其他RESTEasy介绍见官网： http://resteasy.jboss.org/。本节简单介绍RESTEasy2+spring4的集成及客户端访问。
1.spring web基础环境
见之前章节创建的web工程testRest。
2.REST地址
与上一节类似，设计RESTEasy模块/resteasy/*。
3.RESTEasy库
在项目pom.xml中加入RESTEasy依赖：
3.0.0.Final ... org.jboss.resteasy resteasy-jaxrs ${resteasy.version} org.jboss.resteasy resteasy-client ${resteasy.version} org.jboss.resteasy resteasy-spring ${resteasy.version} ... org.jboss.resteasy resteasy-jackson-provider ${resteasy.version}
版本使用3.0.0.Final，因为更新的版本要求jdk1.8才能运行。
4.Servlet
配置RESTEasy访问入口。
resteasy.resources com.sunbin.test.resteasy.TeachersResource,com.sunbin.test.resteasy.TeacherResource resteasy.servlet.mapping.prefix /resteasy org.jboss.resteasy.plugins.server.servlet.ResteasyBootstrap resteasy org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher resteasy /resteasy/*
resteasy Servlet将拦截/resteasy/*下的所有访问。
RESTEasy与web、spring集成后，不需要再自己实现Application、Component等组件，也不需要配置文件进行路径配置，仅需要使用@Path注解。
5.实现api
新建com.sunbin.test.resteasy包，新增TeachersResource类，以实现/teachers路径的接口：
package com.sunbin.test.resteasy;
import java.util.HashMap;
import java.util.Map;
import javax.ws.rs.FormParam;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import org.springframework.beans.factory.annotation.Autowired;
import com.sunbin.test.teacher.pojo.Teacher;
import com.sunbin.test.teacher.service.TeacherService;
@Path("/teachers")
@Produces(MediaType.APPLICATION_JSON)
public class TeachersResource {
@Autowired
private TeacherService teacherService;
@GET
public Map get() {
System.out.println("Resteasy TeachersResource.get");
Map map = new HashMap();
map.put("teachers", teacherService.list());
return map;
}
@POST
public Map post(@FormParam("age") int age, @FormParam("name") String name) {
Map map = new HashMap();
try {
Teacher teacher = new Teacher();
teacher.setName(name);
teacher.setAge(age);
System.out.println("Resteasy TeachersResource.post:" + teacher);
teacherService.save(teacher);
map.put("status", "y");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return map;
}
}
路径注解@Path、返回类型注解@Produces、访问方法@GET、参数读取@FormParam，都和Jersey的JAX-RS相同。
重新部署项目后，访问 http://localhost:8080/testRest/resteasy/teachers，发现报错：
java.lang.NullPointerException
com.sunbin.test.resteasy.TeachersResource.get(TeachersResource.java:29)
检查后发现是teacherService.list()语句中teacherService为null，@Autowired注解没有生效。
尝试使用xml配置方式实现teacherService注入，或使用jsr规范自有的@Inject、@Resource注解也不生效。
为什么会这样？分析是因为RESTEasy和spring的beanfactory之间依赖注入的问题。
RESTEasy官网手册推荐以下两种解决方法：
1.通过WebApplicationContextUtils工具类获取ApplicationContext对象
2.自定义工具类
具体使用方法见我之前的文章： spring4学习（三）在非Spring类中获取Bean
为了方便注入，这里采用第二种方法：定义Context工具类SpringContextHolder并配置至spring。之后需要对Resource类进行改造：
package com.sunbin.test.resteasy;
import java.util.HashMap;
import java.util.Map;
import javax.ws.rs.FormParam;
import javax.ws.rs.GET;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import com.sunbin.common.spring.SpringContextHolder;
import com.sunbin.test.teacher.pojo.Teacher;
import com.sunbin.test.teacher.service.TeacherService;
@Path("/teachers")
@Produces(MediaType.APPLICATION_JSON)
public class TeachersResource {
private TeacherService teacherService;
public TeachersResource() {
super();
// 不能自动注入，需要手动getBean赋值
teacherService = (TeacherService) SpringContextHolder
.getBean("teacherService");
// TODO Auto-generated constructor stub
}
@GET
public Map get() {
System.out.println("Resteasy TeachersResource.get");
Map map = new HashMap();
map.put("teachers", teacherService.list());
return map;
}
@POST
public Map post(@FormParam("age") int age, @FormParam("name") String name) {
Map map = new HashMap();
try {
Teacher teacher = new Teacher();
teacher.setName(name);
teacher.setAge(age);
System.out.println("Resteasy TeachersResource.post:" + teacher);
teacherService.save(teacher);
map.put("status", "y");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return map;
}
}
在TeachersResource类的构造方法中手动通过SpringContextHolder获取Bean，再赋值给resource。
同样的，新增TeacherResource类，以实现/teacher/{id}路径的接口：
package com.sunbin.test.resteasy;
import java.util.HashMap;
import java.util.Map;
import javax.ws.rs.DELETE;
import javax.ws.rs.FormParam;
import javax.ws.rs.GET;
import javax.ws.rs.PUT;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import com.sunbin.common.spring.SpringContextHolder;
import com.sunbin.test.teacher.pojo.Teacher;
import com.sunbin.test.teacher.service.TeacherService;
@Path("teacher/{id}")
@Produces(MediaType.APPLICATION_JSON)
public class TeacherResource {
private TeacherService teacherService;
public TeacherResource() {
super();
teacherService = (TeacherService) SpringContextHolder
.getBean("teacherService");
// TODO Auto-generated constructor stub
}
@GET
public Map get(@PathParam("id") int id) {
System.out.println("Resteasy TeacherResource.get:" + id);
Teacher teacher = new Teacher();
teacher.setId(id);
Map map = new HashMap();
map.put("teacher", teacherService.get(teacher));
return map;
}
@PUT
public Map put(@PathParam("id") int id, @FormParam("age") int age,
@FormParam("name") String name) {
Map map = new HashMap();
try {
Teacher teacher = new Teacher();
teacher.setId(id);
teacher.setName(name);
teacher.setAge(age);
System.out.println("Resteasy TeacherResource.put:" + id + ":"
+ teacher);
teacherService.update(teacher);
map.put("status", "y");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return map;
}
@DELETE
public Map delete(@PathParam("id") int id) {
Map map = new HashMap();
try {
System.out.println("Resteasy TeacherResource.delete:" + id);
Teacher teacher = new Teacher();
teacher.setId(id);
teacherService.remove(teacher);
map.put("status", "y");
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return map;
}
}
6.js测试
使用上一节的测试页面src\main\webapp\rest\index.jsp进行测试：
...