Activiti工作流REST方式访问URI的解析
在Activiti工作流中提供一种访问方式为REST方式访问。针对查询字符串的格式采用一个如下一个工具类解析Uri中的提供的各种信息。
package org.activiti.explorer.util;
import java.io.UnsupportedEncodingException;
import java.net.URLDecoder;
import java.net.URLEncoder;
import java.util.ArrayList;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Scanner;
/**
* @author 'Frederik Heremans'
*/
public class UriUtility {
private static final String PARAMETER_SEPARATOR = "&";
private static final String QUERY_STRING_SEPARATOR = "?";
private static final String NAME_VALUE_SEPARATOR = "=";
private static final String URL_PART_SEPARATOR = "/";
/**
* Get path fragments. eg: "/task/inbox/123" will return a list with three
* values: "task", "inbox" and "123" in that order.
*/
public static List<String> getFragmentParts(String url) {
if (url != null) {
List<String> parts = new ArrayList<String>();
String[] partsArray = url.split(URL_PART_SEPARATOR);
for (String part : partsArray) {
if (part.length() > 0) {
parts.add(part);
}
}
return parts;
}
return null;
}
/**
* Extracts the query parameters from the given url fragment.
*/
public static String extractQueryString(String fragment) {
if (fragment != null) {
int firstIndex = fragment.indexOf(QUERY_STRING_SEPARATOR);
if (firstIndex >= 0) {
return fragment.substring(firstIndex);
}
}
return null;
}
/**
* Extracts uri from the given url fragment, without the query params.
*/
public static String extractUri(String fragment) {
if (fragment != null) {
int firstIndex = fragment.indexOf(QUERY_STRING_SEPARATOR);
if (firstIndex >= 0) {
return fragment.substring(0, firstIndex);
} else {
// No query string present, use full fragment
return fragment;
}
}
return null;
}
/**
* Parses the parameters from the given url query string. When no encoding is
* passed, default UTF-8 is used. Based on the implementation in Commons
* httpclient UrlEncodedUtils.
*/
public static Map<String, String> parseQueryParameters(String queryString, String encoding) {
Map<String, String> parameters = new LinkedHashMap<String, String>();
if (queryString != null) {
// Remove '?' if present at beginning of query-string
if(queryString.startsWith(QUERY_STRING_SEPARATOR)) {
queryString = queryString.substring(1);
}
Scanner scanner = new Scanner(queryString);
scanner.useDelimiter(PARAMETER_SEPARATOR);
while (scanner.hasNext()) {
final String[] nameValue = scanner.next().split(NAME_VALUE_SEPARATOR);
if (nameValue.length == 0 || nameValue.length > 2)
throw new IllegalArgumentException("bad parameter");
final String name = decode(nameValue[0], encoding);
String value = null;
if (nameValue.length == 2) {
value = decode(nameValue[1], encoding);
}
parameters.put(name, value);
}
}
return parameters;
}
/**
* Gets a valid query-string based on the given parameters.
*/
public static String getQueryString(Map<String, String> parameters) {
StringBuilder result = new StringBuilder();
if (parameters != null) {
for (Entry<String, String> param : parameters.entrySet()) {
final String encodedName = encode(param.getKey(), null);
final String value = param.getValue();
final String encodedValue = value != null ? encode(value, null) : "";
if (result.length() > 0) {
result.append(PARAMETER_SEPARATOR);
} else {
result.append(QUERY_STRING_SEPARATOR);
}
result.append(encodedName);
result.append(NAME_VALUE_SEPARATOR);
result.append(encodedValue);
}
}
return result.toString();
}
/**
* Gets full path based on the given parts.
*/
public static String getPath(List<String> parts) {
if (parts != null) {
StringBuilder result = new StringBuilder();
for (String part : parts) {
if(result.length() > 0) {
result.append(URL_PART_SEPARATOR);
}
result.append(part);
}
return result.toString();
}
return "";
}
private static String decode(final String content, final String encoding) {
try {
return URLDecoder.decode(content, encoding != null ? encoding : "UTF-8");
} catch (UnsupportedEncodingException problem) {
throw new IllegalArgumentException(problem);
}
}
private static String encode(final String content, final String encoding) {
try {
return URLEncoder.encode(content, encoding != null ? encoding : "UTF-8");
} catch (UnsupportedEncodingException problem) {
throw new IllegalArgumentException(problem);
}
}
}