java解析json复杂数据的方法详解
作者：爱码少年
一、简单分析
对照需求，可以简单分解为如下步骤：
每天23点自动运行任务，实现方式：@Scheduled、cron表达式
获取每篇文章的访问量，实现方式：api接口、数据解析
记录每篇文章的访问量，实现方式：javaBean、JDBC、ORM框架
二、具体实现一
步骤1、3代码实现比较常见，不再详细描述具体实现。
下面我们详细描述步骤2的具体实现
1. api接口
接口地址： https://blog.csdn.net/community/home-api/v1/get-business-list?page={页号}&size={当前页数据条数}&businessType=blog&username={用户名}
2. 接口返回
以下面的接口为例：
https://blog.csdn.net/community/home-api/v1/get-business-list?page=1&size=5&businessType=blog&username=qq_16127313
返回数据如下：
{
"code": 200,
"message": "success",
"traceId": "5a64396a-caf3-49ad-a6db-022c55660b75",
"data": {
"list": [
{
"articleId": 135244727,
"title": "java lambda表达式训练题一",
"description": "Lambda 表达式，也可称为闭包，它是推动 Java 8 发布的最重要新特性。Lambda 允许把函数作为一个方法的参数（函数作为参数传递进方法中）。使用 Lambda 表达式可以使代码变的更加简洁紧凑。",
"url": "https://blog.csdn.net/qq_16127313/article/details/135244727",
"type": 1,
"top": false,
"forcePlan": false,
"viewCount": 1019,
"commentCount": 0,
"editUrl": "https://editor.csdn.net/md?articleId=135244727",
"postTime": "2023-12-27 18:07:30",
"diggCount": 7,
"formatTime": "2023.12.27",
"picList": [
"https://img-blog.csdnimg.cn/direct/d59c68b950754e879914b5319cd1b53f.png"
],
"collectCount": 8
},
{
"articleId": 135173565,
"title": "二维码初体验 com.google.zxing 实现续 - web api封装",
"description": "在 二维码初体验 com.google.zxing 实现 我们实现了二维码的生成，但是大部分情况下，二维码的相关功能是作为API接口来提供服务的。我们下面便演示在springboot、Knife4j下封装api接口来实现二维码生成功能。如何使用下面的备份文件恢复成原始的项目代码，请移步查阅：神奇代码恢复工具-over-",
"url": "https://blog.csdn.net/qq_16127313/article/details/135173565",
"type": 1,
"top": false,
"forcePlan": false,
"viewCount": 1693,
"commentCount": 0,
"editUrl": "https://editor.csdn.net/md?articleId=135173565",
"postTime": "2023-12-23 20:17:11",
"diggCount": 23,
"formatTime": "2023.12.23",
"picList": [
"https://img-blog.csdnimg.cn/direct/f0c994ca789a495a8c8c03d86d626f24.jpeg"
],
"collectCount": 23
},
{
"articleId": 135167613,
"title": "二维码初体验 com.google.zxing 实现",
"description": "Java 操作二维码的开源项目很多，如 SwetakeQRCode、BarCode4j、Zxing 等，这边以Zxing 为例进行介绍。选择需要生成QR原始文件，支持 “清除空白行及空格” 以减少二维码图片大小。支持输入文本内容，直接生成二维码代码结构QrCodeUI: 完整版本代码SimpleQrCodeUI：简化版本代码如何使用下面的备份文件恢复成原始的项目代码，请移步查阅：神奇代码恢复工具-over-",
"url": "https://blog.csdn.net/qq_16127313/article/details/135167613",
"type": 1,
"top": false,
"forcePlan": false,
"viewCount": 1081,
"commentCount": 0,
"editUrl": "https://editor.csdn.net/md?articleId=135167613",
"postTime": "2023-12-23 13:52:23",
"diggCount": 6,
"formatTime": "2023.12.23",
"picList": [
"https://img-blog.csdnimg.cn/direct/d3eeac85857543869dce8967c570bdc4.jpeg"
],
"collectCount": 11
},
{
"articleId": 135135799,
"title": "【随笔】MD5加密字符串、文件apache、springframework实现",
"description": "【代码】【随笔】MD5加密字符串、文件commons-codec、springframework实现。",
"url": "https://blog.csdn.net/qq_16127313/article/details/135135799",
"type": 1,
"top": false,
"forcePlan": false,
"viewCount": 1507,
"commentCount": 0,
"editUrl": "https://editor.csdn.net/md?articleId=135135799",
"postTime": "2023-12-21 17:29:54",
"diggCount": 9,
"formatTime": "2023.12.21",
"picList": [
"https://img-blog.csdnimg.cn/direct/dc26b7f1c731494f80c8c3b3badfa95d.jpeg"
],
"collectCount": 9
},
{
"articleId": 135087188,
"title": "【随笔】java工程中JSON 字符串格式化输出",
"description": "json字符串格式化输出fastjson、gson、jackson实现。",
"url": "https://blog.csdn.net/qq_16127313/article/details/135087188",
"type": 1,
"top": false,
"forcePlan": false,
"viewCount": 1198,
"commentCount": 0,
"editUrl": "https://editor.csdn.net/md?articleId=135087188",
"postTime": "2023-12-19 17:07:40",
"diggCount": 8,
"formatTime": "2023.12.19",
"picList": [
"https://img-blog.csdnimg.cn/direct/058249a1749e4ff5b62e1fcabf516c37.png"
],
"collectCount": 6
}
],
"total": 71
}
} 3. json 数据解析
在Java中，可以使用多种库来解析JSON数据。其中最常用的是fastjson、gson和jackson。
这边我们以jackson为例来说明。
1.）引入Jackson库
<dependency> <groupId>com.fasterxml.jackson.core</groupId> <artifactId>jackson-databind</artifactId> <version>2.13.0</version> </dependency>
2.）定义实体
注意这边实体属性一定要跟json数据字段key对应，否则会解析报错
@Data
class BlogData
{
private Integer code;
private String message;
private String traceId;
private Record data;
}
@Data
class Record
{
private List<SubList> list;
private Long total;
}
@Data
class SubList
{
String articleId;
String title;
String description;
String url;
Integer type;
String top;
String forcePlan;
Long viewCount;
Long commentCount;
String editUrl;
String postTime;
Long diggCount;
String formatTime;
Object picList;
Long collectCount;
}3.）解析json字符串
ObjectMapper mapper = new ObjectMapper();
String url = "https://blog.csdn.net/community/home-api/v1/get-business-list?page=1&size=5&businessType=blog&username=qq_16127313";
String resp = webClient.get().uri(url).acceptCharset(StandardCharsets.UTF_8).accept(MediaType.APPLICATION_JSON).retrieve().bodyToMono(String.class).block();
BlogData blogData = mapper.readValue(resp, BlogData.class);
log.info("blogData: {} ", blogData);
4.）运行结果
4. 过程分析
分析整个json数据解析过程，我们发现在实体定义步骤上，花费了我们太多精力和时间，而且一旦json数据key命名有变化或属性名命名不对应，便会打印类似下面的错误信息：
com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "collectCount" (class com.fly.test.restful.json.SubList), not marked as ignorable (15 known properties: "formatTime", "editUrl", "picList", "viewCount", "collectCount1", "postTime", "url", "commentCount", "articleId", "forcePlan", "top", "title", "type", "description", "diggCount"])
at [Source: (String)"{"code":200,"message":"success","traceId":"ce6fbb2f-72da-4a9c-9cf4-4e532a942210","data":{"list":[{"articleId":135244727,"title":"java lambda表达式训练题一","description":"Lambda 表达式，也可称为闭包，它是推动 Java 8 发布的最重要新特性。Lambda 允许把函数作为一个方法的参数（函数作为参数传递进方法中）。使用 Lambda 表达式可以使代码变的更加简洁紧凑。","url":"https://blog.csdn.net/qq_16127313/article/details/135244727","type":1,"top":false,"forcePlan":false,"viewCount":1081,"commentCount":0,"editUrl":"https://editor.csdn.net/md?articleId=135244727","postTime":"2023-12-27 18:07:30"[truncated 2457 chars]; line: 1, column: 645] (through reference chain: com.fly.test.restful.json.BlogData["data"]->com.fly.test.restful.json.Record["list"]->java.util.ArrayList[0]->com.fly.test.restful.json.SubList["collectCount"])
at com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException.from(UnrecognizedPropertyException.java:61)
at com.fasterxml.jackson.databind.DeserializationContext.handleUnknownProperty(DeserializationContext.java:840)
at com.fasterxml.jackson.databind.deser.std.StdDeserializer.handleUnknownProperty(StdDeserializer.java:1206)
at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownProperty(BeanDeserializerBase.java:1592)
at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.handleUnknownVanilla(BeanDeserializerBase.java:1570)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:294)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:151)
at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:286)
at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:245)
at com.fasterxml.jackson.databind.deser.std.CollectionDeserializer.deserialize(CollectionDeserializer.java:27)
at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:129)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:288)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:151)
at com.fasterxml.jackson.databind.deser.impl.MethodProperty.deserializeAndSet(MethodProperty.java:129)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:288)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:151)
at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4202)
at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3205)
at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3173)
at com.fly.test.restful.json.ParseJson.test2(ParseJson.java:57)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.platform.commons.util.ReflectionUtils.invokeMethod(ReflectionUtils.java:675)
at org.junit.jupiter.engine.execution.MethodInvocation.proceed(MethodInvocation.java:60)
at org.junit.jupiter.engine.execution.InvocationInterceptorChain$ValidatingInvocation.proceed(InvocationInterceptorChain.java:125)
at org.junit.jupiter.engine.extension.TimeoutExtension.intercept(TimeoutExtension.java:132)
at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestableMethod(TimeoutExtension.java:124)
at org.junit.jupiter.engine.extension.TimeoutExtension.interceptTestMethod(TimeoutExtension.java:74)
at org.junit.jupiter.engine.execution.ExecutableInvoker$ReflectiveInterceptorCall.lambda$ofVoidMethod$0(ExecutableInvoker.java:115)
at org.junit.jupiter.engine.execution.ExecutableInvoker.lambda$invoke$0(ExecutableInvoker.java:105)
at org.junit.jupiter.engine.execution.InvocationInterceptorChain$InterceptedInvocation.proceed(InvocationInterceptorChain.java:104)
at org.junit.jupiter.engine.execution.InvocationInterceptorChain.proceed(InvocationInterceptorChain.java:62)
at org.junit.jupiter.engine.execution.InvocationInterceptorChain.chainAndInvoke(InvocationInterceptorChain.java:43)
at org.junit.jupiter.engine.execution.InvocationInterceptorChain.invoke(InvocationInterceptorChain.java:35)
at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:104)
at org.junit.jupiter.engine.execution.ExecutableInvoker.invoke(ExecutableInvoker.java:98)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.lambda$invokeTestMethod$6(TestMethodTestDescriptor.java:202)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.invokeTestMethod(TestMethodTestDescriptor.java:198)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:135)
at org.junit.jupiter.engine.descriptor.TestMethodTestDescriptor.execute(TestMethodTestDescriptor.java:69)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:135)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:125)
at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:123)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80)
at java.util.ArrayList.forEach(ArrayList.java:1257)
at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:139)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:125)
at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:123)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80)
at java.util.ArrayList.forEach(ArrayList.java:1257)
at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.invokeAll(SameThreadHierarchicalTestExecutorService.java:38)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$5(NodeTestTask.java:139)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$7(NodeTestTask.java:125)
at org.junit.platform.engine.support.hierarchical.Node.around(Node.java:135)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.lambda$executeRecursively$8(NodeTestTask.java:123)
at org.junit.platform.engine.support.hierarchical.ThrowableCollector.execute(ThrowableCollector.java:73)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.executeRecursively(NodeTestTask.java:122)
at org.junit.platform.engine.support.hierarchical.NodeTestTask.execute(NodeTestTask.java:80)
at org.junit.platform.engine.support.hierarchical.SameThreadHierarchicalTestExecutorService.submit(SameThreadHierarchicalTestExecutorService.java:32)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestExecutor.execute(HierarchicalTestExecutor.java:57)
at org.junit.platform.engine.support.hierarchical.HierarchicalTestEngine.execute(HierarchicalTestEngine.java:51)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:229)
at org.junit.platform.launcher.core.DefaultLauncher.lambda$execute$6(DefaultLauncher.java:197)
at org.junit.platform.launcher.core.DefaultLauncher.withInterceptedStreams(DefaultLauncher.java:211)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:191)
at org.junit.platform.launcher.core.DefaultLauncher.execute(DefaultLauncher.java:137)
at org.eclipse.jdt.internal.junit5.runner.JUnit5TestReference.run(JUnit5TestReference.java:98)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:40)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:529)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:756)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:452)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:210)
三、具体实现二
在上面的实现中，通过分析得知，我们关注的信息只有url、viewCount这2个字段值，并不关心其他字段信息。
在java工程中JSON 字符串格式化输出 中我们已经实现了将json字符串格式化后输出，仔细观察输出信息，会发现简单数据对象（如key、value均为字符串、数字等类型数据）均在同一行，这样我们通过解析输出的行字符串信息，便能得到对应信息。
1. 核心代码
// 调用接口
String url = "https://blog.csdn.net/community/home-api/v1/get-business-list?page=1&size=5&businessType=blog&username=qq_16127313";
String resp = webClient.get().uri(url).acceptCharset(StandardCharsets.UTF_8).accept(MediaType.APPLICATION_JSON).retrieve().bodyToMono(String.class).block();
// 数据格式化-jackson格式化后会在:前后添加空格
String pretty = mapper.readTree(resp).toPrettyString();
List<String> lines = IOUtils.readLines(new StringReader(pretty));
// 获取url
List<String> urls = lines.stream().filter(line -> StringUtils.contains(line, "\"url\"")).map(n -> StringUtils.substringBetween(n, " : \"", "\",")).collect(Collectors.toList());
urls.stream().forEach(log::info);
// 获取viewCount
List<String> viewCounts = lines.stream().filter(line -> StringUtils.contains(line, "\"viewCount\"")).map(n -> StringUtils.substringBetween(n, " : ", ",")).collect(Collectors.toList());
viewCounts.stream().forEach(log::info);
2.运行结果
四、方案比较
| 目标 | 方案一 | 方案二 |
|---|---|---|
| 复杂度 | 复杂 | 简单 |
| 健壮性 | 稍不足，需保证实体属性与json key全部严格对应 | 健壮，只需保证获取数据key正确 |
五、源码传送
到此这篇关于java解析json复杂数据的方法详解的文章就介绍到这了,更多相关java解析json复杂数据内容请搜索脚本之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持脚本之家！