Jersey框架二：Jersey对JSON的支持

时间：2022-04-27 08:45:38

Jersey系列文章：

Jersey框架一：Jersey RESTful WebService框架简介

Jersey框架二：Jersey对JSON的支持

Jersey框架三：Jersey对HTTPS的支持

Jersey提供3种基本方式来使用JSON格式

无论使用何种方式，在原有包的基础上，都需要在客户端和服务端Maven配置文件中添加jersey-json包以支持JSON格式

<dependency>

    <groupId>com.sun.jersey</groupId>

    <artifactId>jersey-json</artifactId>

    <version>1.18</version>

</dependency>

一，基于POJO

Request类和Response类（服务端和客户端都需要）都是基本的POJO：

package com.sean;  

public class Request {

    private String query;  

    public String getQuery() {

        return query;

    }  

    public void setQuery(String query) {

        this.query = query;

    }

}  
package com.sean;  

public class Response {

    private int respCode;

    private String respDesc;  

    public int getRespCode() {

        return respCode;

    }  

    public void setRespCode(int respCode) {

        this.respCode = respCode;

    }  

    public String getRespDesc() {

        return respDesc;

    }  

    public void setRespDesc(String respDesc) {

        this.respDesc = respDesc;

    }

}

服务端代码：

package com.sean;  

import java.io.IOException;

import java.net.URI;  

import javax.ws.rs.Consumes;

import javax.ws.rs.POST;

import javax.ws.rs.Path;

import javax.ws.rs.Produces;

import javax.ws.rs.core.MediaType;

import javax.ws.rs.core.UriBuilder;  

import org.glassfish.grizzly.http.server.HttpServer;  

import com.sun.jersey.api.container.grizzly2.GrizzlyServerFactory;

import com.sun.jersey.api.core.PackagesResourceConfig;

import com.sun.jersey.api.core.ResourceConfig;

import com.sun.jersey.api.json.JSONConfiguration;  

@Path("query")

public class MyResource {  

    @POST

    @Consumes(MediaType.APPLICATION_JSON)

    @Produces(MediaType.APPLICATION_JSON)

    public Response query(Request req) {

        System.out.println(req.getQuery());  

        Response resp = new Response();

        resp.setRespCode(0);

        resp.setRespDesc(req.getQuery());

        return resp;

    }  

    public static void main(String[] args) {

        URI uri = UriBuilder.fromUri("http://127.0.0.1").port(10000).build();

        ResourceConfig rc = new PackagesResourceConfig("com.sean");

        //使用Jersey对POJO的支持，必须设置为true

         rc.getFeatures().put(JSONConfiguration.FEATURE_POJO_MAPPING, true);

        try {

            HttpServer server = GrizzlyServerFactory.createHttpServer(uri, rc);

            server.start();

        } catch (IllegalArgumentException e) {

            e.printStackTrace();

        } catch (NullPointerException e) {

            e.printStackTrace();

        } catch (IOException e) {

            e.printStackTrace();

        }

        try {

            Thread.sleep(1000*1000);

        } catch (InterruptedException e) {

            e.printStackTrace();

        }

    }

}

客户端代码：

package com.sean;  

import javax.ws.rs.core.MediaType;  

import com.sun.jersey.api.client.Client;

import com.sun.jersey.api.client.ClientResponse;

import com.sun.jersey.api.client.WebResource;

import com.sun.jersey.api.client.config.ClientConfig;

import com.sun.jersey.api.client.config.DefaultClientConfig;

import com.sun.jersey.api.json.JSONConfiguration;  

public class JerseyClient {  

    public static void main(String[] args) {

        ClientConfig cc = new DefaultClientConfig();

        //使用Jersey对POJO的支持，必须设置为true

        cc.getFeatures().put(JSONConfiguration.FEATURE_POJO_MAPPING, Boolean.TRUE);

        Client client = Client.create(cc);  

        WebResource resource = client.resource("http://127.0.0.1:10000/query");  

        Request req = new Request();

        req.setQuery("name");  

        ClientResponse response = resource

                .accept(MediaType.APPLICATION_JSON)

                .type(MediaType.APPLICATION_JSON)

                .post(ClientResponse.class, req);  

        Response resp = response.getEntity(Response.class);

        System.out.println(resp.getRespCode() + " " + resp.getRespDesc());

    }

}

二，基于JAXB

使用JAXB的优点在于，无论使用XML格式还是JSON格式数据，都可以使用统一的Java模型

缺点很难找到一个合适的方式来生成特殊的JSON格式，这也是Jersey提供很多控制选项的原因

将Request类和Response类进行修改：

package com.sean;  

import javax.xml.bind.annotation.XmlRootElement;  

@XmlRootElement

public class Request {

    private String query;  

    public String getQuery() {

        return query;

    }  

    public void setQuery(String query) {

        this.query = query;

    }

}  
package com.sean;  

import javax.xml.bind.annotation.XmlRootElement;  

@XmlRootElement

public class Response {

    private int respCode;

    private String respDesc;  

    public int getRespCode() {

        return respCode;

    }  

    public void setRespCode(int respCode) {

        this.respCode = respCode;

    }  

    public String getRespDesc() {

        return respDesc;

    }  

    public void setRespDesc(String respDesc) {

        this.respDesc = respDesc;

    }

}

服务端代码去掉下面的配置

//       rc.getFeatures().put(JSONConfiguration.FEATURE_POJO_MAPPING, true);

客户端代码去掉下面的配置

//      cc.getFeatures().put(JSONConfiguration.FEATURE_POJO_MAPPING, Boolean.TRUE);

Jersey提供很多控制选项以便更精细的控制JSON的解析、组装过程，但是就我个人来看，JAXB提供的标签足够使用了

三，基于底层JSONObject/JSONArray

最大的优势在于可以完全控制JSON的解析、组装过程，相应的，在处理数据对象时也要更复杂

服务端代码如下：

package com.sean;  

import java.io.IOException;

import java.net.URI;  

import javax.ws.rs.Consumes;

import javax.ws.rs.POST;

import javax.ws.rs.Path;

import javax.ws.rs.Produces;

import javax.ws.rs.core.MediaType;

import javax.ws.rs.core.UriBuilder;  

import org.codehaus.jettison.json.JSONException;

import org.codehaus.jettison.json.JSONObject;

import org.glassfish.grizzly.http.server.HttpServer;  

import com.sun.jersey.api.container.grizzly2.GrizzlyServerFactory;

import com.sun.jersey.api.core.PackagesResourceConfig;

import com.sun.jersey.api.core.ResourceConfig;  

@Path("query")

public class MyResource {  

    @POST

    @Consumes(MediaType.APPLICATION_JSON)

    @Produces(MediaType.APPLICATION_JSON)

    public JSONObject query(JSONObject query) {

        //{"query":"name"}

        System.out.println(query.toString());  

        JSONObject resp = new JSONObject();

        try {

            resp.put("respCode", 0);

            resp.put("respDesc", query.get("query"));

        } catch (JSONException e) {

            e.printStackTrace();

        }

        return resp;

    }  

    public static void main(String[] args) {

        URI uri = UriBuilder.fromUri("http://127.0.0.1").port(10000).build();

        ResourceConfig rc = new PackagesResourceConfig("com.sean");

        try {

            HttpServer server = GrizzlyServerFactory.createHttpServer(uri, rc);

            server.start();

        } catch (IllegalArgumentException e) {

            e.printStackTrace();

        } catch (NullPointerException e) {

            e.printStackTrace();

        } catch (IOException e) {

            e.printStackTrace();

        }

        try {

            Thread.sleep(1000*1000);

        } catch (InterruptedException e) {

            e.printStackTrace();

        }

    }

}

客户端代码如下：

package com.sean;  

import javax.ws.rs.core.MediaType;  

import org.codehaus.jettison.json.JSONException;

import org.codehaus.jettison.json.JSONObject;  

import com.sun.jersey.api.client.Client;

import com.sun.jersey.api.client.ClientResponse;

import com.sun.jersey.api.client.WebResource;

import com.sun.jersey.api.client.config.ClientConfig;

import com.sun.jersey.api.client.config.DefaultClientConfig;  

public class JerseyClient {  

    public static void main(String[] args) {

        ClientConfig cc = new DefaultClientConfig();

        Client client = Client.create(cc);  

        WebResource resource = client.resource("http://127.0.0.1:10000/query");  

        JSONObject req = new JSONObject();

        try {

            req.put("query", "name");

        } catch (JSONException e) {

            e.printStackTrace();

        }  

        ClientResponse response = resource

                .accept(MediaType.APPLICATION_JSON)

                .type(MediaType.APPLICATION_JSON)

                .post(ClientResponse.class, req);  

        JSONObject resp = response.getEntity(JSONObject.class);

        //{"respCode":0,"respDesc":"name"}

        System.out.println(resp.toString());

    }

}

与JAXB相比，结果是相同的，但是处理过程（主要是组装JSON对象）要复杂

对于上面3种方式，均可使用String类代替Request类、Response类或JSONObject类，Jersey会自动将对象转换为JSON串

当然，如果客户端修改为String，服务端也要相应的修改为String类型

修改客户端代码：

public class JerseyClient {  

    public static void main(String[] args) {

        ClientConfig cc = new DefaultClientConfig();

        Client client = Client.create(cc);  

        WebResource resource = client.resource("http://127.0.0.1:10000/query");  

        JSONObject req = new JSONObject();

        try {

            req.put("query", "name");

        } catch (JSONException e) {

            e.printStackTrace();

        }  

        String response = resource

                .accept(MediaType.APPLICATION_JSON)

                .type(MediaType.APPLICATION_JSON)

                .post(String.class, req.toString());

    }

}

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