FastJson解析JSON的核心就是把json資料直接轉換成物件，讓解析複雜的json資料變得非常簡單，較大的降低了出錯的可能性。

使用方法：

1.建立JSON資料物件，所有的json鍵值都使用key作為變數名，並且實現set,get函式。

下面試簡單的demo測試複雜的json資料。

工程程式碼

工程結構：

files/json.txt:

{"face":[{"position":{"mouth_right":{"y":21.687167,"x":57.765155},"mouth_left":{"y":20.749833,"x":52.425537},"center":{"y":18.583333,"x":56.205251},"height":10.166667,"width":14.558473,"nose":{"y":18.785333,"x":56.317422},"eye_left":{"y":14.81305,"x":52.951074},"eye_right":{"y":16.054433,"x":60.904535}},"attribute":{"race":{"value":"Asian","confidence":90.348},"gender":{"value":"Female","confidence":99.9999},"smiling":{"value":0.490444},"age":{"value":11,"range":5}},"tag":"","face_id":"403f40726858a195ea3aec08c4f05354"}],"session_id":"6cdc4eac5f86433f9ce041993df1555e","img_height":1001,"img_width":700,"img_id":"dc6e6d69d669e4bf20a111f58361fb3e","url":"http:\/\/d.hiphotos.baidu.com\/image\/w%3D2048\/sign=618830d52c738bd4c421b53195b386d6\/3c6d55fbb2fb4316d61e357222a4462309f7d3b1.jpg","response_code":200}
 

程式碼Demo.java：

package com.jyc;

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

import com.alibaba.fastjson.JSON;


public class Demo {

	
	public Demo(){
		String json = readFile("files/json.txt");
		System.out.println(json);
		FacesResult result = JSON.parseObject(json, FacesResult.class);
		System.out.println(JSON.toJSONString(result));
	}
	
	public String readFile(String file){
		try {
			FileInputStream fis = new FileInputStream(file);
			StringBuffer sb = new StringBuffer();
			int len = 0;
			while(true){
				byte[] b = new byte[1024];
				len = fis.read(b);
				if(len<0){
					break;
				}
				sb.append(new String(b,0, len));
			}
			return sb.toString();
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
		return null;
	}
	
	/**
	 * @param args
	 */
	public static void main(String[] args) {
		new Demo();
	}


}
 

package com.jyc;

import java.util.ArrayList;
import java.util.List;

/**
 * @author jiangyuchen
 * @date 2014-3-6
 */
public class FacesResult {
	private static final String TAG = "JavaTest.Face";
	//List對應陣列
	List<Face> face = new ArrayList<Face>();
	String session_id;
	int img_height;
	int img_width;
	String img_id;
	String url;
	String response_code;
	/*
	 *所有的成員變數都要實現set get
	 */
	
	
	public List<Face> getFace() {
		return face;
	}
	public void setFace(List<Face> face) {
		this.face = face;
	}
	public String getSession_id() {
		return session_id;
	}
	public void setSession_id(String session_id) {
		this.session_id = session_id;
	}
	public int getImg_height() {
		return img_height;
	}
	public void setImg_height(int img_height) {
		this.img_height = img_height;
	}
	public int getImg_width() {
		return img_width;
	}
	public void setImg_width(int img_width) {
		this.img_width = img_width;
	}
	public String getImg_id() {
		return img_id;
	}
	public void setImg_id(String img_id) {
		this.img_id = img_id;
	}
	public String getUrl() {
		return url;
	}
	public void setUrl(String url) {
		this.url = url;
	}
	public String getResponse_code() {
		return response_code;
	}
	public void setResponse_code(String response_code) {
		this.response_code = response_code;
	}
}



  
 

package com.jyc;


/**
 * @author jiangyuchen
 * @date 2014-3-6
 */
public class Face {
	private static final String TAG = "JavaTest.Face";
	FacePositions position;
	FaceAttributes attribute;
	String tag;
	String face_id;
	
	public FacePositions getPosition() {
		return position;
	}
	public void setPosition(FacePositions position) {
		this.position = position;
	}
	public FaceAttributes getAttribute() {
		return attribute;
	}
	public void setAttribute(FaceAttributes attribute) {
		this.attribute = attribute;
	}
	public String getTag() {
		return tag;
	}
	public void setTag(String tag) {
		this.tag = tag;
	}
	public String getFace_id() {
		return face_id;
	}
	public void setFace_id(String face_id) {
		this.face_id = face_id;
	}
	public class FacePositions {
		Position mouth_right;
		Position mouth_left;
		Position center;
		Position nose;
		Position eye_left;
		Position eye_right;
		float height;
		float width;
		public Position getMouth_right() {
			return mouth_right;
		}
		public void setMouth_right(Position mouth_right) {
			this.mouth_right = mouth_right;
		}
		public Position getMouth_left() {
			return mouth_left;
		}
		public void setMouth_left(Position mouth_left) {
			this.mouth_left = mouth_left;
		}
		public Position getCenter() {
			return center;
		}
		public void setCenter(Position center) {
			this.center = center;
		}
		public Position getNose() {
			return nose;
		}
		public void setNose(Position nose) {
			this.nose = nose;
		}
		public Position getEye_left() {
			return eye_left;
		}
		public void setEye_left(Position eye_left) {
			this.eye_left = eye_left;
		}
		public Position getEye_right() {
			return eye_right;
		}
		public void setEye_right(Position eye_right) {
			this.eye_right = eye_right;
		}
		public float getHeight() {
			return height;
		}
		public void setHeight(float height) {
			this.height = height;
		}
		public float getWidth() {
			return width;
		}
		public void setWidth(float width) {
			this.width = width;
		}
	}
	
	public class FaceAttributes {
		Attribute race;
		Attribute gender;
		Attribute smiling;
		Attribute age;
		public Attribute getRace() {
			return race;
		}
		public void setRace(Attribute race) {
			this.race = race;
		}
		public Attribute getGender() {
			return gender;
		}
		public void setGender(Attribute gender) {
			this.gender = gender;
		}
		public Attribute getSmiling() {
			return smiling;
		}
		public void setSmiling(Attribute smiling) {
			this.smiling = smiling;
		}
		public Attribute getAge() {
			return age;
		}
		public void setAge(Attribute age) {
			this.age = age;
		}
		public class Attribute{
			public String getValue() {
				return value;
			}
			public void setValue(String value) {
				this.value = value;
			}
			public float getConfidence() {
				return confidence;
			}
			public void setConfidence(float confidence) {
				this.confidence = confidence;
			}
			public int getRange() {
				return range;
			}
			public void setRange(int range) {
				this.range = range;
			}
			String value;
			float confidence;
			int range;
		}
	}
}



  

package com.jyc;
/**
 * @author jiangyuchen
 * @date 2014-3-6
 */
public class Position {
	private static final String TAG = "JavaTest.Position";
	public float getX() {
		return x;
	}
	public void setX(float x) {
		this.x = x;
	}
	public float getY() {
		return y;
	}
	public void setY(float y) {
		this.y = y;
	}
	float x;
	float y;
}

執行輸出：

{"face":[{"position":{"mouth_right":{"y":21.687167,"x":57.765155},"mouth_left":{"y":20.749833,"x":52.425537},"center":{"y":18.583333,"x":56.205251},"height":10.166667,"width":14.558473,"nose":{"y":18.785333,"x":56.317422},"eye_left":{"y":14.81305,"x":52.951074},"eye_right":{"y":16.054433,"x":60.904535}},"attribute":{"race":{"value":"Asian","confidence":90.348},"gender":{"value":"Female","confidence":99.9999},"smiling":{"value":0.490444},"age":{"value":11,"range":5}},"tag":"","face_id":"403f40726858a195ea3aec08c4f05354"}],"session_id":"6cdc4eac5f86433f9ce041993df1555e","img_height":1001,"img_width":700,"img_id":"dc6e6d69d669e4bf20a111f58361fb3e","url":"http:\/\/d.hiphotos.baidu.com\/image\/w%3D2048\/sign=618830d52c738bd4c421b53195b386d6\/3c6d55fbb2fb4316d61e357222a4462309f7d3b1.jpg","response_code":200}
{"face":[{"attribute":{"age":{"confidence":0,"range":5,"value":"11"},"gender":{"confidence":99.9999,"range":0,"value":"Female"},"race":{"confidence":90.348,"range":0,"value":"Asian"},"smiling":{"confidence":0,"range":0,"value":"0.490444"}},"face_id":"403f40726858a195ea3aec08c4f05354","position":{"center":{"x":56.20525,"y":18.583332},"eye_left":{"x":52.951073,"y":14.81305},"eye_right":{"x":60.904533,"y":16.054434},"height":10.166667,"mouth_left":{"x":52.425537,"y":20.749832},"mouth_right":{"x":57.765156,"y":21.687166},"nose":{"x":56.31742,"y":18.785334},"width":14.558473},"tag":""}],"img_height":1001,"img_id":"dc6e6d69d669e4bf20a111f58361fb3e","img_width":700,"response_code":"200","session_id":"6cdc4eac5f86433f9ce041993df1555e","url":"http://d.hiphotos.baidu.com/image/w%3D2048/sign=618830d52c738bd4c421b53195b386d6/3c6d55fbb2fb4316d61e357222a4462309f7d3b1.jpg"}