java对象和json数据转换实现方式3-使用jackson实现

測试代码：

package com.yanek.util.json;

import java.io.IOException;
import java.io.StringWriter;
import java.util.ArrayList;
import java.util.List;

import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonParseException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;

public class JacksonUtil {

	/**
	 * @param args
	 */
	public static void main(String[] args) {

		Hotel h1=new Hotel();
		h1.setId(1);
		h1.setName("name1");

		Hotel h2=new Hotel();
		h2.setId(2);
		h2.setName("name2");

		RoomTypeVO t1=new RoomTypeVO();
		t1.setPrice("20");
		t1.setTypeid(1);
		t1.setTypename("nnn1");

		List<RoomTypeVO> RoomTypeVOs=new ArrayList<RoomTypeVO>();
		RoomTypeVOs.add(t1);
		RoomTypeVOs.add(t1);
		h1.setRoomTypeVOs(RoomTypeVOs);

		Hotel hotel=new Hotel();

		try {
			System.out.println("json1:::"+bean2Json(h1));

			String s=bean2Json(h1);
			hotel=json2Bean(s,Hotel.class);

			System.out.println("json2:::"+bean2Json(hotel));

			System.out.println("json3:::"+bean2Json(RoomTypeVOs));

			String s2=bean2Json(RoomTypeVOs);
			List<RoomTypeVO> RoomTypeVOs2=new ArrayList<RoomTypeVO>();
			RoomTypeVOs2=json2Bean(s2,List.class);

			System.out.println("json4:::"+bean2Json(RoomTypeVOs2));

		} catch (IOException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}

	}

	public static String bean2Json(Object obj) throws IOException {
        ObjectMapper mapper = new ObjectMapper();
        StringWriter sw = new StringWriter();
        JsonGenerator gen = new JsonFactory().createJsonGenerator(sw);
        mapper.writeValue(gen, obj);
        gen.close();
        return sw.toString();
    }

    public static <T> T json2Bean(String jsonStr, Class<T> objClass)
            throws JsonParseException, JsonMappingException, IOException {
        ObjectMapper mapper = new ObjectMapper();
        return mapper.readValue(jsonStr, objClass);
    }

}

输出例如以下：

json1:::{"id":1,"name":"name1","roomTypeVOs":[{"typeid":1,"typename":"nnn1","price":"20"},{"typeid":1,"typename":"nnn1","price":"20"}]}
json2:::{"id":1,"name":"name1","roomTypeVOs":[{"typeid":1,"typename":"nnn1","price":"20"},{"typeid":1,"typename":"nnn1","price":"20"}]}
json3:::[{"typeid":1,"typename":"nnn1","price":"20"},{"typeid":1,"typename":"nnn1","price":"20"}]
json4:::[{"typeid":1,"typename":"nnn1","price":"20"},{"typeid":1,"typename":"nnn1","price":"20"}]

相关实体类：

package com.yanek.util.json;

import java.util.List;

public class Hotel {

	public List<RoomTypeVO> getRoomTypeVOs() {
		return RoomTypeVOs;
	}
	public void setRoomTypeVOs(List<RoomTypeVO> roomTypeVOs) {
		RoomTypeVOs = roomTypeVOs;
	}
	private List<RoomTypeVO> RoomTypeVOs;

	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}

	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	private int id;
	private String name;

}

package com.yanek.util.json;

public class RoomTypeVO {

	public int getTypeid() {
		return typeid;
	}
	public void setTypeid(int typeid) {
		this.typeid = typeid;
	}

	public String getTypename() {
		return typename;
	}
	public void setTypename(String typename) {
		this.typename = typename;
	}

	public String getPrice() {
		return price;
	}
	public void setPrice(String price) {
		this.price = price;
	}
	private int typeid;
	private String typename;
	private String price;

}