Java Restful Web Services （二）——参数注解1

港控/mmm° 2022-08-07 03:39 180阅读 0赞

本章主要介绍Jersey各种不同的参数注解

[Parameters of a resource method may be annotated with parameter-based annotations to extract information from a request. One of the previous examples presented the use of @PathParam to extract a path parameter from the path component of the request URL that matched the path declared in @Path.][Parameters of a resource method may be annotated with parameter-based annotations to extract information from a request. One of the previous examples presented the use of _PathParam to extract a path parameter from the path component of the request URL that matched the path declared in _Path.]

[@QueryParam is used to extract query parameters from the Query component of the request URL.][Parameters of a resource method may be annotated with parameter-based annotations to extract information from a request. One of the previous examples presented the use of _PathParam to extract a path parameter from the path component of the request URL that matched the path declared in _Path.]

[The @PathParam and the other parameter-based annotations, @MatrixParam, @HeaderParam, @CookieParam, @FormParam obey the same rules as @QueryParam.@MatrixParam extracts information from URL path segments. @HeaderParam extracts information from the HTTP headers. @CookieParam extracts information from the cookies declared in cookie related HTTP headers.][Parameters of a resource method may be annotated with parameter-based annotations to extract information from a request. One of the previous examples presented the use of _PathParam to extract a path parameter from the path component of the request URL that matched the path declared in _Path.]

[@FormParam is slightly special because it extracts information from a request representation that is of the MIME media type `"application/x-www-form-urlencoded"` and conforms to the encoding specified by HTML forms, as described here. This parameter is very useful for extracting information that is POSTed by HTML forms, for example the following extracts the form parameter named "name" from the POSTed form data:][Parameters of a resource method may be annotated with parameter-based annotations to extract information from a request. One of the previous examples presented the use of _PathParam to extract a path parameter from the path component of the request URL that matched the path declared in _Path.]

简单来说@PathParam从请求的URL路径中获取@Path定义的匹配参数，@QueryParam则从请求的URL查询组件元素中获取匹配参数，@MatrixParam从路径段中获取参数信息，@HeaderParam从HTTP请求的Head参数中获取参数值，@CookieParam从Cookie中获取。

示例PathParam、@QueryParam及MatrixParam。稍后示例@Context及@CookieParam。

定义资源类

import java.util.Iterator;
    import java.util.List;
    import java.util.Map.Entry;
    
    import javax.ws.rs.GET;
    import javax.ws.rs.MatrixParam;
    import javax.ws.rs.Path;
    import javax.ws.rs.PathParam;
    import javax.ws.rs.Produces;
    import javax.ws.rs.QueryParam;
    import javax.ws.rs.core.MultivaluedMap;
    import javax.ws.rs.core.PathSegment;
    
    @Path("helloworld")
    public class HelloWorldResource {
    	public static final String CLICHED_MESSAGE = "Hello World!";
    
    	@GET
    	@Path("/before")
    	@Produces("text/plain")
    	public String getHelloBefore() {
    		return "hello before";
    	}
    
    	@GET
    	@Produces("text/plain")
    	public String getHello() {
    		return CLICHED_MESSAGE;
    	}
    
    	@GET
    	@Path("/{param}")
    	@Produces("text/plain")
    	public String getHello(@PathParam("param") String username) {
    		return "Hello Path Param " + username;
    	}
    
    	@GET
    	@Path("/user")
    	@Produces("text/plain")
    	public String getHelloWithQuery(@QueryParam("param") String username) {
    		return "Hello Query Param " + username;
    	}
    
    	@GET
    	@Path("{region:.+}/kaifeng/{district:\\w+}")
    	public String getByAddress(
    			@PathParam("region") final List<PathSegment> region,
    			@PathParam("district") final String district) {
    
    		final StringBuilder result = new StringBuilder();
    		for (final PathSegment pathSegment : region) {
    			result.append(pathSegment.getPath()).append("-");
    		}
    		result.append("kaifeng-" + district);
    		return result.toString();
    
    	}
    
    	@GET
    	@Path("query/{condition}")
    	public String getByCondition(
    			@PathParam("condition") final PathSegment condition) {
    		StringBuilder conditions = new StringBuilder();
    		final MultivaluedMap<String, String> matrixParameters = condition
    				.getMatrixParameters();
    
    		final Iterator<Entry<String, List<String>>> iterator = matrixParameters
    				.entrySet().iterator();
    		while (iterator.hasNext()) {
    			final Entry<String, List<String>> entry = iterator.next();
    			conditions.append(entry.getKey()).append("=");
    			conditions.append(entry.getValue()).append(" ");
    		}
    
    		return conditions.toString();
    	}
    
    	@GET
    	@Path("weather/{condition}")
    	public String getByCondition(
    			@PathParam("condition") final PathSegment condition,
    			@MatrixParam("program") final String program,
    			@MatrixParam("type") final String type) {
    
    		return condition.getPath() + " program = " + program + " type = "
    				+ type;
    	}
    
    }

定义测试类

import static org.junit.Assert.*;
    
    import javax.ws.rs.client.Client;
    import javax.ws.rs.client.ClientBuilder;
    import javax.ws.rs.client.WebTarget;
    
    import org.junit.After;
    import org.junit.AfterClass;
    import org.junit.Before;
    import org.junit.BeforeClass;
    import org.junit.Test;
    
    public class HelloWorldResourceTest {
    
    	private WebTarget target;
    	public static final String BASE_URI = "http://localhost:8090/NoteMail/rest/";
    
    	@BeforeClass
    	public static void setUpBeforeClass() throws Exception {
    		System.out.println("setUpBeforeClass");
    	}
    
    	@AfterClass
    	public static void tearDownAfterClass() throws Exception {
    		System.out.println("tearDownAfterClass");
    	}
    
    	@Before
    	public void setUp() throws Exception {
    		System.out.println("setUp");
    		Client c = ClientBuilder.newClient();
    		target = c.target(BASE_URI);
    		System.out.println(target.getUri());
    	}
    
    	@After
    	public void tearDown() throws Exception {
    		System.out.println("tearDown");
    	}
    
    	
    	
    	@Test
    	public void testGetHello() {
    
    		String responseMsg = target.path("helloworld").request()
    				.get(String.class);		
    		assertEquals("Hello World!", responseMsg);
    		
    	}
    	
    	@Test
    	public void testGetHelloWithPathParam() {
    
    		String responseMsg = target.path("helloworld/ICBC").request().get(String.class);		
    		assertEquals("Hello Path Param ICBC", responseMsg);
    		
    	}
    	
    	
    	@Test
    	public void testGetHelloWithQueryParam() {
    
    		String responseMsg = target.path("helloworld/user").queryParam("param", "ICBC").request().get(String.class);		
    		assertEquals("Hello Query Param ICBC", responseMsg);
    		
    	}
    	
    	
    	@Test
    	public void testGetHelloBefore() {
    
    		String responseMsg = target.path("helloworld/before/").request()
    				.get(String.class);
    		assertEquals("hello before", responseMsg);
    
    	}
    
    	
    	@Test
    	public void testGetByAddress(){
    		String result = target.path("helloworld/China/Henan/kaifeng/gulou").request().get(String.class);
    		assertEquals("China-Henan-kaifeng-gulou", result);
    	}
    
    	@Test	
    	public void testGetByConditionMatrixParameters(){
    		String result = target.path("helloworld/query/restful;program=java;type=web;kind=1,2,3").request().get(String.class);
    		System.out.println(result);
    		assertEquals("program=[java] type=[web] kind=[1,2,3] ", result);
    	}
    	
    	@Test	
    	public void testGetByConditionMatrixParam(){
    		String result = target.path("helloworld/weather/matrixparam;program=java;type=web;kind=1,2,3").request().get(String.class);
    		System.out.println(result);
    		assertEquals("matrixparam program = java type = web", result);
    	}
    	
    	
    }

执行结果

![Center][]

[Parameters of a resource method may be annotated with parameter-based annotations to extract information from a request. One of the previous examples presented the use of _PathParam to extract a path parameter from the path component of the request URL that matched the path declared in _Path.]: https://jersey.java.net/documentation/latest/jaxrs-resources.html#d0e2113
[Center]: /images/20220805/e3941f8b1f6b448b8ae3bb6d38c7f592.png