Apache CXF实战之八 Map类型绑定

本文链接：http://blog.csdn.net/kongxx/article/details/7544640

Apache CXF实战之一 Hello World Web Service

Apache CXF实战之二 集成Sping与Web容器

Apache CXF实战之三 传输Java对象

Apache CXF实战之四 构建RESTful Web Service

Apache CXF实战之五 压缩Web Service数据

Apache CXF实战之六 创建安全的Web Service

Apache CXF实战之七 使用Web Service传输文件

在CXF中，如果Web Service返回类型是Map的时候，比如方法签名如下

@WebMethod
    @WebResult Map<String, User> getUserMap();

此时如果运行程序会得到类似下面的异常

...
Caused by: com.sun.xml.bind.v2.runtime.IllegalAnnotationsException: 2 counts of IllegalAnnotationExceptions
java.util.Map is an interface, and JAXB can't handle interfaces.
    this problem is related to the following location:
        at java.util.Map
        at private java.util.Map com.googlecode.garbagecan.cxfstudy.type.sample2.jaxws_asm.GetUserMapResponse._return
        at com.googlecode.garbagecan.cxfstudy.type.sample2.jaxws_asm.GetUserMapResponse
java.util.Map does not have a no-arg default constructor.
    this problem is related to the following location:
        at java.util.Map
        at private java.util.Map com.googlecode.garbagecan.cxfstudy.type.sample2.jaxws_asm.GetUserMapResponse._return
        at com.googlecode.garbagecan.cxfstudy.type.sample2.jaxws_asm.GetUserMapResponse
    at com.sun.xml.bind.v2.runtime.IllegalAnnotationsException$Builder.check(IllegalAnnotationsException.java:102)
    at com.sun.xml.bind.v2.runtime.JAXBContextImpl.getTypeInfoSet(JAXBContextImpl.java:472)
    at com.sun.xml.bind.v2.runtime.JAXBContextImpl.<init>(JAXBContextImpl.java:302)
    at com.sun.xml.bind.v2.runtime.JAXBContextImpl$JAXBContextBuilder.build(JAXBContextImpl.java:1136)
    at com.sun.xml.bind.v2.ContextFactory.createContext(ContextFactory.java:154)
    at com.sun.xml.bind.v2.ContextFactory.createContext(ContextFactory.java:121)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at javax.xml.bind.ContextFinder.newInstance(Unknown Source)
    at javax.xml.bind.ContextFinder.newInstance(Unknown Source)
    at javax.xml.bind.ContextFinder.find(Unknown Source)
    at javax.xml.bind.JAXBContext.newInstance(Unknown Source)
    at org.apache.cxf.jaxb.JAXBDataBinding.createContext(JAXBDataBinding.java:560)
    at org.apache.cxf.jaxb.JAXBDataBinding.createJAXBContextAndSchemas(JAXBDataBinding.java:500)
    at org.apache.cxf.jaxb.JAXBDataBinding.initialize(JAXBDataBinding.java:320)
    ... 25 more
...

如果把方法签名改为如下时

@WebMethod
    @WebResult HashMap<String, User> getUserMap();

运行程序会发现返回的结果总是一个空的HashMap。

对于以上问题，此时需要对Map类型做一下数据绑定或者说转换，看下面详细例子

1. 首先是一个实体类

package com.googlecode.garbagecan.cxfstudy.type.sample2;

public class User {
    private String id;
    private String name;
    private String password;
    public String getId() {
        return id;
    }
    public void setId(String id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
}

2. 对Map类型做转换的类和适配器类

package com.googlecode.garbagecan.cxfstudy.type.sample2;

import java.util.HashMap;
import java.util.Map;

import javax.xml.bind.annotation.adapters.XmlAdapter;

public class MapAdapter extends XmlAdapter<MapConvertor, Map<String, Object>> {

    @Override
    public MapConvertor marshal(Map<String, Object> map) throws Exception {
        MapConvertor convertor = new MapConvertor();
        for (Map.Entry<String, Object> entry : map.entrySet()) {
            MapConvertor.MapEntry e = new MapConvertor.MapEntry(entry);
            convertor.addEntry(e);
        }
        return convertor;
    }

    @Override
    public Map<String, Object> unmarshal(MapConvertor map) throws Exception {
        Map<String, Object> result = new HashMap<String, Object>();
        for (MapConvertor.MapEntry e : map.getEntries()) {
            result.put(e.getKey(), e.getValue());
        }
        return result;
    }
}

package com.googlecode.garbagecan.cxfstudy.type.sample2;

import java.util.ArrayList;
import java.util.List;
import java.util.Map;

import javax.xml.bind.annotation.XmlAccessType;
import javax.xml.bind.annotation.XmlAccessorType;
import javax.xml.bind.annotation.XmlType;

@XmlType(name = "MapConvertor")
@XmlAccessorType(XmlAccessType.FIELD)
public class MapConvertor {
    private List<MapEntry> entries = new ArrayList<MapEntry>();

    public void addEntry(MapEntry entry) {
        entries.add(entry);
    }

    public List<MapEntry> getEntries() {
        return entries;
    }
    
    public static class MapEntry {

        private String key;

        private Object value;
        
        public MapEntry() {
            super();
        }

        public MapEntry(Map.Entry<String, Object> entry) {
            super();
            this.key = entry.getKey();
            this.value = entry.getValue();
        }

        public MapEntry(String key, Object value) {
            super();
            this.key = key;
            this.value = value;
        }

        public String getKey() {
            return key;
        }

        public void setKey(String key) {
            this.key = key;
        }

        public Object getValue() {
            return value;
        }

        public void setValue(Object value) {
            this.value = value;
        }
    }
}

3. 下面是WebService接口类，注意其中的@XmlJavaTypeAdapter注解部分

package com.googlecode.garbagecan.cxfstudy.type.sample2;

import java.util.List;
import java.util.Map;

import javax.jws.WebMethod;
import javax.jws.WebResult;
import javax.jws.WebService;
import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;

@WebService
public interface UserService {

    @WebMethod
    @WebResult List<User> getUserList();

    @WebMethod
    @XmlJavaTypeAdapter(MapAdapter.class)
    @WebResult Map<String, User> getUserMap();
}

4. WebService接口实现类

package com.googlecode.garbagecan.cxfstudy.type.sample2;

import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;

public class UserServiceImpl implements UserService {

    public List<User> getUserList() {
        List<User> userList = new ArrayList<User>();
        for (int i = 0; i < 10; i++) {
            User user = new User();
            user.setId("" + i);
            user.setName("user_" + i);
            user.setPassword("password_" + i);
            userList.add(user);
        }
        return userList;
    }

    public Map<String, User> getUserMap() {
        Map<String, User> userMap = new LinkedHashMap<String, User>();
        for (int i = 0; i < 10; i++) {
            User user = new User();
            user.setId("" + i);
            user.setName("user_" + i);
            user.setPassword("password_" + i);
            userMap.put(user.getId(), user);
        }
        return userMap;
    }
}

5. 最后是一个单元测试类

package com.googlecode.garbagecan.cxfstudy.type.sample2;

import java.util.List;
import java.util.Map;

import javax.xml.ws.Endpoint;

import org.apache.cxf.jaxws.JaxWsProxyFactoryBean;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Test;

public class UserServiceTest {

    private static final String address = "http://localhost:9000/ws/type/sample2/userService";
    
    private UserService userService;
    
    @BeforeClass
    public static void setUpBeforeClass() throws Exception {
        Endpoint.publish(address, new UserServiceImpl());
    }
    
    @Before
    public void setUp() throws Exception {
        JaxWsProxyFactoryBean factoryBean = new JaxWsProxyFactoryBean();
        factoryBean.setAddress(address);
        factoryBean.setServiceClass(UserService.class);
        Object obj = factoryBean.create();
        userService = (UserService)obj;
    }

    @After
    public void tearDown() throws Exception {
        userService = null;
    }

    @Test
    public void testGetUserList() {
        Assert.assertNotNull(userService);
        List<User> users = userService.getUserList();
        Assert.assertNotNull(users);
        Assert.assertEquals(10, users.size());
    }

    @Test
    public void testGetUserMap() {
        Assert.assertNotNull(userService);
        Map<String, User> users = userService.getUserMap();
        Assert.assertNotNull(users);
        Assert.assertEquals(10, users.size());
    }

}

6. 运行单元测试类验证上面的实现。