使用 jackson 解析 json 演示样例「建议收藏」

全栈程序员-站长 • 2022年2月7日下午5:00 • 未分类 • 阅读 55

大家好，又见面了，我是全栈君。

首先须要下载3个包，下载地址在Github FasterXML，这三个核心模块各自是：

Streaming (“jackson-core“) defines low-level streaming API, and includes JSON-specific implementations

Annotations (“jackson-annotations“) contains standard Jackson annotations

Databind (“jackson-databind“) implements data-binding (and object serialization) support on streaming package;

it depends both on streaming and annotations packages。

json文件：

<span style="font-family:SimHei;font-size:18px;">{
     "name":" vonzhou",
     "age":123,
     "isMan":true
}</span>

POJO类：

<span style="font-family:SimHei;font-size:18px;">package jackson.test;

import java.util.HashMap;
import java.util.Map;

import com.fasterxml.jackson.annotation.JsonProperty;

public class ExamplePOJO {
      @JsonProperty( "name")
      private String name;
     
      @JsonProperty( "age")
      private Integer age;
     
      @JsonProperty( "isMan")
      private Boolean isMan;
     
      private Map<String,Object> additionalProperties = new
                HashMap<String, Object>();
     
      @JsonProperty( "name")
      public String getName() {
            return name;
     }
      @JsonProperty( "name")
      public void setName(String name) {
            this. name = name;
     }
      @JsonProperty( "age")
      public Integer getAge() {
            return age;
     }
      @JsonProperty( "age")
      public void setAge(Integer age) {
            this. age = age;
     }
      @JsonProperty( "isMan")
      public Boolean getIsMan() {
            return isMan;
     }
      @JsonProperty( "isMan")
      public void setIsMan(Boolean isMan) {
            this. isMan = isMan;
     }

      public Map<String, Object> getAdditionalProperties() {
            return additionalProperties;
     }

      public void setAdditionalProperties(String name, Object obj) {
            this. additionalProperties.put(name, obj);
     }
     
      @Override
      public String toString() {
            return "ExamplePOJO{\n" +
                      "name :'" + name + "',\n" +
                      "age : " + age + ",\n" +
                      "isMan :" + isMan + ",\n" +
                      "additionalProperties : " + additionalProperties +
                      "\n}";
     }
     

}

</span>

解析json文件的类：

<span style="font-family:SimHei;font-size:18px;">package jackson.test;import java.io.File;import java.io.IOException;import com.fasterxml.jackson.core.JsonParseException;import com.fasterxml.jackson.databind.JsonMappingException;import com.fasterxml.jackson.databind.ObjectMapper;public class Driver {     public static void main(String[] args) {          ObjectMapper mapper = new ObjectMapper();          try {               ExamplePOJO bean = mapper.readValue(new File("test.json"),                                                                  ExamplePOJO.class);               System.out.println("name : " + bean.getName());               System.out.println("age : " + bean.getAge() );               System.out.println("isMan : " + bean.getIsMan() );               System.out.println("===================");               System.out.println(bean.toString());          } catch (JsonParseException e) {               e.printStackTrace();          }catch (JsonMappingException e){               e.printStackTrace();          }catch (IOException e){               e.printStackTrace();          }                  }}</span>

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