我想知道是否有任何Java API可用于将POJO对象转换为JSON对象,反之亦然。
[编辑]想象一下,您有一个简单的Java类,如下所示:
public class Person {
private String name;
private Integer age;
public String getName() { return this.name; }
public void setName( String name ) { this.name = name; }
public Integer getAge() { return this.age; }
public void setAge( Integer age ) { this.age = age; }
}
因此,将其转换为JSon对象非常简单。像这样:
import org.json.JSONObject;
public class JsonTest {
public static void main( String[] args ) {
Person person = new Person();
person.setName( "Person Name" );
person.setAge( 333 );
JSONObject jsonObj = new JSONObject( person );
System.out.println( jsonObj );
}
}
希望能帮助到你。
[编辑]这里还有其他示例,在这种情况下使用杰克逊:https : //brunozambiazi.wordpress.com/2015/08/15/working-with-json-in-java/
Maven:
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.6.1</version>
</dependency>
以及一个链接(在下面)以找到最新/最新版本:
我们还可以在pom文件中利用以下给定的依赖关系和插件-我利用了maven。借助这些,您可以根据JSON Schema生成POJO,然后利用下面给出的代码通过指定为gson.toJson(Object src)参数的src对象填充请求JSON对象,反之亦然。看下面的代码:
Gson gson = new GsonBuilder().create();
String payloadStr = gson.toJson(data.getMerchant().getStakeholder_list());
Gson gson2 = new Gson();
Error expectederr = gson2.fromJson(payloadStr, Error.class);
和Maven设置:
<dependency>
<groupId>com.google.code.gson</groupId>
<artifactId>gson</artifactId>
<version>1.7.1</version>
</dependency>
<plugin>
<groupId>com.googlecode.jsonschema2pojo</groupId>
<artifactId>jsonschema2pojo-maven-plugin</artifactId>
<version>0.3.7</version>
<configuration>
<sourceDirectory>${basedir}/src/main/resources/schema</sourceDirectory>
<targetPackage>com.example.types</targetPackage>
</configuration>
<executions>
<execution>
<phase>generate-sources</phase>
<goals>
<goal>generate</goal>
</goals>
</execution>
</executions>
</plugin>
如果您了解Jackson 2,mkyong.com上有一个很棒的教程,介绍如何将Java对象转换为JSON,反之亦然。以下代码段摘自该教程。
将Java对象转换为JSON writeValue(...)
:
ObjectMapper mapper = new ObjectMapper();
Staff obj = new Staff();
//Object to JSON in file
mapper.writeValue(new File("c:\\file.json"), obj);
//Object to JSON in String
String jsonInString = mapper.writeValueAsString(obj);
将JSON转换为Java对象readValue(...)
:
ObjectMapper mapper = new ObjectMapper();
String jsonInString = "{'name' : 'mkyong'}";
//JSON from file to Object
Staff obj = mapper.readValue(new File("c:\\file.json"), Staff.class);
//JSON from URL to Object
Staff obj = mapper.readValue(new URL("http://mkyong.com/api/staff.json"), Staff.class);
//JSON from String to Object
Staff obj = mapper.readValue(jsonInString, Staff.class);
杰克逊2依赖:
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.6.3</version>
</dependency>
有关完整的教程,请转到上面给出的链接。
您可以使用杰克逊API进行转换
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.9.4</version>
</dependency>
在您的POM中添加上述Maven依赖项,在您的主要方法中创建ObjectMapper
ObjectMapper mapper = new ObjectMapper();
mapper.enable(SerializationFeature.INDENT_OUTPUT);
稍后我们需要将我们的POJO类添加到映射器
String json = mapper.writeValueAsString(pojo);
采取以下参考将JSON转换为POJO,反之亦然
假设您的JSON模式如下所示:
{
"type":"object",
"properties": {
"dataOne": {
"type": "string"
},
"dataTwo": {
"type": "integer"
},
"dataThree": {
"type": "boolean"
}
}
}
然后隐匿到POJO中,您需要清除一些类,如以下样式中所述:
==================================
package ;
public class DataOne
{
private String type;
public void setType(String type){
this.type = type;
}
public String getType(){
return this.type;
}
}
==================================
package ;
public class DataTwo
{
private String type;
public void setType(String type){
this.type = type;
}
public String getType(){
return this.type;
}
}
==================================
package ;
public class DataThree
{
private String type;
public void setType(String type){
this.type = type;
}
public String getType(){
return this.type;
}
}
==================================
package ;
public class Properties
{
private DataOne dataOne;
private DataTwo dataTwo;
private DataThree dataThree;
public void setDataOne(DataOne dataOne){
this.dataOne = dataOne;
}
public DataOne getDataOne(){
return this.dataOne;
}
public void setDataTwo(DataTwo dataTwo){
this.dataTwo = dataTwo;
}
public DataTwo getDataTwo(){
return this.dataTwo;
}
public void setDataThree(DataThree dataThree){
this.dataThree = dataThree;
}
public DataThree getDataThree(){
return this.dataThree;
}
}
==================================
package ;
public class Root
{
private String type;
private Properties properties;
public void setType(String type){
this.type = type;
}
public String getType(){
return this.type;
}
public void setProperties(Properties properties){
this.properties = properties;
}
public Properties getProperties(){
return this.properties;
}
}
使用GSON将POJO转换为JSONObject。请参考这里。
要将JSONObject转换为POJO,只需在POJO中调用setter方法并直接从JSONObject分配值即可。
文章标签:java , json , pojo
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