java json 接口 java jsonpath

记录下几种常用用法：

添加依赖：
com.jayway.jsonpath
json-path
2.4.0
测试如下：
/**
* TestJsonPath 各种类型测试
*/
@Test
public void TestJsonPath() {
String JsonString = "{\n" +
" \"store\": {\n" +
" \"book\": [\n" +
" {\n" +
" \"category\": \"reference\",\n" +
" \"author\": \"Nigel Rees\",\n" +
" \"title\": \"Sayings of the Century\",\n" +
" \"price\": 8.95\n" +
" },\n" +
" {\n" +
" \"category\": \"fiction\",\n" +
" \"author\": \"Evelyn Waugh\",\n" +
" \"title\": \"Sword of Honour\",\n" +
" \"price\": 12.99\n" +
" },\n" +
" {\n" +
" \"category\": \"fiction\",\n" +
" \"author\": \"Herman Melville\",\n" +
" \"title\": \"Moby Dick\",\n" +
" \"isbn\": \"0-553-21311-3\",\n" +
" \"price\": 8.99\n" +
" },\n" +
" {\n" +
" \"category\": \"fiction\",\n" +
" \"author\": \"J. R. R. Tolkien\",\n" +
" \"title\": \"The Lord of the Rings\",\n" +
" \"isbn\": \"0-395-19395-8\",\n" +
" \"price\": 22.99\n" +
" }\n" +
" ],\n" +
" \"bicycle\": {\n" +
" \"color\": \"red\",\n" +
" \"price\": 19.95\n" +
" }\n" +
" },\n" +
" \"expensive\": \"10\"\n" +
"}" ;
// 输出 所有 book 对象
String jsonPath = "$.store.book.[*]";
List msg = JsonPath.read(JsonString, jsonPath);
System.out.println(msg.toString());
//[{"category":"reference","author":"Nigel Rees","title":"Sayings of the Century","price":8.95},{"category":"fiction","author":"Evelyn Waugh","title":"Sword of Honour","price":12.99},{"category":"fiction","author":"Herman Melville","title":"Moby Dick","isbn":"0-553-21311-3","price":8.99},{"category":"fiction","author":"J. R. R. Tolkien","title":"The Lord of the Rings","isbn":"0-395-19395-8","price":22.99}]
//输出 所有 author 字段
jsonPath = "$.store.book[*].author";
List readMsg = JsonPath.read(JsonString, jsonPath);
System.out.println(readMsg.toString());
//["Nigel Rees","Evelyn Waugh","Herman Melville","J. R. R. Tolkien"]
//输出的 集合不存在 不会空指针 List = []
jsonPath = "$.store.book[*].author111";
List readMsg1 = JsonPath.read(JsonString, jsonPath);
System.out.println(readMsg1.toString());
// []
// 输出 单个字段 接受需要指定类型
jsonPath = "$.expensive";
String readMsg2 = JsonPath.read(JsonString, jsonPath);
System.out.println(readMsg2);
// 10
// 取出list 用LinkedHashMap 接收
String jsonPath4 = "$.store.book";
List msg4 = JsonPath.read(JsonString, jsonPath4);
System.out.println(msg4.toString());
// List 转换 jsonArray
JSONArray myResult = new JSONArray();
for (LinkedHashMap linkedHashMap :msg4) {
JSONObject jSONObject = new JSONObject();
Iterator it = linkedHashMap.entrySet().iterator();
while (it.hasNext()) {
Map.Entry entry = (Map.Entry) it.next();
jSONObject.put((String) entry.getKey(), entry.getValue());
}
myResult.put(jSONObject);
}
System.out.println(myResult);
//修改 某个字段值
DocumentContext doc = JsonPath.parse(JsonString).set("$.store.book.[2].author", "Jayway");
System.out.println(doc.read("$.store.book.[1].author").toString());
System.out.println(doc.read("$.store.book.[2].author").toString());
//修改全部
doc = JsonPath.parse(JsonString).set("$.store.book.[*].author", "Jayway");
System.out.println(doc.read("$.store.book.[*].author").toString());
//DocumentContext 转string
String docString = doc.jsonString();
System.out.println(docString);
}