java知识 特殊符号转换

Posted 2020-10-03 Mr.袋鼠

■情况

想把代码中的出现  “  ’等特殊符号时，在他们的前面，转换时自动加 \    最后转换成json

决定用ObjectMapper这个类，先准备一个Map，之后，map作为一个参数，调用ObjectMapper的方法，就能在转换时自动加上 \ 

■代码

 1 import java.io.IOException;
 2 import java.util.HashMap;
 3 import java.util.Map;
 4 
 5 import com.fasterxml.jackson.core.JsonParseException;
 6 import com.fasterxml.jackson.core.type.TypeReference;
 7 import com.fasterxml.jackson.databind.JsonMappingException;
 8 import com.fasterxml.jackson.databind.ObjectMapper;
 9 import com.fasterxml.jackson.databind.SerializationFeature;
10 
11 public class ObjectMapperDemo {
12 
13     public static void main(String args[]) throws JsonParseException, JsonMappingException, IOException {
14         ObjectMapper objectMapper = new ObjectMapper();
15         //Set pretty printing of json
16         objectMapper.enable(SerializationFeature.INDENT_OUTPUT);
17 
18         //Define map which will be converted to JSON
19         Map<String, String>mapIdPerson  = new HashMap<String, String>();
20         mapIdPerson.put("id", "001");
21         mapIdPerson.put("name", "James");
22         mapIdPerson.put("age", "13");
23         mapIdPerson.put("address", "street \"18");
24         
25         //1. Convert Map to JSON
26         String mapToJson = objectMapper.writeValueAsString(mapIdPerson);
27         System.out.println("1. Convert Map to JSON :");
28         System.out.println(mapToJson);
29         
30         //2. JSON to Map
31         //Define Custom Type reference for map type
32         TypeReference<Map<String, String>> mapType = new TypeReference<Map<String,String>>() {};
33         Map<String,String> jsonToMap = objectMapper.readValue(mapToJson, mapType);
34         System.out.println("\n2. Convert JSON to Map :");
35         
36         // Print map output using Java 8
37         // lambda expressions
38         jsonToMap.forEach((k, v) -> 
39                             System.out.println(k + "=" + v));
40     }
41 }

■运行结果

 1 1. Convert Map to JSON :
 2 {
 3   "address" : "street \"18",
 4   "name" : "James",
 5   "id" : "001",
 6   "age" : "13"
 7 }
 8 
 9 2. Convert JSON to Map :
10 address=street "18
11 name=James
12 id=001
13 age=13

 

maven的链接如下，你可以选择自己想要的jar包版本：

https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind