerializer3 = new JSONSerializer();
  jsonSerializer3.getValueFilters().add(valueFilter2);
  jsonSerializer3.write(list);
  System.out.println(jsonSerializer3.toString());


  /*
  * 11.在本地路径下读取文件的json字符串信息,得到数据并赋值javaBean对象
  */
  JSONReader reader = new JSONReader(new FileReader("C:\\Test.txt"));
  // 注意type的使用
  List list10 = reader.readObject(new TypeReference>() {}.getType());
  reader.close();


  /*
  * 12.将Object对象保存至本地路径中,保存为json字符串
  */
  JSONWriter writer = new JSONWriter(new FileWriter("c:\\Test.txt"));
  writer.writeObject(list10);
  writer.close();


  /*
  * 13.在网络上获取json数据,并保存为对应的javaBean对象信息
  */
  List list11 = null;
  URL url = new URL("http://192.168.117.114:8080/Test/My");
  HttpURLConnection conn = (HttpURLConnection) url.openConnection();
  conn.setRequestMethod("GET");
  conn.setConnectTimeout(3000);
  if (conn.getResponseCode() == 200) {
  InputStream in = conn.getInputStream();
  // 通过JsonReader类得到发出的输出流对象
  JSONReader reader2 = new JSONReader(new InputStreamReader(in));
  // 得到Object对象
  list11 = reader2.readObject(new TypeReference>(){}.getType());
  }
  for (Person p : list11) {
   System.out.println(p);
  }


  /*
  * 14.将客户端的javaBean对象,上传至服务器
  */
  byte[] bytes = JSON.toJSONBytes(list11);
  URL url2 = new URL("http://192.168.117.114:8080/Test/My");
  HttpURLConnection conn2 = (HttpURLConnection) url2.openConnection();
  conn2.setRequestMethod("POST");
  conn2.setConnectTimeout(3000);
  conn2.setRequestProperty("content-length",String.valueOf(bytes.length));
  conn2.setRequestProperty("content-type","application/x-www-form-urlencoded");
  conn2.setDoOutput(true);
  OutputStream os = conn2.getOutputStream();
  os.write(bytes,bytes.length);
  os.close();
  if (conn2.getResponseCode() == 200) {
   System.out.println("上传成功! ");
  }
}
}


{CSDN:CODE:

public class class Person {
public static String getUtil(int type) {
switch (type) {
case 1:
return new String(
  "{\"age\":22,\"name\":\"zhangsan\",\"number\":1332117}");
break;


  case 2:
  return new String(
  "[{\"age\":19,\"name\":\"lisi\",\"number\":159785},"
  + "{\"age\":10,\"name\":\"wangwu\",\"number\":113123213},"
  + "{\"age\":29,\"name\":\"zhaoliu\",\"number\":1444785}]");
break;


  case 3:
  return new String(
  "[{\"001\":{\"age\":19,"
  + "\"002\":{\"age\":19,"
  + "\"003\":{\"age\":19,\"number\":159785}},"
  + "{\"001\":{\"age\":23,\"number\":159785}}]");
break;


default :
   return null;
break;
}


private String name;


private int age;


private int number;


public Person() {
 super();
}


public Person(String name,int age,int number) {
 super();
 this.name = name;
 this.age = age;
 this.number = number;
}


public String getName() {
 return name;
}


public void setName(String name) {
 this.name = name;
}


public int getAge() {
 return age;
}


public void setAge(int age) {
 this.age = age;
}


public int getNumber() {
 return number;
}


public void setNumber(int number) {
 this.number = number;
}


@Override
public String toString() {
 return "Person [age=" + age + ",name=" + name + ",number=" + number + "]";
}
 }
}

}

原文链接:https://www.f2er.com/json/289786.html

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