Spring Restful API 取值練習
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參考:
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版本 Spring 4.x
Dependencies
pom.xml
<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-annotations -->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-annotations</artifactId>
<version>2.8.6</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-core -->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-core</artifactId>
<version>2.8.6</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.core/jackson-databind -->
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.8.6</version>
</dependency>
<!-- https://mvnrepository.com/artifact/com.fasterxml.jackson.dataformat/jackson-dataformat-xml -->
<dependency>
<groupId>com.fasterxml.jackson.dataformat</groupId>
<artifactId>jackson-dataformat-xml</artifactId>
<version>2.8.6</version>
</dependency>
向 RESTful server 取 String 資料
- 取得 JASON String 並自行使用 ObjectMapper 轉換成指定型別
//向 RESTful server 取資料範例
import org.springframework.web.client.RestTemplate;
------------------------------------------------------------
RestTemplate restTemplate = new RestTemplate();
String uri = "http://opendata.cwb.gov.tw/opendataapi?dataid=F-A0012-001&authorizationkey=CWB-936FC500-F62C-487C-95C9-BB17DD188132";
String result = restTemplate.getForObject(uri, String.class);
System.out.println("2----------------------"+result);
// 自行 parse JSON 成 JsonResp.class 範例
import com.fasterxml.jackson.databind.ObjectMapper;
------------------------------------------------------------
String test ="{'type':'success','value':{'id':3,'quote':'Spring has come quite a ways in addressing developer enjoyment and ease of use since the last time I built an application using it.'}}";
ObjectMapper mapper = new ObjectMapper();
try {
JsonResp read = mapper.readValue(test, JsonResp.class);
System.out.println(read.getType()); // Enum
System.out.println(read.getValue().getId()); //Long
System.out.println(read.getValue().getQuote()); //String
} catch (IOException e) {
throw new RuntimeException("unexpected", e);
}
向 RESTful server 取 POJO 資料
- 直接將 server 端資料轉成指定 Entity
- 可以是 composite 結構
指定 POJO 型別: Quote and Value class
- @JsonIgnoreProperties(ignoreUnknown = true) : 忽略 JSON 中有出現，但 Entity 中不打算 mapping 的資料
Quote.java
package insect.totem.restful;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
@JsonIgnoreProperties(ignoreUnknown = true)
public class Quote {
private String type;
private Value value; // composite
public Quote() {
}
@Override
public String toString() {
return "Quote{" +
"type='" + type + '\'' +
", value=" + value +
'}';
}
getters/setters...
}
Value.java
package insect.totem.restful;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
@JsonIgnoreProperties(ignoreUnknown = true)
public class Value {
private Long id;
private String quote;
public Value() {}
public Long getId() {
return this.id;
}
public String getQuote() {
return this.quote;
}
public void setId(Long id) {
this.id = id;
}
public void setQuote(String quote) {
this.quote = quote;
}
@Override
public String toString() {
return "Value{" + "id=" + id + ", quote='" + quote + '\'' + '}';
}
}
Restful Service
- 搭配 restTemplate.getForObject() method
//向 RESTful server 取資料範例
import org.springframework.web.client.RestTemplate;
------------------------------------------------------------
//Test JSON
RestTemplate restTemplate = new RestTemplate();
String uri = "http://gturnquist-quoters.cfapps.io/api/random";
Quote result = restTemplate.getForObject(uri, Quote .class);
向 RESTful server 取集合資料
- 搭配 restTemplate.getForEntity() method
// 若restful server回傳的是collection資料
RestTemplate restTemplate = new RestTemplate();
String uri = "http://localhost:8080/insect/totem/collection";
ResponseEntity<JsonResp[]> responseEntity = restTemplate.getForEntity(uri, JsonResp[].class);
JsonResp[] data = responseEntity.getBody();
向 RESTful server 取 xml 資料
- 向氣象局取 xml 資料
目標結果格式: cwbopendata.java
- POJO 內的 attribute 與 XML 中的 element 須同名
- 或是以 @JacksonXmlProperty(localName = "identifier") 指定, element 名稱
- @JsonIgnoreProperties(ignoreUnknown = true) : 忽略 XML 中有出現的 elements ，但 Entity 中不打算 mapping 的資料
package insect.totem.restful;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlRootElement;
@JacksonXmlRootElement
@JsonIgnoreProperties(ignoreUnknown = true)
public class cwbopendata {
@JacksonXmlProperty(localName = "identifier")
private String identifier__;
@JacksonXmlProperty(localName = "sender")
private String sender;
@JacksonXmlProperty(localName = "sent")
private String sent;
@JacksonXmlProperty(localName = "status")
private String status;
getters/setters...
}
RestService: XmlMapper
- 先取得 String 再搭配使用 XmlMapper
RestTemplate restTemplate = new RestTemplate();
String text = restTemplate.getForObject(
"http://opendata.cwb.gov.tw/opendataapi?dataid=F-A0012-001&authorizationkey=CWB-936FC500-F62C-487C-95C9-BB17DD188132",
String.class);
XmlMapper mapper = new XmlMapper();
try {
cwbopendata value =
mapper.readValue(text, cwbopendata.class);
System.out.println("-------------------------------------------");
System.out.println(text);
System.out.println("-------------------------------------------");
System.out.println(value.getIdentifier__());
System.out.println(value.getSender());
System.out.println(value.getSent());
System.out.println(value.getStatus());
} catch (IOException e) {
throw new RuntimeException("unexpected", e);
}
RestService: POJO
- 直接將 xml 轉 Entity
RestTemplate restTemplate = new RestTemplate();
cwbopendata value = restTemplate.getForObject(
"http://opendata.cwb.gov.tw/opendataapi?dataid=F-A0012-001&authorizationkey=CWB-936FC500-F62C-487C-95C9-BB17DD188132",
cwbopendata.class);
System.out.println(value.getIdentifier__());
System.out.println(value.getSender());
System.out.println(value.getSent());
System.out.println(value.getStatus());