使用jackson工具类把对象或集合转为JSON格式

jackson使用方法：

1、加入jar包：

jackson-annotations-2.2.2.jar

jackson-core-2.2.2.jar

jackson-databind-2.2.2.jar

2、具体的使用步骤：

1）、创建org.codehaus.jackson,map.ObjectMapper 对象

2）、调用ObjectMapper 的 writeValueAsString 方法把Java 对象或集合转为JSON字符串

ObjectMapper mapper = new ObjectMapper();

String jsonStr = mapper.writerValueAsString(String str);

3、注意：

1）、Jackson 根据getter 来定位Json 对象的属性，而不是字段！

2）、可以在类的 getter 方法上添加注解：org.codehaus.jackson.annotate.JsonIgnore . 转为Json对象时已忽略该属性！

测试代码如下：

package com.lym.ajax.beans;

import java.util.Arrays;
import java.util.List;

import com.fasterxml.jackson.annotation.JsonIgnore;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;

/**
 * jackson测试类
 * @author liuyanmin
 * 2015-1-20 上午11:23:55
 */
public class ShopCart {

	private String bookName;
	private int price=0;
	private int number=0;

	public ShopCart(String bookName, int price, int number) {
		super();
		this.bookName = bookName;
		this.price = price;
		this.number = number;
	}
	public String getBookName() {
		return bookName;
	}
	public void setBookName(String bookName) {
		this.bookName = bookName;
	}
	@JsonIgnore
	public int getPrice() {
		return price;
	}
	public void setPrice(int price) {
		this.price = price;
	}
	public int getNumber() {
		return number;
	}
	public void setNumber(int number) {
		this.number = number;
	}

	public static void main(String args[]){

		ObjectMapper mapper = new ObjectMapper();

		ShopCart sc = new ShopCart("JavaEE",100,1);
		List<ShopCart> list = Arrays.asList(sc,new ShopCart("Oracle",200,2));

		try {
			String result = mapper.writeValueAsString(sc);
			String resList = mapper.writeValueAsString(list);
			System.out.println(result);
			System.out.println(resList);
		} catch (JsonProcessingException e) {
			e.printStackTrace();
		}

	}
}