标签：时间戳 ack array mvc one src javabean ota response
1、Jackson的使用
（1）概念
Jackson是目前比较好的json解析工具，还有阿里巴巴的fastjson等等
（2）导入依赖
<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind --> <dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> <version>2.9.8</version> </dependency>
（3）创建一个Teacher的实体类：
@Getter @Setter @ToString public class Teacher { private String teacherno; private String tname; private String major; private String prof; private String department; }
这里用到的是Lombok插件
（4）创建处理器：
@Controller @RequestMapping("/teacher") public class TeacherController { @GetMapping(value = "/t1",produces = "application/json;charset=utf-8")//中文乱码 @ResponseBody//加上之后就不会走视图解析器，返回的是一个字符串 public String testModelMap(ModelMap modelMap) throws JsonProcessingException { ObjectMapper objectMapper=new ObjectMapper(); Teacher teacher=new Teacher("202011","张","jisuanji","laoshi","xxgc"); String str=objectMapper.writeValueAsString(teacher); return str; } }
可以看出，返回的结果是一个json格式的字符串，在这里要处理中文乱码问题，因为返回的是一个字符串，因此不需要视图解析器，要将它屏蔽掉
（5）乱码问题优化
<mvc:annotation-driven> <mvc:message-converters register-defaults="true"> <bean class="org.springframework.http.converter.StringHttpMessageConverter"> <constructor-arg value="UTF-8"></constructor-arg> </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"></property> </bean> </property> </bean> </mvc:message-converters> </mvc:annotation-driven>
直接在springmvc.xml中配置，就不需要在每一个处理器中配置解决JSON的中文乱码的代码了
（6）RestController注解：
@RestController//只返回字符串 @RequestMapping("/teacher") public class TeacherController { @GetMapping(value = "/t1")//中文乱码 public String testModelMap(ModelMap modelMap) throws JsonProcessingException { ObjectMapper objectMapper=new ObjectMapper(); Teacher teacher=new Teacher("202011","张","jisuanji","laoshi","xxgc"); String str=objectMapper.writeValueAsString(teacher); return str; } }
不需要添加屏蔽视图解析器的代码，直接添加此注解，处理器就只返回字符串
2、返回集合
@RestController//只返回字符串 @RequestMapping("/teacher") public class TeacherController { @GetMapping(value = "/t1")//中文乱码 public String testModelMap(ModelMap modelMap) throws JsonProcessingException { ObjectMapper objectMapper=new ObjectMapper(); List<Teacher> teacherList=new ArrayList<Teacher>(); Teacher teacher1=new Teacher("202011","张","jisuanji","laoshi", "xxgc"); Teacher teacher2=new Teacher("202012","张","jisuanji","laoshi", "xxgc"); Teacher teacher3=new Teacher("202013","张","jisuanji","laoshi", "xxgc"); Teacher teacher4=new Teacher("202014","张","jisuanji","laoshi", "xxgc"); teacherList.add(teacher1); teacherList.add(teacher2); teacherList.add(teacher3); teacherList.add(teacher4); String str=objectMapper.writeValueAsString(teacherList); return str; } }
测试：
中括号代表一个集合，大括号代表一个json对象
3:、日期的格式化输出
（1）传统方式：
@RestController//只返回字符串 @RequestMapping("/teacher") public class TeacherController { @GetMapping(value = "/t1")//中文乱码 public String testModelMap(ModelMap modelMap) throws JsonProcessingException { ObjectMapper objectMapper=new ObjectMapper(); Date date=new Date(); SimpleDateFormat simpleDateFormat=new SimpleDateFormat(); return objectMapper.writeValueAsString(simpleDateFormat.format(date)); } }
(2)ObjectMapper 方式：
@RestController//只返回字符串 @RequestMapping("/teacher") public class TeacherController { @GetMapping(value = "/t1")//中文乱码 public String testModelMap(ModelMap modelMap) throws JsonProcessingException { ObjectMapper objectMapper=new ObjectMapper(); //不使用时间戳的方式 objectMapper.configure(SerializationFeature.WRITE_DATE_KEYS_AS_TIMESTAMPS,false); //自定义日期格式 SimpleDateFormat simpleDateFormat=new SimpleDateFormat("yyyy-MM-dd:ss"); objectMapper.setDateFormat(simpleDateFormat); Date date=new Date(); return objectMapper.writeValueAsString(date); } }
4、工具类
（1）定义工具类：
public class JsonUtils { public static String getJson(Object object,String dateFormat){ ObjectMapper objectMapper=new ObjectMapper(); //不使用时间戳的方式 objectMapper.configure(SerializationFeature.WRITE_DATE_KEYS_AS_TIMESTAMPS,false); //自定义日期格式 SimpleDateFormat simpleDateFormat=new SimpleDateFormat(dateFormat); objectMapper.setDateFormat(simpleDateFormat); try { return objectMapper.writeValueAsString(object); } catch (JsonProcessingException e) { e.printStackTrace(); } return null; } }
（2）测试工具类：
@RestController//只返回字符串 @RequestMapping("/teacher") public class TeacherController { @GetMapping(value = "/t1")//中文乱码 public String testModelMap(ModelMap modelMap) throws JsonProcessingException { Date date=new Date(); return JsonUtils.getJson(date,"yyyy-MM-dd HH:mm:ss"); } }
（3）如果只传递一个参数：
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 objectMapper=new ObjectMapper(); //不使用时间戳的方式 objectMapper.configure(SerializationFeature.WRITE_DATE_KEYS_AS_TIMESTAMPS,false); //自定义日期格式 SimpleDateFormat simpleDateFormat=new SimpleDateFormat(dateFormat); objectMapper.setDateFormat(simpleDateFormat); try { return objectMapper.writeValueAsString(object); } catch (JsonProcessingException e) { e.printStackTrace(); } return null; } }
上面的方法调用了另外一个方法，体现了代码的复用，只不过时间的格式已经默认
5、FastJson
（1）概念
是阿里开发的一款专门用于java开发的包，可以方便的实现json对象与javaBean对象的转换，实现javaBean对象与JSON字符串的转换、json字符串与java对象的转换
（2）导入依赖：
<dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> <version>2.10.0</version> </dependency>
（3）IDEA需要更新lib（https://www.cnblogs.com/zhai1997/p/12817048.html）
（4）测试：
@RestController//只返回字符串 @RequestMapping("/teacher") public class TeacherController { @GetMapping(value = "/t1")//中文乱码 public String testJson(){ List<Teacher> teacherList=new ArrayList<Teacher>(); Teacher teacher1=new Teacher("202011","张","jisuanji","laoshi", "xxgc"); Teacher teacher2=new Teacher("202012","张","jisuanji","laoshi", "xxgc"); Teacher teacher3=new Teacher("202013","张","jisuanji","laoshi", "xxgc"); Teacher teacher4=new Teacher("202014","张","jisuanji","laoshi", "xxgc"); teacherList.add(teacher1); teacherList.add(teacher2); teacherList.add(teacher3); teacherList.add(teacher4); String string=JSON.toJSONString(teacherList); return string; } }
mybatis（Jackson：Controller返回JSON数据（集合、日期、日期工具类）、FastJson）
标签：时间戳 ack array mvc one src javabean ota response
原文地址：https://www.cnblogs.com/zhai1997/p/12817279.html
