json to bean 和 bean to json

第一步：导入gson的jar包：gson-2.2.2.jar

第二部：编写Java代码：

  1.java bean：

public class MessageBean {
private String id;
private String name;
private String age;
private List list=new ArrayList();

...........................................省略

}

2.编写工具类：

public class JsonUtil {
public static void main(String[] args) {
String json=toJsonString();
getBean(json);
}
public static String toJsonString(){
List mbList=new ArrayList();
for(int k=0;k<10;k++){
MessageBean mb=new MessageBean();
List list=new ArrayList();
list.add("小米");
list.add("西瓜");
mb.setAge("23");
mb.setId(k+"");
mb.setName("ljf");
mb.setList(list);
mbList.add(mb);
}


Gson gson = new Gson();
String s=gson.toJson(mbList);
System.out.println(s);
return s;

}
public static void getBean(String json){
Gson gson = new Gson();//http://blog.csdn.net/u011240877/article/details/52625942
List mbList=gson.fromJson(json,new TypeToken>() {}.getType());
for(MessageBean mb:mbList){
System.out.println(mb.getName()+">>"+mb.getId());
List list=mb.getList();
for(String ss:list){
System.out.println(ss);
}
}

}
}

结果为：

[{"id":"0","name":"ljf","age":"23","list":["小米","西瓜"]},{"id":"1","name":"ljf","age":"23","list":["小米","西瓜"]},{"id":"2","name":"ljf","age":"23","list":["小米","西瓜"]},{"id":"3","name":"ljf","age":"23","list":["小米","西瓜"]},{"id":"4","name":"ljf","age":"23","list":["小米","西瓜"]},{"id":"5","name":"ljf","age":"23","list":["小米","西瓜"]},{"id":"6","name":"ljf","age":"23","list":["小米","西瓜"]},{"id":"7","name":"ljf","age":"23","list":["小米","西瓜"]},{"id":"8","name":"ljf","age":"23","list":["小米","西瓜"]},{"id":"9","name":"ljf","age":"23","list":["小米","西瓜"]}]
ljf>>0
小米
西瓜
ljf>>1
小米
西瓜
ljf>>2

。。。。。。。省略部分

三 gson将son转javabean，对字段不一致，做映射机制，不报错，忽略不一致的字段；

kafkabondsData：此javabean的属性字段：

private String id;//编号id

private String title;//标题
private String content;//内容
private String url;//采集路径

执行代码：

String json="{\"url\":\"http:dd\",\"name\":\"ljf\"}";
 Gson gson=new Gson();
   KafkaBondsData kbd= gson.fromJson(json, KafkaBondsData.class);
 System.out.println(kbd.getUrl());

结果：

http:dd

3.gson的maven坐标依赖

   com.google.code.gson
   gson
   2.2.4

详情代码见百度网盘 java/