Spring-RestTemplate之urlencode参数解析异常全程分析

@RestController
public class HelloRest {
    public final String ALLOW_KEY = "ASHJRK3LJFD+R32SADFLK+FASDJ=";

    @GetMapping(path = "access")
    public String access(String accessKey, String name) {
        System.out.println(accessKey + "|" + name) ;
        if (ALLOW_KEY.equals(accessKey)) {
            return "true";
        } else {
            return "false";
        }
    }
}

@Test
public void testUrlEncode() {
    String url = "http://localhost:39531/access?accessKey=ASHJRK3LJFD%2BR32SADFLK%2BFASDJ%3D&name=yihuihui";
    RestTemplate restTemplate = new RestTemplate();
    String ans = restTemplate.getForObject(url, String.class);
    System.out.println(ans);
}

@Test
public void testUrlEncode() {
    String url = "http://localhost:39531/access?accessKey=ASHJRK3LJFD%2BR32SADFLK%2BFASDJ%3D&name=yihuihui";
    RestTemplate restTemplate = new RestTemplate();
    String ans = restTemplate.getForObject(url, String.class);
    System.out.println(ans);

    url = "http://localhost:39531/access?accessKey=ASHJRK3LJFD+R32SADFLK+FASDJ=&name=yihuihui";
    ans = restTemplate.getForObject(url, String.class);
    System.out.println(ans);
}

@Test
public void testUrlEncode() throws IOException {
    String url = "http://localhost:39531/access?accessKey=ASHJRK3LJFD%2BR32SADFLK%2BFASDJ%3D&name=yihuihui";
    RestTemplate restTemplate = new RestTemplate();
    String ans = restTemplate.getForObject(url, String.class);
    System.out.println(ans);


    //创建httpclient对象
    CloseableHttpClient httpClient = HttpClients.createDefault();
    //创建请求方法的实例， 并指定请求url
    HttpGet httpget = new HttpGet(url);
    //获取http响应状态码
    CloseableHttpResponse response = httpClient.execute(httpget);
    HttpEntity entity = response.getEntity();
    //接收响应头
    String content = EntityUtils.toString(entity, "utf-8");
    System.out.println(httpget.getURI());
    System.out.println(content);
    httpClient.close();
}

@Test
public void testUrlEncode() throws IOException {
    String url = "http://localhost:39531/access?accessKey=ASHJRK3LJFD%2BR32SADFLK%2BFASDJ%3D&name=yihuihui";
    RestTemplate restTemplate = new RestTemplate();
    String ans = restTemplate.getForObject(url, String.class);
    System.out.println(ans);


    ans = restTemplate.getForObject(URI.create(url), String.class);
    System.out.println(ans);
}

// org.springframework.web.util.DefaultUriBuilderFactory.DefaultUriBuilder#build(java.lang.Object...)

@Override
public URI build(Map<String, ?> uriVars) {
	if (!defaultUriVariables.isEmpty()) {
		Map<String, Object> map = new HashMap<>();
		map.putAll(defaultUriVariables);
		map.putAll(uriVars);
		uriVars = map;
	}
	if (encodingMode.equals(EncodingMode.VALUES_ONLY)) {
		uriVars = UriUtils.encodeUriVariables(uriVars);
	}
	UriComponents uriComponents = this.uriComponentsBuilder.build().expand(uriVars);
	if (encodingMode.equals(EncodingMode.URI_COMPONENT)) {
		uriComponents = uriComponents.encode();
	}
	return URI.create(uriComponents.toString());
}

@Override
public URI build(Object... uriVars) {
	if (ObjectUtils.isEmpty(uriVars) && !defaultUriVariables.isEmpty()) {
		return build(Collections.emptyMap());
	}
	if (encodingMode.equals(EncodingMode.VALUES_ONLY)) {
		uriVars = UriUtils.encodeUriVariables(uriVars);
	}
	UriComponents uriComponents = this.uriComponentsBuilder.build().expand(uriVars);
	if (encodingMode.equals(EncodingMode.URI_COMPONENT)) {
		uriComponents = uriComponents.encode();
	}
	return URI.create(uriComponents.toString());
}

// org.springframework.web.util.HierarchicalUriComponents#encode

@Override
public HierarchicalUriComponents encode(Charset charset) {
	if (this.encoded) {
		return this;
	}
	String scheme = getScheme();
	String fragment = getFragment();
	String schemeTo = (scheme != null ? encodeUriComponent(scheme, charset, Type.SCHEME) : null);
	String fragmentTo = (fragment != null ? encodeUriComponent(fragment, charset, Type.FRAGMENT) : null);
	String userInfoTo = (this.userInfo != null ? encodeUriComponent(this.userInfo, charset, Type.USER_INFO) : null);
	String hostTo = (this.host != null ? encodeUriComponent(this.host, charset, getHostType()) : null);
	PathComponent pathTo = this.path.encode(charset);
	MultiValueMap<String, String> paramsTo = encodeQueryParams(charset);
	return new HierarchicalUriComponents(
			schemeTo, fragmentTo, userInfoTo, hostTo, this.port, pathTo, paramsTo, true, false);
}


// org.springframework.web.util.HierarchicalUriComponents#encodeQueryParams
private MultiValueMap<String, String> encodeQueryParams(Charset charset) {
	int size = this.queryParams.size();
	MultiValueMap<String, String> result = new LinkedMultiValueMap<>(size);
	this.queryParams.forEach((key, values) -> {
		String name = encodeUriComponent(key, charset, Type.QUERY_PARAM);
		List<String> encodedValues = new ArrayList<>(values.size());
		for (String value : values) {
			encodedValues.add(encodeUriComponent(value, charset, Type.QUERY_PARAM));
		}
		result.put(name, encodedValues);
	});
	return result;
}

// org.springframework.web.util.HierarchicalUriComponents#encodeUriComponent(java.lang.String, java.nio.charset.Charset, org.springframework.web.util.HierarchicalUriComponents.Type)
static String encodeUriComponent(String source, Charset charset, Type type) {
	if (!StringUtils.hasLength(source)) {
		return source;
	}
	Assert.notNull(charset, "Charset must not be null");
	Assert.notNull(type, "Type must not be null");

	byte[] bytes = source.getBytes(charset);
	ByteArrayOutputStream bos = new ByteArrayOutputStream(bytes.length);
	boolean changed = false;
	for (byte b : bytes) {
		if (b < 0) {
			b += 256;
		}
		
		// 注意这一行，我们的type实际上为 org.springframework.web.util.HierarchicalUriComponents.Type#QUERY_PARAM
		if (type.isAllowed(b)) {
			bos.write(b);
		}
		else {
			bos.write('%');
			char hex1 = Character.toUpperCase(Character.forDigit((b >> 4) & 0xF, 16));
			char hex2 = Character.toUpperCase(Character.forDigit(b & 0xF, 16));
			bos.write(hex1);
			bos.write(hex2);
			changed = true;
		}
	}
	return (changed ? new String(bos.toByteArray(), charset) : source);
}

// org.springframework.web.util.HierarchicalUriComponents.Type#QUERY_PARAM
QUERY_PARAM {
	@Override
	public boolean isAllowed(int c) {
		if ('=' == c || '&' == c) {
			return false;
		}
		else {
			return isPchar(c) || '/' == c || '?' == c;
		}
	}
},

// isPchar 对应的相关代码为

/**
 * Indicates whether the given character is in the {@code pchar} set.
 * @see <a href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986, appendix A</a>
 */
protected boolean isPchar(int c) {
	return (isUnreserved(c) || isSubDelimiter(c) || ':' == c || '@' == c);
}

/**
 * Indicates whether the given character is in the {@code unreserved} set.
 * @see <a href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986, appendix A</a>
 */
protected boolean isUnreserved(int c) {
	return (isAlpha(c) || isDigit(c) || '-' == c || '.' == c || '_' == c || '~' == c);
}

/**
 * Indicates whether the given character is in the {@code sub-delims} set.
 * @see <a href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986, appendix A</a>
 */
protected boolean isSubDelimiter(int c) {
	return ('!' == c || '$' == c || '&' == c || '\'' == c || '(' == c || ')' == c || '*' == c || '+' == c ||
			',' == c || ';' == c || '=' == c);
}

/**
 * Indicates whether the given character is in the {@code ALPHA} set.
 * @see <a href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986, appendix A</a>
 */
protected boolean isAlpha(int c) {
	return (c >= 'a' && c <= 'z' || c >= 'A' && c <= 'Z');
}

/**
 * Indicates whether the given character is in the {@code DIGIT} set.
 * @see <a href="http://www.ietf.org/rfc/rfc3986.txt">RFC 3986, appendix A</a>
 */
protected boolean isDigit(int c) {
	return (c >= '0' && c <= '9');
}

@Override
@Nullable
public <T> T execute(URI url, @Nullable HttpMethod method, @Nullable RequestCallback requestCallback,
	@Nullable ResponseExtractor<T> responseExtractor) throws RestClientException {

  return doExecute(url, method, requestCallback, responseExtractor);
}

@Override
@Nullable
public <T> T getForObject(URI url, Class<T> responseType) throws RestClientException {
	RequestCallback requestCallback = acceptHeaderRequestCallback(responseType);
	HttpMessageConverterExtractor<T> responseExtractor =
			new HttpMessageConverterExtractor<>(responseType, getMessageConverters(), logger);
	return execute(url, HttpMethod.GET, requestCallback, responseExtractor);
}