Jersey框架二：Jersey对JSON的支持

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());
    }
}