java Json/xml/properties file processing

Article Directory

1. json file processing
- 1.1 Use gson to read and parse json configuration files
- 1.2 Jackson converts Java objects into json string
2. Parsing properties files

1. json file processing

json string formatting can be viewed using the jsonviewer tool. Sometimes, when writing a json string, it is easy to miss one or other paired symbols. This tool can check whether the string conforms to the josn format. And the tools are relatively small

Java processing includes the following methods:

type	Introduction
Traditional Json method	There are defects in converting complex Json data into entity classes, and their performance and functions are not perfect.
Jackson way	There are flaws in converting complex Json data into entity classes, and its performance and functionality are better than traditional methods
Gson way	Functionality is the best among several methods, but performance is not as good as Jackson's method
FastJson way	There are flaws in converting complex entity classes into Json data, and parsing json is better than other methods

The following mainly introduces gson and jackson

1.1 Use gson to read and parse json configuration files

Using gson requires importing packages. Using gson to read and parse json is simpler.

Basic steps:

Define a simple java object, which needs to be basically consistent with the json hierarchy and the json string.

class  Configuration{
int initDelay;
String type
ArrayList <Metrics > metricsList;
}
class Metrics{
.....
}

Get the json string from a file or elsewhere (stored into a String dataString variable), parsing:

gson gson=new Gson();
Configuration config=(dataString,);

1.2 Jackson converts Java objects into json string

Directly use jackson to serialize java classes into strings

 ObjectMapper mapper = new ObjectMapper();
 String json = (config);

Common annotations:

Annotation name	effect
@JsonIgnore	This annotation is used on attributes, and the function is to ignore this attribute when performing JSON operations.
@JsonFormat	This annotation is used for attributes, and its function is to directly convert the Date type into the desired format, such as @JsonFormat(pattern = "yyyy-MM-dd HH-mm-ss").
@JsonProperty	By default, the mapped JSON attribute is the same as the annotated attribute name. This annotation is used for attributes, and the function is to serialize the name of the attribute to another name, such as serializing the trueName attribute to name, @JsonProperty("name").

2. Analysispropertiesdocument

Directly use java's Properties class to handle it
Basic processing code:

String fileName=""
 Properties prop = new Properties();
 try( InputStream stream = new BufferedInputStream(new FileInputStream(fileName){
   (stream);
 }catch(Exception e){
   return false;
 }
 Iterator<String> it=().iterator();
 while(()){
     // Process each key
     ....
 }