Jackson
前置准备
1.导入依赖
<!-- jackson -->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.14.0</version>
</dependency>
<!--fastJson 阿里开发的方便于 json与javaBean对象的转换 -->
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>fastjson</artifactId>
<version>1.2.60</version>
</dependency>
2.配置 解决json乱码问题
<?xml version="1.0" encoding="UTF8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:context="http://www.springframework.org/schema/context" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.2.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.2.xsd http://www.springframework.org/schema/context https://www.springframework.org/schema/context/spring-context.xsd"> <!-- 自动扫描包，并让下面的包注解生效 记得配置mvc和context的约束 --> <context:component-scan base-package="com.zxy.controller"/> <!--解决json 乱码配置--> <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> </beans>
web.xml(配置MVC核心和乱码过滤)
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" version="4.0"> <!--1.配置DispatchServlet--> <servlet> <servlet-name>springmvc</servlet-name> <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class> <init-param> <param-name>contextConfigLocation</param-name> <param-value>classpath:springmvc-servlet.xml</param-value> </init-param> <load-on-startup>1</load-on-startup> </servlet> <servlet-mapping> <servlet-name>springmvc</servlet-name> <url-pattern>/</url-pattern> </servlet-mapping> <!-- 配置中文乱码过滤器 --> <filter> <filter-name>characterEncodingFilter</filter-name> <filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class> <!-- 初始化过滤器 --> <init-param> <param-name>encoding</param-name> <param-value>UTF-8</param-value> </init-param> </filter> <filter-mapping> <filter-name>characterEncodingFilter</filter-name> <!-- 拦截所有请求 --> <url-pattern>/*</url-pattern> </filter-mapping> </web-app>
UserController (使用书写原码的思想 重载类 避免重返书写重复代码)
package com.zxy.controller; import com.alibaba.fastjson.JSON; import com.zxy.pojo.User; import com.zxy.utils.JsonUtils; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.RestController; import java.util.ArrayList; import java.util.Date; @RestController //此类下面的所有的返回值都是字符串 @Controller public class UserController { @RequestMapping("/j1") // @ResponseBody //有他就不会走视图解析器了，胡直接返回一个字符串 和 @RestController 二者有一个就可以 public String json1() { ArrayList<User> userlist = new ArrayList<>(); User user1 = new User("1",3,"男"); User user2 = new User("2",3,"男"); User user3 = new User("3",3,"男"); User user4 = new User("4",3,"男"); userlist.add(user1); userlist.add(user2); userlist.add(user3); userlist.add(user4); return JsonUtils.getJson(userlist); } @RequestMapping("/j2") public String json2() { Date date = new Date(); //将实现过程代码分离 return JsonUtils.getJson(date); } //使用阿里fastJson 需要导入fastjson的依赖 @RequestMapping("/j3") public String json3() { ArrayList<User> userlist = new ArrayList<>(); User user1 = new User("1",3,"男"); User user2 = new User("2",3,"男"); User user3 = new User("3",3,"男"); User user4 = new User("4",3,"男"); userlist.add(user1); userlist.add(user2); userlist.add(user3); userlist.add(user4); String string = JSON.toJSONString(userlist); return string; } }
JsonUtils (使用书写原码的思想 重载类 避免重返书写重复代码)
package com.zxy.utils; import com.fasterxml.jackson.core.JsonProcessingException; import com.fasterxml.jackson.databind.ObjectMapper; import com.fasterxml.jackson.databind.SerializationFeature; import java.text.SimpleDateFormat; public class JsonUtils { //重载的方法 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(); //显示时间 //不使用时间戳的方法 mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS,false); //自定义日期的格式 SimpleDateFormat sdf = new SimpleDateFormat(dateFormat); mapper.setDateFormat(sdf); try { return mapper.writeValueAsString(object); } catch (JsonProcessingException e) { e.printStackTrace(); } return null; } }
User
package com.zxy.pojo; public class User { private String name; private int age; private String sex; public User() { } public User(String name, int age, String sex) { this.name = name; this.age = age; this.sex = sex; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getAge() { return age; } public void setAge(int age) { this.age = age; } public String getSex() { return sex; } public void setSex(String sex) { this.sex = sex; } @Override public String toString() { return "User{" + "name='" + name + '\'' + ", age=" + age + ", sex='" + sex + '\'' + '}'; } }
