前臺如何獲取列舉型別的值
阿新 • • 發佈：2019-01-25
用springmvc+fastjson如何傳遞列舉型別嗎？
下面是測試用的列舉類：
通常的做法我們只能取出A或B....
public enum TestEnum{ A(1, "1-100"), B(2,"2-200"), C(3, "3-300"), D(4, "4-400"), E(5, "5-500"); private Integer code; private String desc; TestEnum(Integer code, String desc) { this.code = code; this.desc = desc; } public Integer getCode() { return code; } public String getDesc() { return desc; } }
統一返回的包裝類：
public class Result { private Integer id; private TestEnum testEnum; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public TestEnum getTestEnum() { return testEnum; } public void setTestEnum(TestEnum testEnum) { this.testEnum = testEnum; } public Result(Integer id, TestEnum testEnum) { this.id = id; this.testEnum = testEnum; } }
兩種方法：
第一種：在Controller中直接操作
@Controller public class TestController { @RequestMapping("/") public String home(Model model){ return "index"; } @RequestMapping("/ajax") @ResponseBody public String ajax(){ SerializeConfig config = new SerializeConfig(); config.configEnumAsJavaBean(TestEnum.class); Result result = new Result(100, TestEnum.A); return JSON.toJSONString(result,config); } }
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<body>
<h2>Hello World!</h2>
<body>
<div>
測試
</div>
<script type="text/javascript" src="http://cdn.bootcss.com/jquery/3.1.0/jquery.min.js"></script>
<script>
$.ajax({
url:"/ajax",
type:"POST",
contentType:"application/x-www-form-urlencoded",
success:function (data) {
alert(data.testEnum.desc);
}
});
</script>
</body>
</body>
</html>第二種：通過toString()方法和配置檔案操作
（1）springmvc.xml新增轉換配置
<!-- 註解驅動 -->
<mvc:annotation-driven>
<mvc:message-converters>
<bean class="org.springframework.http.converter.StringHttpMessageConverter">
<constructor-arg value="UTF-8" index="0"/><!--避免出現亂碼 -->
<property name="supportedMediaTypes">
<list>
<value>application/json;charset=UTF-8</value>
</list>
</property>
</bean>
<bean class="com.alibaba.fastjson.support.spring.FastJsonHttpMessageConverter">
<property name="supportedMediaTypes">
<list>
<value>text/html;charset=UTF-8</value>
<value>application/json</value>
</list>
</property>
<property name="fastJsonConfig">
<bean class="com.alibaba.fastjson.support.config.FastJsonConfig">
<property name="features">
<list>
<value>AllowArbitraryCommas</value>
<value>AllowUnQuotedFieldNames</value>
</list>
</property>
<property name="charset" value="UTF-8"/>
<property name="dateFormat" value="yyyy-MM-dd HH:mm:ss"/>
<property name="serializerFeatures">
<list>
<value>WriteDateUseDateFormat</value>
<!--消除對同一物件迴圈引用的問題，預設為false-->
<value>DisableCircularReferenceDetect</value>
<!--關鍵-->
<value>WriteEnumUsingToString</value>
</list>
</property>
</bean>
</property>
</bean>
</mvc:message-converters>
</mvc:annotation-driven>（2）重寫列舉類的toString()
public enum TestEnum{
//省略。。。
@Override
public String toString() {
return "{'code':'"+this.code+"','desc':'"+this.desc+"'}";
}
//不要把單引號改成\雙引號,這樣當返回給前端json字串，json字串轉成物件時會報格式不正確的錯誤：
// @Override
// public String toString() {
// return "{\"code\":"+this.code+",\"desc\":"+this.desc+"}";
// }
}(3)控制層
@Controller
public class TestController {
@RequestMapping("/")
public String home(Model model){
return "index";
}
@RequestMapping("/ajax")
@ResponseBody
public Result ajax(){
Result result = new Result(100, TestEnum.A);
return result;
}
}(4)前臺頁面取值
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<body>
<h2>Hello World!</h2>
<body>
<div>
測試
</div>
<script type="text/javascript" src="http://cdn.bootcss.com/jquery/3.1.0/jquery.min.js"></script>
<script>
$.ajax({
url:"/ajax",
type:"POST",
contentType:"application/x-www-form-urlencoded",
success:function (data) {
alert(data);
var jsonObject =eval("("+ data +")");
alert(jsonObject.testEnum);
var testEnum = jsonObject.testEnum;
var em =eval('('+ testEnum +')');
//這一步使用“var em =JSON.parse(testEnum);”也會發生錯誤。
alert(em.desc);
}
});
</script>
</body>
</body>
</html>
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我最近也迷茫了，照做了。師兄沒有騙我，餓了兩天後，我也清楚的認識到自己究竟想要什麼啦。我想要吃飯。