一、阿里巴巴FastJson是一个Json处理工具包,包括“序列化”和“反序列化”两部分,它具备如下特征:
速度最快,测试表明,fastjson具有极快的性能,超越任其他的Java Json parser。包括自称最快的JackJson;
功能强大,完全支持Java Bean、集合、Map、日期、Enum,支持范型,支持自省;无依赖,能够直接运行在Java SE 5.0以上版本;支持Android;开源 (Apache 2.0)
Fastjson API入口类是com.alibaba.fastjson.JSON,常用的序列化操作都可以在JSON类上的静态方法直接完成。
public static final Object parse(String text); // 把JSON文本parse为JSONObject或者JSONArray
public static final JSONObject parseObject(String text); // 把JSON文本parse成JSONObject
public static final T parseObject(String text, Class clazz); // 把JSON文本parse为JavaBean
public static final JSONArray parseArray(String text); // 把JSON文本parse成JSONArray
public static final List parseArray(String text, Class clazz); //把JSON文本parse成JavaBean集合
public static final String toJSONString(Object object); // 将JavaBean序列化为JSON文本
public static final String toJSONString(Object object, boolean prettyFormat); // 将JavaBean序列化为带格式的JSON文本
public static final Object toJSON(Object javaObject); 将JavaBean转换为JSONObject或者JSONArray。
二、FastJson解析JSON步骤
A、服务器端将数据转换成json字符串
首先、服务器端项目要导入阿里巴巴的fastjson的jar包至builtPath路径下(这些可以到fastjson官网下载:http://code.alibabatech.com/wiki/display/FastJSON/Home-zh)
之FastJson解析" title="JSON
public static String createJsonString(Object value)
{
String alibabaJson = JSON.toJSONString(value);
return alibabaJson;
}
B、客户端将json字符串转换为相应的javaBean
首先客户端也要导入fastjson的两个jar包
1、客户端获取json字符串
public class HttpUtil
{
public static String getJsonContent(String urlStr)
{
try
{// 获取HttpURLConnection连接对象
URL url = new URL(urlStr);
HttpURLConnection httpConn = (HttpURLConnection) url
.openConnection();
// 设置连接属性
httpConn.setConnectTimeout(3000);
httpConn.setDoInput(true);
httpConn.setRequestMethod("GET");
// 获取相应码
int respCode = httpConn.getResponseCode();
if (respCode == 200)
{
return ConvertStream2Json(httpConn.getInputStream());
}
}
catch (MalformedURLException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
return "";
}
private static String ConvertStream2Json(InputStream inputStream)
{
String jsonStr = "";
// ByteArrayOutputStream相当于内存输出流
ByteArrayOutputStream out = new ByteArrayOutputStream();
byte[] buffer = new byte[1024];
int len = 0;
// 将输入流转移到内存输出流中
try
{
while ((len = inputStream.read(buffer, 0, buffer.length)) != -1)
{
out.write(buffer, 0, len);
}
// 将内存流转换为字符串
jsonStr = new String(out.toByteArray());
}
catch (IOException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
return jsonStr;
}
}
2、使用泛型获取javaBean(核心函数)
public static T getPerson(String jsonString, Class cls) {
T t = null;
try {
t = JSON.parseObject(jsonString, cls);
} catch (Exception e) {
// TODO: handle exception
}
return t;
}
public static List getPersons(String jsonString, Class cls) {
List list = new ArrayList();
try {
list = JSON.parseArray(jsonString, cls);
} catch (Exception e) {
}
return list;
}
public static List> listKeyMaps(String jsonString) {
List> list = new ArrayList>();
try {
list = JSON.parseObject(jsonString,
new TypeReference>>() {
});
} catch (Exception e) {
// TODO: handle exception
}
return list;
}
eg: 4种常用类型:JavaBean,List<JavaBean>,List<String>,List<Map<String,Object>
class FastJsonTest {
public static void main(String[] args) {
// 构建用户geust
User guestUser = new User();
guestUser.setName("guest");
guestUser.setAge(28);
// 构建用户root
User rootUser = new User();
rootUser.setName("root");
guestUser.setAge(35);
// 构建用户组对象
UserGroup group = new UserGroup();
group.setName("admin");
group.getUsers().add(guestUser);
group.getUsers().add(rootUser);
// 用户组对象转JSON串
String jsonString = JSON.toJSONString(group);
System.out.println("jsonString:" + jsonString);
// JSON串转用户组对象
UserGroup group2 = JSON.parseObject(jsonString, UserGroup.class);
System.out.println("group2:" + group2);
// 构建用户对象数组
User[] users = new User[2];
users[0] = guestUser;
users[1] = rootUser;
// 用户对象数组转JSON串
String jsonString2 = JSON.toJSONString(users);
System.out.println("jsonString2:" + jsonString2);
// JSON串转用户对象列表
List<User> users2 = JSON.parseArray(jsonString2, User.class);
System.out.println("users2:" + users2);
}
}
结果:jsonString:{"name":"admin","users":[{"age":35,"name":"guest"},{"age":0,"name":"root"}]}
group2:UserGroup [name=admin, users=[User [name=guest, age=35], User [name=root, age=0]]]
jsonString2:[{"age":35,"name":"guest"},{"age":0,"name":"root"}]
users2:[User [name=guest, age=35], User [name=root, age=0]]
String jsonStr = "[{\"JACKIE_ZHANG\":\"张学友\"},{\"ANDY_LAU\":\"刘德华\"},{\"LIMING\":\"黎明\"},{\"Aaron_Kwok\":\"郭富城\"}]" ;
//做5次测试
for(int i=0,j=5;i<j;i++)
{
JSONObject jsonObject = JSONObject.parseObject(jsonStr) ;
for(java.util.Map.Entry<String,Object> entry:jsonObject.entrySet()){
System.out.print(entry.getKey()+"-"+entry.getValue()+"\t");
}
System.out.println();//用来换行
}
LIMING-黎明 Aaron_Kwok-郭富城JACKIE_ZHANG-张学友ANDY_LAU-刘德华
Aaron_Kwok-郭富城 ANDY_LAU-刘德华LIMING-黎明JACKIE_ZHANG-张学友
Aaron_Kwok-郭富城 JACKIE_ZHANG-张学友ANDY_LAU-刘德华LIMING-黎明
LIMING-黎明 ANDY_LAU-刘德华JACKIE_ZHANG-张学友Aaron_Kwok-郭富城
JACKIE_ZHANG-张学友 LIMING-黎明ANDY_LAU-刘德华Aaron_Kwok-郭富城
//做5次测试
for(int i=0,j=5;i<j;i++)
{
JSONArray jsonArray = JSONArray.parseArray(jsonStr);
for(int k=0;k<jsonArray.size();k++){
System.out.print(jsonArray.get(k) + "\t");
}
System.out.println();//用来换行
}
{"JACKIE_ZHANG":"张学友"} {"ANDY_LAU":"刘德华"}{"LIMING":"黎明"}{"Aaron_Kwok":"郭富城"}
{"JACKIE_ZHANG":"张学友"} {"ANDY_LAU":"刘德华"}{"LIMING":"黎明"}{"Aaron_Kwok":"郭富城"}
{"JACKIE_ZHANG":"张学友"} {"ANDY_LAU":"刘德华"}{"LIMING":"黎明"}{"Aaron_Kwok":"郭富城"}
{"JACKIE_ZHANG":"张学友"} {"ANDY_LAU":"刘德华"}{"LIMING":"黎明"}{"Aaron_Kwok":"郭富城"}
{"JACKIE_ZHANG":"张学友"} {"ANDY_LAU":"刘德华"}{"LIMING":"黎明"}{"Aaron_Kwok":"郭富城"}
//做5次测试
for(int i=0,j=5;i<j;i++)
{
JsonObject jsonObject = (JsonObject) new JsonParser().parse(jsonStr);
for(java.util.Map.Entry<String,JsonElement> entry:jsonObject.entrySet()){
System.out.print(entry.getKey()+"-"+entry.getValue()+"\t");
}
System.out.println();//用来换行
}
JACKIE_ZHANG-"张学友" ANDY_LAU-"刘德华" LIMING-"黎明" Aaron_Kwok-"郭富城"
JACKIE_ZHANG-"张学友" ANDY_LAU-"刘德华" LIMING-"黎明" Aaron_Kwok-"郭富城"
JACKIE_ZHANG-"张学友" ANDY_LAU-"刘德华" LIMING-"黎明" Aaron_Kwok-"郭富城"
JACKIE_ZHANG-"张学友" ANDY_LAU-"刘德华" LIMING-"黎明" Aaron_Kwok-"郭富城"
JACKIE_ZHANG-"张学友" ANDY_LAU-"刘德华" LIMING-"黎明" Aaron_Kwok-"郭富城"