java怎么读取json格式的数据

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java怎么读取json格式的数据,第1张

java可以使用JSONObject和JSONArray来操作json对象和json数组，具体用法如下

1:java对象与json串转换：

java对象—json串：

JSONObject JSONStr = JSONObject.fromObject(object)

String str = JSONStr.toString()

json串—java对象：

JSONObject jsonObject = JSONObject.fromObject( jsonString )

Object pojo = JSONObject.toBean(jsonObject,pojoCalss)

2:java数组对象与json串转换：

java数组—json串：

JSONArray arrayStr = JSONArray.fromObject(List<?>)

String str = arrayStr.toString()

json串—java数组：

JSONArray array = JSONArray.fromObject(str)

List<?>list = JSONArray.toList(array, ?.class)

如果不是Android开发环境的话，首先需要引入处理JSON数据的包：json-lib-2.2.3-jdk15.jar

Java样例程序如下：

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import net.sf.json.JSONArray

import net.sf.json.JSONObject

public class DoJSON {

public static void main(String[] args) {

JSONArray employees = new JSONArray() //JSON数组

JSONObject employee = new JSONObject()//JSON对象

employee.put("firstName", "Bill")//按“键-值”对形式存储数据到JSON对象中

employee.put("lastName", "Gates")

employees.add(employee) //将JSON对象加入到JSON数组中

employee.put("firstName", "George")

employee.put("lastName", "Bush")

employees.add(employee)

employee.put("firstName", "Thomas")

employee.put("lastName", "Carter")

employees.add(employee)

System.out.println(employees.toString())

for(int i=0i<employees.size()i++) {

JSONObject emp = employees.getJSONObject(i)

System.out.println(emp.toString())

System.out.println("FirstName :\t" + emp.get("firstName"))

System.out.println("LastName : \t" + emp.get("lastName"))

}

}

}

运行效果：

[{"firstName":"Bill","lastName":"Gates"},{"firstName":"George","lastName":"Bush"},{"firstName":"Thomas","lastName":"Carter"}]

{"firstName":"Bill","lastName":"Gates"}

FirstName : Bill

LastName : Gates

{"firstName":"George","lastName":"Bush"}

FirstName : George

LastName : Bush

{"firstName":"Thomas","lastName":"Carter"}

FirstName : Thomas

LastName : Carter