JSON的語法格式?
*物件表示為鍵值對
*資料由逗號分割
*花括號保存物件
*方括號保存陣列
實體:
{"username":"十五萬","age":"11","sex":"男"}
追加:
JSON是一種輕量級的資料交換格式，它基于JavaScript的一個子集.
JSON 是 JS 物件的字串表示法，它使用文本表示一個 JS 物件的資訊，本質是一個字串。
JSON 和 JS 物件互轉(這里我們用jackson這個,不用fastjson!)
var user = {
name :"孫偉浩",
age : 16,
sex : "男"
};
console.log(user);
js物件通過.stringfy(引數)來得到var形式的jason字串
var str = JSON.stringify(user);
console.log(str);
用.parse(引數)方法把json字串轉成js物件形式
var obj = JSON.parse(str);
console.log(obj);
package com.example.fuxi.controller;
import com.example.fuxi.pojo.User;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
@Controller
public class UserController {
//produce:指定回應體的回傳型別和編碼-----防止回傳到頁面亂碼
@RequestMapping(value = "/json",produces = "application/json;charset=utf-8") //String 的轉換格式 produces = "text/html;charset=utf-8"
@ResponseBody
public String json1(){
User user = new User("十五萬","11","男");
ObjectMapper mapper = new ObjectMapper(); //需要一個jackson的物件映射器,也就是一個類,可以將物件轉換為字串
String userJson = null;
try {
userJson = mapper.writeValueAsString(user); //將一個java物件,轉換成字串
} catch (JsonProcessingException e) {
e.printStackTrace();
}
System.out.println(userJson);
return userJson;
}
}
對上面進行簡化如下
@RequestMapping(value = "/json2",produces = "application/json;charset=utf-8") //String 的轉換格式 produces = "text/html;charset=utf-8"
@ResponseBody
public String json2 () throws JsonProcessingException {
User user = new User("李太白","26","男");
return new ObjectMapper().writeValueAsString(user);
}
list集合轉換json
@RequestMapping(value = "/json3",produces = "application/json;charset=utf-8") //String 的轉換格式 produces = "text/html;charset=utf-8"
@ResponseBody
public String json3 () throws JsonProcessingException {
List<User> list = new ArrayList<User>();
list.add(new User("李太白1","26","男"));
list.add(new User("李太白2","25","男"));
list.add(new User("李太白3","24","男"))
list.add(new User("李太白4","23","男"));
return new ObjectMapper().writeValueAsString(list);
}
通過組態檔設定json格式
<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerMapping" />
<bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter">
<property name="messageConverters">
<list>
<bean class="org.springframework.http.converter.StringHttpMessageConverter">
<property name="supportedMediaTypes">
<list>
<value>text/html; charset=UTF-8</value>
<value>application/json;charset=UTF-8</value>
</list>
</property>
</bean>
<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<property name="supportedMediaTypes">
<list>
<value>text/html; charset=UTF-8</value>
<value>application/json;charset=UTF-8</value>
</list>
</property>
</bean>
</list>
</property>
</bean>
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