使用 Gson 从 json 创建类

Question

我正在使用：

Gson gson = new Gson();
return gson.fromJson(jsonstr,cls);

jsonstr 在哪里：

{"title": "ttl","data": "dta"}

而 cls 是：

public class GSONTest {

public String title;
public String data;

public String getTitle() {
    return title;
}

public String getData() {
    return data;
}

}

但我会做一些更复杂的事情，这是我的 json 示例：

{
  "Some1": {
    "data": "dta",
    "title": "ttl"
  },
  "Some3": {
    "data": "dta2",
    "title": "ttl2"
  }
}

对于这种类型的 json，我的班级应该是什么样子？

Answer 1

    Type type = new TypeToken<Map<String, GSONTest>>(){}.getType();
    Map<String, GSONTest> gsonTestMap = gson.fromJson(jsonstr, type);

Answer 2

正如您所见，每个 JSON 对象都类似于 java 中的一个类，因此您应该为 JSON 的根创建一个 Java 类，如下所示：

public class GSONTest {

    GSONTest2 element1;
    GSONTest2 element2;

    //constructor, getters and setters here

}

你看到我使用了另一个对象，所以它可以存储你的 JSON 的“level2”这个类将是这样的：

public class GSONTest2{
    String element1; //This will stored "dta and dta2"
    String element2; //This will stored "ttl1 and ttl2"
    //constructor, getters and setters here 

}

因此，当您调用 GSON 时，您应该这样做：

Gson gson = new Gson();
return gson.fromJson(jsonstr,GSONTest.class);

Answer 3

示例 {

 @SerializedName("Some1")
 @Expose
 private Some1 some1;
 @SerializedName("Some3")
 @Expose
 private Some3 some3;


 public Some1 getSome1() {
  return some1;
 }

 public void setSome1(Some1 some1) {
  this.some1 = some1;
 }


 public Some3 getSome3() {
  return some3;
 }


 public void setSome3(Some3 some3) {
  this.some3 = some3;
 }

}

------------------------com.example.Some1.java----- ------------

 import com.google.gson.annotations.Expose;
 import com.google.gson.annotations.SerializedName;

 public class Some1 {

  @SerializedName("data")
  @Expose
  private String data;
  @SerializedName("title")
  @Expose
  private String title;

 public String getData() {
   return data;
 }


 public void setData(String data) {
  this.data = data;
 }


 public String getTitle() {
   return title;
 }


 public void setTitle(String title) {
   this.title = title;
 }

}

------------------------com.example.Some3.java----- ------------

import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class Some3 {

@SerializedName("data")
@Expose
private String data;
@SerializedName("title")
@Expose
private String title; 

public String getData() {
return data;
}


public void setData(String data) {
 this.data = data;
}


public String getTitle() {
 return title;
}


public void setTitle(String title) {
 this.title = title;
}

} 

这是给你的活动代码，ENJOY!!!

 public class MainActivity extends AppCompatActivity {

 String json = "{\n" +
        "  \"Some1\": {\n" +
        "    \"data\": \"dta\",\n" +
        "    \"title\": \"ttl\"\n" +
        "  },\n" +
        "  \"Some3\": {\n" +
        "    \"data\": \"dta2\",\n" +
        "    \"title\": \"ttl2\"\n" +
        "  }\n" +
        "}";

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Example mExample = new Gson().fromJson(json, Example.class);

    Toast.makeText(this, mExample.toString(), Toast.LENGTH_SHORT).show();
}
}

您也可以使用本网站生成类link

Answer 4

你的课是这样的

package com.example;

import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class Example {

@SerializedName("Some1")
@Expose
private Some1 some1;
@SerializedName("Some3")
@Expose
private Some3 some3;


public Some1 getSome1() {
return some1;
}

public void setSome1(Some1 some1) {
this.some1 = some1;
}

public Some3 getSome3() {
return some3;
}

public void setSome3(Some3 some3) {
this.some3 = some3;
}}

下一个 Some1.class

package com.example;

import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class Some1 {

@SerializedName("data")
@Expose
private String data;
@SerializedName("title")
@Expose
private String title;


public String getData() {
return data;
}

public void setData(String data) {
this.data = data;
}


public String getTitle() {
return title;
}


public void setTitle(String title) {
this.title = title;
}

}

下一个 Some3.class

package com.example;

import com.google.gson.annotations.Expose;
import com.google.gson.annotations.SerializedName;

public class Some3 {

@SerializedName("data")
@Expose
private String data;
@SerializedName("title")
@Expose
private String title;

/**
* 
* @return
* The data
*/
public String getData() {
return data;
}

/**
* 
* @param data
* The data
*/
public void setData(String data) {
this.data = data;
}

/**
* 
* @return
* The title
*/
public String getTitle() {
return title;
}

/**
* 
* @param title
* The title
*/
public void setTitle(String title) {
this.title = title;
}

}