java解析json格式数据java返回json数据
⽅式1、⾃⼰全部⼿动写
这种⽅法是⽤servlet的内置对象response返回到前台。注意，java⾥的引号要⽤的转义字符“\”）protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setCharacterEncoding("utf-8");
response.setContentType("application/json;charset=utf-8");
PrintWriter out = Writer();
//或:ServletOutputStream out = OutputStream();
//但两个不要⼀起⽤!
out.write("[{\"id\":1,\"name\":default}]");
out.flush();
out.close();
}
⽅式2、jackson解析，SpringMVC内置的解析器
⽰例1
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { response.setCharacterEncoding("utf-8");
response.setContentType("application/json;charset=utf-8");
PrintWriter out = Writer();
Object result = new Object();
// jackson核⼼对象
ObjectMapper objectMap = new ObjectMapper();
objectMap.writeValue(out, result );
}
⽰例2
public class JackSonTest {
//解析
@Test
public void test1() throws Exception{
// 对象嵌套数组嵌套对象
String json1 = "{\"id\":1,\"name\":\"JAVAEE-1703\",\"stus\":[{\"id\":101,\"name\":\"刘⼀\",\"age\":16}]}";
// 数组
String json2 = "[\"北京\",\"天津\",\"杭州\"]";
//1、
ObjectMapper mapper=new ObjectMapper();
Grade adValue(json1, Grade.class);
System.out.println(grade);
//2、
ArrayList<String> adValue(json2,
new TypeReference<ArrayList<String>>() {
});
System.out.println(list);
}
//⽣成
@Test
public void test2() throws JsonProcessingException{
ArrayList<Student> list=new ArrayList<>();
for(int i=1;i<3;i++){
list.add(new Student(101+i, "码⼦", 20+i));
}
Grade grade=new Grade(100001,"张三", list);
ObjectMapper mapper=new ObjectMapper();
//将对象转换为JSON格式字符串
String json=mapper.writeValueAsString(grade);
System.out.println(json);
}
}
相关jar包
jackson-core-2.2.3.jar
jackson-annotations-2.2.3.jar
jackson-databind-2.2.3.jar
⽅式3、⽤Spring框架@ResponseBody的注解
@RequestMapping("/login")
@ResponseBody
public User login(User user){
return user;
}
User字段：userName pwd。前台接收到的数据为：'{"userName":"xxx","pwd":"xxx"}'效果等同于如下代码：
@RequestMapping("/login")
public void login(User user, HttpServletResponse response){
Writer.write(JSONObject.fromObject(user).toString());
}
⽅式4、传统的JSON解析
⽣成json字符串
public static String createJsonString(String key, Object value) {
JSONObject jsonObject = new JSONObject();
jsonObject.put(key, value);
String();
}
json解析，⽰例1
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import org.json.JSONArray;
import org.json.JSONObject;
import json.domain.Person;
/**
* 完成对json数据的解析
*
*/
public class JsonTools {
public static Person getPerson(String key, String jsonString) {
Person person = new Person();
try {
JSONObject jsonObject = new JSONObject(jsonString);
JSONObject personObject = JSONObject("person");
person.Int("id"));
person.String("name"));
person.String("address"));
} catch (Exception e) {
// TODO: handle exception
}
return person;
}
public static List getPersons(String key, String jsonString) {
List list = new ArrayList();
try {
JSONObject jsonObject = new JSONObject(jsonString);
// 返回json的数组
JSONArray jsonArray = JSONArray(key);
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonObject2 = JSONObject(i);
Person person = new Person();
person.Int("id"));
person.String("name"));
person.String("address"));
list.add(person);
}
} catch (Exception e) {
// TODO: handle exception
}
return list;
}
public static List getList(String key, String jsonString) {
List list = new ArrayList();
try {
JSONObject jsonObject = new JSONObject(jsonString);
JSONArray jsonArray = JSONArray(key);
for (int i = 0; i < jsonArray.length(); i++) {
String msg = String(i);
list.add(msg);
}
} catch (Exception e) {
// TODO: handle exception
}
return list;
}
public static List> listKeyMaps(String key,
String jsonString) {
List> list = new ArrayList>();
try {
JSONObject jsonObject = new JSONObject(jsonString);
JSONArray jsonArray = JSONArray(key);
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonObject2 = JSONObject(i);
Map map = new HashMap();
Iterator iterator = jsonObject2.keys();
while (iterator.hasNext()) {
String json_key = ();
Object json_value = (json_key);
if (json_value == null) {
json_value = "";
}
map.put(json_key, json_value);
}
list.add(map);
}
} catch (Exception e) {
// TODO: handle exception
}
return list;
}
}
json解析，⽰例2
public class JSONTest {
/
/解析JSON
@Test
public void test1() throws JSONException{
//对象嵌套数组嵌套对象
String json1="{'id':1,'name':'JAVAEE-1703','stus':[{'id':101,'name':'刘⼀','age':16}]}";
//数组
String json2="['北京','天津','杭州']";
//1、
//解析第⼀层---对象
JSONObject jObject1=new JSONObject(json1);
Grade grade=new Grade();
grade.Int("id"));
grade.String("name"));
ArrayList<Student> stus=new ArrayList<>();
grade.setStus(stus);
//解析第⼆层----数组
JSONArray JSONArray("stus");
//遍历数组获取元素----对象
for(int i=0;i<jsonArray2.length();i++){
//解析第三层----对象
JSONObject JSONObject(i);
Student student=new Int("id"), String("name"), Int("age")); Stus().add(student);
}
System.out.println(grade);
//获取当前对象的所有属性的迭代器对象
// Iterator<String> iterator=jObject1.keys();
// while (iterator.hasNext()) {
// String key = ();
// System.out.println("属性："+key);
// }
//2、
//获取数组对象
JSONArray jArray=new JSONArray(json2);
ArrayList<String> list=new ArrayList<>();
//遍历获取元素
for(int i=0;i<jArray.length();i++){
//jArray.optString(i);//等价于getXXX
list.String(i));
}
System.out.println("解析结果："+list);
}
//⽣成JSON
@Test
public void test2() throws JSONException{
JSONObject jo1=new JSONObject();
jo1.put("id", 1001);
jo1.put("name", "范⽼");
jo1.put("age", 20);
JSONObject jo2=new JSONObject();
jo2.put("id", 1002);
jo2.put("name", "平平");
jo2.put("age", 19);
JSONArray ja2=new JSONArray();
ja2.put(jo1);
ja2.put(jo2);
JSONObject jo3=new JSONObject();
jo3.put("id", 11);
jo3.put("name", "JAVAEE-1704");
jo3.put("stus",ja2);
String String();
System.out.println(json);
}
}
⽅式5、JSON解析之GSON
⽣成JSON字符串
le.gson.Gson;
public class JsonUtils {
public static String createJsonObject(Object obj) {
Gson gson = new Gson();
String str = Json(obj);
return str;
}
}
解析，⽰例1
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
le.gson.Gson;
flect.TypeToken;
;
public class GsonTools {
public GsonTools() {
// TODO Auto-generated constructor stub
}
/**
* @param
* @param jsonString
* @param cls
* @return
*/
public static T getPerson(String jsonString, Class cls) {
T t = null;
try {
Gson gson = new Gson();
t = gson.fromJson(jsonString, cls);
} catch (Exception e) {
// TODO: handle exception
}
return t;
}
/**
* 使⽤Gson进⾏解析 List
*
* @param
* @param jsonString
* @param cls
* @return
*/
public static List getPersons(String jsonString, Class cls) { List list = new ArrayList();
try {
Gson gson = new Gson();
list = gson.fromJson(jsonString, new TypeToken>() { }.getType());
} catch (Exception e) {
}
return list;
}
/**
* @param jsonString
* @return
*/
public static List getList(String jsonString) {
List list = new ArrayList();
try {
Gson gson = new Gson();
list = gson.fromJson(jsonString, new TypeToken>() {
}.getType());
} catch (Exception e) {
// TODO: handle exception
}
return list;
}
public static List> listKeyMaps(String jsonString) {
List> list = new ArrayList>();
try {
Gson gson = new Gson();
list = gson.fromJson(jsonString,
new TypeToken>>() {
}.getType());
} catch (Exception e) {
// TODO: handle exception
}
return list;
}
}
⽰例2
public class GSONTest {
//解析
@Test
public void test1() {
// 对象嵌套数组嵌套对象
String json1 = "{'id':1,'name':'JAVAEE-1703','stus':[{'id':101,'name':'刘⼀','age':16}]}";
// 数组
String json2 = "['北京','天津','杭州']";
Gson gson=new Gson();
/
/1、
//解析对象：第⼀个参数：待解析的字符串第⼆个参数结果数据类型的Class对象 Grade grade=gson.fromJson(json1, Grade.class);
System.out.println(grade);
//2、
//解析数组要求使⽤Type
ArrayList<String> list=gson.fromJson(json2,
new TypeToken<ArrayList<String>>(){}.getType());
System.out.println(list);
}
//⽣成
@Test
public void test2(){
ArrayList<Student> list=new ArrayList<>();
for(int i=1;i<3;i++){
list.add(new Student(101+i, "码⼦", 20+i));
}
fastjson字符串转数组Grade grade=new Grade(100001,"张三", list);
Gson gson=new Gson();
//将对象转换为诶JSON格式字符串
String Json(grade);
System.out.println(json);
}
}
⽅式6、JSON解析之FastJSON
⽰例1
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.TypeReference;
public class JsonTool {
public static T getPerson(String jsonstring, Class cls) {
T t = null;
try {
t = JSON.parseObject(jsonstring, cls);
} catch (Exception e) {
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