如果项目需求是从某些复杂的json里面取值进行计算,用jsonpath+IK(ik-expression)来处理十分方便,jsonpath用来取json里面的值然后用IK自带的函数进行计算,如果是特殊的计算那就自定义IK方法搞定,配置化很方便.
下面简单介绍下jsonpath的使用方法,主要测试都在JsonPathDemo类里面:
下面是一个简单的java项目demo:
注意: 其中他的max,min,avg,stddev函数只能类似于如下处理:
//正确写法 但是感觉很鸡肋context.read("$.avg($.result.records[0].loan_type,$.result.records[1].loan_type,$.result.records[2].loan_type)");
不能传入list 感觉比较鸡肋,如果传入list 他会报错(如下错误写法):
//这样会报错Object maxV = context.read("$.max($.result.records[*].loan_type)");//这样也会报错Object maxV = context.read("$.result.records[*].loan_type.max()");//如果json文件中是这样:"loan_type":"2",也会报错,"loan_type":2 这样才被认为是数字
报错信息都一样, 如下:
Exception in thread “main” com.jayway.jsonpath.JsonPathException: Aggregation function attempted to calculate value using empty array
JsonPathDemo是一个测试demo:
public class JsonPathDemo { public static void main(String[] args) { String json = FileUtils.readFileByLines("demo.json"); ReadContext context = JsonPath.parse(json); //1 返回所有name List<String> names = context.read("$.result.records[*].name"); //["张三","李四","王五"] System.out.println(names); //2 返回所有数组的值 List<Map<String, String>> objs = context.read("$.result.records[*]"); //[{"name":"张三","pid":"500234199212121212","mobile":"18623456789","applied_at":"3","confirmed_at":"5","confirm_type":"overdue","loan_type":"1","test":"mytest","all":"2"},{"name":"李四","pid":"500234199299999999","mobile":"13098765432","applied_at":"1","confirmed_at":"","confirm_type":"overdue","loan_type":"3","all":"3"},{"name":"王五","pid":"50023415464654659","mobile":"1706454894","applied_at":"-1","confirmed_at":"","confirm_type":"overdue","loan_type":"3"}] System.out.println(objs); //3 返回第一个的name String name0 = context.read("$.result.records[0].name"); //张三 System.out.println(name0); //4 返回下标为0 和 2 的数组值 List<String> name0and2 = context.read("$.result.records[0,2].name"); //["张三","王五"] System.out.println(name0and2); //5 返回下标为0 到 下标为1的 的数组值 这里[0:2] 表示包含0 但是 不包含2 List<String> name0to2 = context.read("$.result.records[0:2].name"); //["张三","李四"] System.out.println(name0to2); //6 返回数组的最后两个值 List<String> lastTwoName = context.read("$.result.records[-2:].name"); //["李四","王五"] System.out.println(lastTwoName); //7 返回下标为1之后的所有数组值 包含下标为1的 List<String> nameFromOne = context.read("$.result.records[1:].name"); //["李四","王五"] System.out.println(nameFromOne); //8 返回下标为3之前的所有数组值 不包含下标为3的 List<String> nameEndTwo = context.read("$.result.records[:3].name"); //["张三","李四","王五"] System.out.println(nameEndTwo); //9 返回applied_at大于等于2的值 List<Map<String, String>> records = context.read("$.result.records[?(@.applied_at >= '2')]"); //[{"name":"张三","pid":"500234199212121212","mobile":"18623456789","applied_at":"3","confirmed_at":"5","confirm_type":"overdue","loan_type":"1","test":"mytest","all":"2"}] System.out.println(records); //10 返回name等于李四的值 List<Map<String, String>> records0 = context.read("$.result.records[?(@.name == '李四')]"); //[{"name":"李四","pid":"500234199299999999","mobile":"13098765432","applied_at":"1","confirmed_at":"","confirm_type":"overdue","loan_type":"3"}] System.out.println(records0); //11 返回有test属性的数组 List<Map<String, String>> records1 = context.read("$.result.records[?(@.test)]"); //[{"name":"张三","pid":"500234199212121212","mobile":"18623456789","applied_at":"3","confirmed_at":"5","confirm_type":"overdue","loan_type":"1","test":"mytest","all":"2"}] System.out.println(records1); //12 返回有test属性的数组 List<String> list = context.read("$..all"); //["1","4","2","3"] System.out.println(list); //12 以当前json的某个值为条件查询 这里ok为1 取出records数组中applied_at等于1的数组 List<String> ok = context.read("$.result.records[?(@.applied_at == $['ok'])]"); //["1","4","2","3"] System.out.println(ok); //13 正则匹配 List<String> regexName = context.read("$.result.records[?(@.pid =~ /.*999/i)]"); //[{"name":"李四","pid":"500234199299999999","mobile":"13098765432","applied_at":"1","confirmed_at":"","confirm_type":"overdue","loan_type":"3","all":"3"}] System.out.println(regexName); //14 多条件 List<String> mobile = context.read("$.result.records[?(@.all == '2' || @.name == '李四' )].mobile"); //["18623456789","13098765432"] System.out.println(mobile); //14 查询数组长度 Integer length01 = context.read("$.result.records.length()"); //3 System.out.println(length01); //15 查询list里面每个对象长度 List<Integer> length02 = context.read("$.result.records[?(@.all == '2' || @.name == '李四' )].length()"); //[9,8] System.out.println(length02); //16 最大值 Object maxV = context.read("$.max($.result.records[0].loan_type,$.result.records[1].loan_type,$.result.records[2].loan_type)"); //3.0 System.out.println(maxV); //17 最小值 Object minV = context.read("$.min($.result.records[0].loan_type,$.result.records[1].loan_type,$.result.records[2].loan_type)"); //1.0 System.out.println(minV); //18 平均值 double avgV = context.read("$.avg($.result.records[0].loan_type,$.result.records[1].loan_type,$.result.records[2].loan_type)"); //2.3333333333333335 System.out.println(avgV); //19 标准差 double stddevV = context.read("$.stddev($.result.records[0].loan_type,$.result.records[1].loan_type,$.result.records[2].loan_type)"); //0.9428090415820636 System.out.println(stddevV); //20 读取一个不存在的 String haha = context.read("$.result.haha"); //抛出异常 //Exception in thread "main" com.jayway.jsonpath.PathNotFoundException: No results for path: $['result']['haha'] //at com.jayway.jsonpath.internal.path.EvaluationContextImpl.getValue(EvaluationContextImpl.java:133) //at com.jayway.jsonpath.JsonPath.read(JsonPath.java:187) //at com.jayway.jsonpath.internal.JsonContext.read(JsonContext.java:102) //at com.jayway.jsonpath.internal.JsonContext.read(JsonContext.java:89) //at cn.lijie.jsonpath.JsonPathDemo.main(JsonPathDemo.java:58) //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 com.intellij.rt.execution.application.AppMain.main(AppMain.java:147) System.out.println(haha); }}
pom文件引入:
<dependency> <groupId>com.jayway.jsonpath</groupId> <artifactId>json-path</artifactId> <version>2.3.0</version> </dependency>
其中demo.json是一个测试json:
{ "action": "/interface.service/xxx/queryBlackUserData", "all": "1", "result": { "count": 2, "tenant_count": 2, "records": [ { "name": "张三", "pid": "500234199212121212", "mobile": "18623456789", "applied_at": "3", "confirmed_at": "5", "confirm_type": "overdue", "loan_type": 1, "test": "mytest", "all": "2" }, { "name": "李四", "pid": "500234199299999999", "mobile": "13098765432", "applied_at": "1", "confirmed_at": "", "confirm_type": "overdue", "loan_type": 3, "all": "3" }, { "name": "王五", "pid": "50023415464654659", "mobile": "1706454894", "applied_at": "-1", "confirmed_at": "", "confirm_type": "overdue", "loan_type": 3 } ], "all": "4" }, "code": 200, "subtime": "1480495123550", "status": "success", "ok": 3}
FileUtils类是用于读取xx.json文件为字符串的json:
public class FileUtils { /** * 以行为单位读取文件，常用于读面向行的格式化文件 */ public static String readFileByLines(String fileName) { File file = new File(fileName); BufferedReader reader = null; String str = ""; try { InputStream is = FileUtils.class.getClassLoader().getResourceAsStream(fileName); reader = new BufferedReader(new InputStreamReader(is)); String tempString = null; int line = 1; // 一次读入一行，直到读入null为文件结束 while ((tempString = reader.readLine()) != null) { // 显示行号 str += tempString; } reader.close(); } catch (IOException e) { e.printStackTrace(); } finally { if (reader != null) { try { reader.close(); } catch (IOException e1) { } } } return str; }}
补充：json接口测试的利器jsonpath
在测试REST接口的时候，经常要解析JSON，那么可以使用开源jsonpath进行，其中看网上看到相关的说法不错的使用场景为：
1、接口关联
也称为关联参数。在应用业务接口中，完成一个业务功能时，有时候一个接口可能不满足业务的整个流程逻辑，需要多个接口配合使用，简单的案例如：B接口的成功调用依赖于A接口，需要在A接口的响应数据（response)中拿到需要的字段，在调用B接口的时候，传递给B接口作为B接口请求参数，拿到后续响应的响应数据。
接口关联通常可以使用正则表达式去提取需要的数据，但对于json这种简洁、清晰层次结构、轻量级的数据交互格式，使用正则未免有点杀鸡用牛刀的感觉(是的，因为我不擅长写正则表达式)，我们需要更加简单、直接的提取json数据的方式。
2、数据验证
这里的数据验证指的是对响应结果进行数据的校验
接口自动化测试中，对于简单的响应结果（json），可以直接和期望结果进行比对，判断是否完全相等即可。
如 json {“status”:1,”msg”:”登录成功”}
3、对于格式较复杂
尤其部分数据存在不确定性、会根据实际情况变化的响应结果，简单的判断是否完全相等（断言）通常会失败。
如：
json {"status":1,"code":"10001","data":[{"id":1,"investId":"1","createTime":"2018-04-27 12:24:01","terms":"1","unfinishedInterest":"1.0","unfinishedPrincipal":"0","repaymentDate":"2018-05-27 12:24:01","actualRepaymentDate":null,"status":"0"},{"id":2,"investId":"1","createTime":"2018-04-27 12:24:01","terms":"2","unfinishedInterest":"1.0","unfinishedPrincipal":"0","repaymentDate":"2018-06-27 12:24:01","actualRepaymentDate":null,"status":"0"},{"id":3,"investId":"1","createTime":"2018-04-27 12:24:01","terms":"3","unfinishedInterest":"1.0","unfinishedPrincipal":"100.00","repaymentDate":"2018-07-27 12:24:01","actualRepaymentDate":null,"status":"0"}],"msg":"获取信息成功"}
上面的json结构嵌套了很多信息，完整的匹配几乎不可能成功。比如其中的createTime信息，根据执行接口测试用例的时间每次都不一样。同时这个时间是响应结果中较为次要的信息，在进行接口自动化测试时，是可以选择被忽略的。
4、我们需要某种简单的方法
能够从json中提取出我们真正关注的信息（通常也被称为关键信息）。
如提取出status的值为1，data数组中每个对象的investId都为1，data中第三个对象的unfinishedPrincipal值为100.00，只要这三个关键信息校验通过，我们就认为响应结果没有问题。
JSONPATH有点像XPATH了，语法规则小结下：
这里有个表格，说明JSONPath语法元素和对应XPath元素的对比。
XPath JSONPath Description / $ 表示根元素 . @ 当前元素 / . or [] 子元素 .. n/a 父元素 // .. 递归下降，JSONPath是从E4X借鉴的。 * * 通配符，表示所有的元素 @ n/a 属性访问字符 [] []子元素操作符
| [,]
连接操作符在XPath 结果合并其它结点集合。JSONP允许name或者数组索引。
n/a [start:end:step]
数组分割操作从ES4借鉴。
[] ?()
应用过滤表示式
n/a ()
脚本表达式，使用在脚本引擎下面。
() n/a Xpath分组
下面是一个简单的json数据结构代表一个书店（原始的xml文件是）
{ "store": { "book": [ { "category": "reference", "author": "Nigel Rees", "title": "Sayings of the Century", "price": 8.95 }, { "category": "fiction", "author": "Evelyn Waugh", "title": "Sword of Honour", "price": 12.99 }, { "category": "fiction", "author": "Herman Melville", "title": "Moby Dick", "isbn": "0-553-21311-3", "price": 8.99 }, { "category": "fiction", "author": "J. R. R. Tolkien", "title": "The Lord of the Rings", "isbn": "0-395-19395-8", "price": 22.99 } ], "bicycle": { "color": "red", "price": 19.95 } }}
XPath JSONPath 结果 /store/book/author $.store.book[*].author
书点所有书的作者
//author $..author
所有的作者
/store/* $.store.*
store的所有元素。所有的bookst和bicycle
/store//price $.store..price
store里面所有东西的price
//book[3] $..book[2]
第三个书
//book[last()] $..book[(@.length-1)] 最后一本书 //book[position()<3] $..book[0,1]
$..book[:2]
前面的两本书。 //book[isbn] $..book[?(@.isbn)] 过滤出所有的包含isbn的书。 //book[price<10] $..book[?(@.price<10)] 过滤出价格低于10的书。 //* $..*
所有元素。
比如在单元测试MOCK中，就可以这样使用：
@RunWith(SpringRunner.class)@SpringBootTest@AutoConfigureMockMvc@ActiveProfiles("test")public class BookControllerTest { @Autowired private MockMvc mockMvc; @MockBean private BookRepository mockRepository; /* { "timestamp":"2019-03-05T09:34:13.280+0000", "status":400, "errors":["Author is not allowed.","Please provide a price","Please provide a author"] } */ //article : jsonpath in array @Test public void save_emptyAuthor_emptyPrice_400() throws Exception { String bookInJson = "{\"name\":\"ABC\"}"; mockMvc.perform(post("/books") .content(bookInJson) .header(HttpHeaders.CONTENT_TYPE, MediaType.APPLICATION_JSON)) .andDo(print()) .andExpect(status().isBadRequest()) .andExpect(jsonPath("$.timestamp", is(notNullValue()))) .andExpect(jsonPath("$.status", is(400))) .andExpect(jsonPath("$.errors").isArray()) .andExpect(jsonPath("$.errors", hasSize(3))) .andExpect(jsonPath("$.errors", hasItem("Author is not allowed."))) .andExpect(jsonPath("$.errors", hasItem("Please provide a author"))) .andExpect(jsonPath("$.errors", hasItem("Please provide a price"))); verify(mockRepository, times(0)).save(any(Book.class)); }}
以上为个人经验，希望能给大家一个参考，也希望大家多多支持。如有错误或未考虑完全的地方，望不吝赐教。
会让你的心态更平和更坦然，
