JSON
- JSON(JavaScript Object Notation, JS 对象标记) 它是一种广泛使用的轻量级数据交换格式
- 使用完全独立于编程语言的语言存储和表示数据
- 简洁清晰的层次结构使层次结构简洁明了 JSON 成为理想的数据交换语言
- 易于阅读和编写，也易于机器分析和生成，有效提高网络传输效率
JSON 用于保存键值对 JavaScript 对象的一种方式
{"name": "yl"} {"age": "11"} {"city": "南京"} var obj = {a: 'yl', b: 'nj'}; //对象 var json = '{"a": "yl", "b": "njorld"}'; //JSON 字符串 Jackson
javascript与json的相互转换
<script type="text/javascript"> var user = {
name:"好海", age:19, city:"北京" }; //将js对象转换为json对象 var json = JSON.stringify(user) console.log(json); //将json解析为js对象 var js = JSON.parse(json) console.log(js); </script> 解决JSON乱码
导入jackson依赖
<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind --> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> <version>2.13.3</version> </dependency> 1.配置编码
span class="token comment">//produces:指定响应体返回类型和编码
@RequestMapping(value = "/json1",produces = "application/json;charset=utf-8")
2.在springmvc-servlet.xml中配置
<mvc:annotation-driven>
<mvc:message-converters register-defaults="true">
<bean class="org.springframework.http.converter.StringHttpMessageConverter">
<constructor-arg value="UTF-8"/>
</bean>
<bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
<property name="objectMapper">
<bean class="org.springframework.http.converter.json.Jackson2ObjectMapperFactoryBean">
<property name="failOnEmptyBeans" value="false"/>
</bean>
</property>
</bean>
</mvc:message-converters>
</mvc:annotation-driven>
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.yl.pojo.User;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
@Controller
public class UserController {
//produces:指定响应体返回类型和编码
@RequestMapping(value = "/json1")
@ResponseBody //不进入视图解析器，直接返回一个字符串
public String json1() throws JsonProcessingException {
//创建一个jackson的对象映射器，用来解析数据
ObjectMapper mapper = new ObjectMapper();
//创建一个对象
User user = new User("延边", 3, "男");
//将我们的对象解析成为json格式
String str = mapper.writeValueAsString(user);
//由于@ResponseBody注解，这里会将str转成json格式返回；十分方便
return str;
}
}
添加工具类
package com.yl.utils; import com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.databind.ObjectMapper; import com.fasterxml.jackson.databind.SerializationFeature; import java.text.SimpleDateFormat; import java.util.ArrayList; import java.util.List; public class JsonUtils { public static String getJson(Object object){ return getJson(object,"yyyy-MM-dd HH:mm:ss"); } public static String getJson(Object object,String dateFormat){ ObjectMapper mapper = new ObjectMapper(); //不使用时间戳 mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false); //自定义日期格式 SimpleDateFormat sdf = new SimpleDateFormat(dateFormat); mapper.setDateFormat(sdf); try { return mapper.writeValueAsString(object); } catch (JsonProcessingException e) { e.printStackTrace(); } return null; } }
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import com.yl.pojo.User;
import com.yl.utils.JsonUtils;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
//@Controller //进入视图解析器
@RestController //直接返回字符串
public class UserController {
//produces:指定响应体返回类型和编码
@RequestMapping(value = "/json1")
//@ResponseBody //不进入视图解析器，直接返回一个字符串(配合Controller使用)
public String json1() throws JsonProcessingException {
//创建一个jackson的对象映射器，用来解析数据
ObjectMapper mapper = new ObjectMapper();
//创建一个对象
User user = new User("延边", 3, "男");
//将我们的对象解析成为json格式
String str = mapper.writeValueAsString(user);
//由于@ResponseBody注解，这里会将str转成json格式返回；十分方便
return str;
}
@RequestMapping(value = "/json2")
public String json2() throws JsonProcessingException {
//创建一个jackson的对象映射器，用来解析数据
ObjectMapper mapper = new ObjectMapper();
List<User> userList = new ArrayList<User>();
//创建一个对象
User user = new User("延边", 3, "男");
User user2 = new User("延边2", 13, "男");
userList.add(user);
userList.add(user2);
return JsonUtils.getJson(userList);
}
@RequestMapping(value = son3")
public String json3() throws JsonProcessingException {
Date date = new Date();
return JsonUtils.getJson(date, "yyyy-MM-dd HH:mm:ss");
}
}