JsonPath提供的json解析非常強大,它提供了類似正則表達式的語法,基本上可以滿足所有你想要獲得的json內容。下面我把官網介紹的每個表達式用代碼實現,可以更直觀的知道該怎麼用它。
一.首先需要依賴的jar包
二.因爲編譯的時候會報log4j的警報,所以需要在項目的src目錄下新建log4j.properties文件,內容如下:
log4j.rootLogger=WARN, stdout
log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - %m%n
三,用下面的json例子來做數據
{
"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
}
},
"expensive": 10
}
四 。Java代碼如下
package com.jsonpath;
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import net.minidev.json.JSONArray;
import com.jayway.jsonpath.Configuration;
import com.jayway.jsonpath.JsonPath;
import com.jayway.jsonpath.ReadContext;
/**
* @author QiaoJiafei
* @version 創建時間:2016年3月2日 下午3:37:42
* 類說明
*/
public class TestJsonPath {
public static void main(String[] args) {
// TODO Auto-generated method stub
String sjson = readtxt();
//String sjson = "{\"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}},\"expensive\": 10}";
/*
print("--------------------------------------getJsonValue0--------------------------------------");
getJsonValue0(sjson);
print("--------------------------------------getJsonValue1--------------------------------------");
getJsonValue1(sjson);
print("--------------------------------------getJsonValue2--------------------------------------");
getJsonValue2(sjson);
print("--------------------------------------getJsonValue3--------------------------------------");
getJsonValue3(sjson);
print("--------------------------------------getJsonValue4--------------------------------------");
getJsonValue4(sjson);
*/
print("--------------------------------------getJsonValue--------------------------------------");
getJsonValue(sjson);
}
private static String readtxt() {
// TODO Auto-generated method stub
StringBuilder sb = new StringBuilder();
try {
FileReader fr = new FileReader("D:/workspace/PressureTest/json.txt");
BufferedReader bfd = new BufferedReader(fr);
String s = "";
while((s=bfd.readLine())!=null) {
sb.append(s);
}
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println(sb.toString());
return sb.toString();
}
private static void getJsonValue(String json) {
//The authors of all books:獲取json中store下book下的所有author值
List<String> authors1 = JsonPath.read(json, "$.store.book[*].author");
//All authors:獲取所有json中所有author的值
List<String> authors2 = JsonPath.read(json, "$..author");
//All things, both books and bicycles //authors3返回的是net.minidev.json.JSONArray:獲取json中store下的所有value值,不包含key,如key有兩個,book和bicycle
List<Object> authors3 = JsonPath.read(json, "$.store.*");
//The price of everything:獲取json中store下所有price的值
List<Object> authors4 = JsonPath.read(json, "$.store..price");
//The third book:獲取json中book數組的第3個值
List<Object> authors5 = JsonPath.read(json, "$..book[2]");
//The first two books:獲取json中book數組的第1和第2兩個個值
List<Object> authors6 = JsonPath.read(json, "$..book[0,1]");
//All books from index 0 (inclusive) until index 2 (exclusive):獲取json中book數組的前兩個區間值
List<Object> authors7 = JsonPath.read(json, "$..book[:2]");
//All books from index 1 (inclusive) until index 2 (exclusive):獲取json中book數組的第2個值
List<Object> authors8 = JsonPath.read(json, "$..book[1:2]");
//Last two books:獲取json中book數組的最後兩個值
List<Object> authors9 = JsonPath.read(json, "$..book[-2:]");
//Book number two from tail:獲取json中book數組的第3個到最後一個的區間值
List<Object> authors10 = JsonPath.read(json, "$..book[2:]");
//All books with an ISBN number:獲取json中book數組中包含isbn的所有值
List<Object> authors11 = JsonPath.read(json, "$..book[?(@.isbn)]");
//All books in store cheaper than 10:獲取json中book數組中price<10的所有值
List<Object> authors12 = JsonPath.read(json, "$.store.book[?(@.price < 10)]");
//All books in store that are not "expensive":獲取json中book數組中price<=expensive的所有值
List<Object> authors13 = JsonPath.read(json, "$..book[?(@.price <= $['expensive'])]");
//All books matching regex (ignore case):獲取json中book數組中的作者以REES結尾的所有值(REES不區分大小寫)
List<Object> authors14 = JsonPath.read(json, "$..book[?(@.author =~ /.*REES/i)]");
//Give me every thing:逐層列出json中的所有值,層級由外到內
List<Object> authors15 = JsonPath.read(json, "$..*");
//The number of books:獲取json中book數組的長度
List<Object> authors16 = JsonPath.read(json, "$..book.length()");
print("**************authors1**************");
print(authors1);
print("**************authors2**************");
print(authors2);
print("**************authors3**************");
printOb(authors3);
print("**************authors4**************");
printOb(authors4);
print("**************authors5**************");
printOb(authors5);
print("**************authors6**************");
printOb(authors6);
print("**************authors7**************");
printOb(authors7);
print("**************authors8**************");
printOb(authors8);
print("**************authors9**************");
printOb(authors9);
print("**************authors10**************");
printOb(authors10);
print("**************authors11**************");
printOb(authors11);
print("**************authors12**************");
printOb(authors12);
print("**************authors13**************");
printOb(authors13);
print("**************authors14**************");
printOb(authors14);
print("**************authors15**************");
printOb(authors15);
print("**************authors16**************");
printOb(authors16);
}
/**
* 讀取json的一種寫法,得到匹配表達式的所有值
* */
private static void getJsonValue0(String json) {
// TODO Auto-generated method stub
List<String> authors = JsonPath.read(json, "$.store.book[*].author");
//System.out.println(authors.size());
print(authors);
}
/**
* 讀取json的一種寫法,得到某個具體值
* */
private static void getJsonValue1(String json) {
Object document = Configuration.defaultConfiguration().jsonProvider().parse(json);
String author0 = JsonPath.read(document, "$.store.book[0].author");
String author1 = JsonPath.read(document, "$.store.book[1].author");
print(author0);
print(author1);
}
/**
* 讀取json的一種寫法
* */
private static void getJsonValue2(String json) {
ReadContext ctx = JsonPath.parse(json);
List<String> authorsOfBooksWithISBN = ctx.read("$.store.book[?(@.isbn)].author");
List<Map<String, Object>> expensiveBooks = JsonPath
.using(Configuration.defaultConfiguration())
.parse(json)
.read("$.store.book[?(@.price > 10)]", List.class);
print(authorsOfBooksWithISBN);
print("****************Map****************");
printListMap(expensiveBooks);
}
/**
*讀取json的一種寫法
*得到的值是一個String,所以不能用List存儲
* */
private static void getJsonValue3(String json) {
//Will throw an java.lang.ClassCastException
//List<String> list = JsonPath.parse(json).read("$.store.book[0].author");
//由於會拋異常,暫時註釋上面一行,要用的話,應使用下面的格式
//Works fine
String author = JsonPath.parse(json).read("$.store.book[0].author");
print(author);
}
/**
*讀取json的一種寫法
*支持邏輯表達式,&&和||
* */
private static void getJsonValue4(String json) {
List<Map<String, Object>> books1 = JsonPath.parse(json)
.read("$.store.book[?(@.price < 10 && @.category == 'fiction')]");
List<Map<String, Object>> books2 = JsonPath.parse(json)
.read("$.store.book[?(@.category == 'reference' || @.price > 10)]");
print("****************books1****************");
printListMap(books1);
print("****************books2****************");
printListMap(books1);
}
private static void print(List<String> list) {
for(Iterator<String> it = list.iterator();it.hasNext();) {
System.out.println(it.next());
}
}
private static void printOb(List<Object> list) {
for(Iterator<Object> it = list.iterator();it.hasNext();) {
print("****");
System.out.println(it.next());
}
}
private static void printListMap(List<Map<String, Object>> list) {
for(Iterator<Map<String, Object>> it = list.iterator();it.hasNext();) {
Map<String, Object> map = it.next();
print("****");
for(Iterator iterator =map.entrySet().iterator();iterator.hasNext();) {
System.out.println(iterator.next());
}
}
}
private static void print(String s) {
System.out.println(s);
}
}
結果
首先我們看getJsonValue()這個方法的輸出結果:
--------------------------------------getJsonValue--------------------------------------
**************authors1**************
Nigel Rees
Evelyn Waugh
Herman Melville
J. R. R. Tolkien
**************authors2**************
Nigel Rees
Evelyn Waugh
Herman Melville
J. R. R. Tolkien
**************authors3**************
[{"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}]
{color=red, price=19.95}
**************authors4**************
8.95
12.99
8.99
22.99
19.95
**************authors5**************
{category=fiction, author=Herman Melville, title=Moby Dick, isbn=0-553-21311-3, price=8.99}
**************authors6**************
{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}
**************authors7**************
{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}
**************authors8**************
{category=fiction, author=Evelyn Waugh, title=Sword of Honour, price=12.99}
**************authors9**************
{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}
**************authors10**************
{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}
**************authors11**************
{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}
**************authors12**************
{category=reference, author=Nigel Rees, title=Sayings of the Century, price=8.95}
{category=fiction, author=Herman Melville, title=Moby Dick, isbn=0-553-21311-3, price=8.99}
**************authors13**************
{category=reference, author=Nigel Rees, title=Sayings of the Century, price=8.95}
{category=fiction, author=Herman Melville, title=Moby Dick, isbn=0-553-21311-3, price=8.99}
**************authors14**************
{category=reference, author=Nigel Rees, title=Sayings of the Century, price=8.95}
**************authors15**************
{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}}
[{"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}]
{color=red, price=19.95}
{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}
reference
Nigel Rees
Sayings of the Century
8.95
fiction
Evelyn Waugh
Sword of Honour
12.99
fiction
Herman Melville
Moby Dick
0-553-21311-3
8.99
fiction
J. R. R. Tolkien
The Lord of the Rings
0-395-19395-8
22.99
red
19.95
**************authors16**************
2.然後看getJsonValue0()、getJsonValue1()、getJsonValue2()、getJsonValue3()、getJsonValue4()的輸出結果
--------------------------------------getJsonValue0--------------------------------------
Nigel Rees
Evelyn Waugh
Herman Melville
J. R. R. Tolkien
--------------------------------------getJsonValue1--------------------------------------
Nigel Rees
Evelyn Waugh
--------------------------------------getJsonValue2--------------------------------------
Herman Melville
J. R. R. Tolkien
****************Map****************
****
category=fiction
author=Evelyn Waugh
title=Sword of Honour
price=12.99
****
category=fiction
author=J. R. R. Tolkien
title=The Lord of the Rings
isbn=0-395-19395-8
price=22.99
--------------------------------------getJsonValue3--------------------------------------
Nigel Rees
--------------------------------------getJsonValue4--------------------------------------
****************books1****************
****
category=fiction
author=Herman Melville
title=Moby Dick
isbn=0-553-21311-3
price=8.99
****************books2****************
****
category=fiction
author=Herman Melville
title=Moby Dick
isbn=0-553-21311-3
price=8.99
3.相應的解釋已經在代碼中註釋,更多的用法詳見官網鏈接:https://github.com/jayway/JsonPath
4.如果只是想簡單的處理json,也可以使用JSONObject和JSONArray,具體用法詳見這篇文章:http://www.cnblogs.com/qiaoyeye/p/4730930.html
原文轉:https://www.cnblogs.com/qiaoyeye/p/5236103.html