XML与JSON互相转化工具类
需要用到的net.sf.json和org.dom4j
本例用的包为：
json-lib-2.4-jdk15.jar
dom4j-1.6.1.jar
引入包之后，直接复制下面这个工具类使用
package com.java;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
import org.dom4j.Document;
import org.dom4j.DocumentException;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;
import java.io.*;
import java.util.Arrays;
import java.util.List;
/**
* JSON与XML互转，工具类
*/
public class JsonXmlUtil {
private static final char EOFC = (char) -1;
/**
* JSON 转 XML
*
* @param jsonString JSON字符串
*/
public static String getXmlFromJson(String jsonString) throws IOException {
InputStream in = new ByteArrayInputStream(jsonString.getBytes());
ByteArrayOutputStream out = new ByteArrayOutputStream();
translate(in, out);
return out.toString();
}
/**
* 将xml转换为JSON对象
*
* @param xml xml字符串
*/
public static JSONObject getJsonFromXml(String xml) throws Exception {
return getJsonFromXml(xml, "");
}
/**
* 将xml转换为JSON对象
*
* @param xml xml字符串
* @param parseArrayNames （如果xml中的一个节点不是数组，而你又需要将它转化为json数组），请填写该节点名称，多个值时用逗号分隔
* @return
* @throws Exception
*/
public static JSONObject getJsonFromXml(String xml, String parseArrayNames) throws DocumentException {
JSONObject jsonObject = new JSONObject();
Document document = DocumentHelper.parseText(xml);
//获取根节点元素对象
Element root = document.getRootElement();
iterateNodes(root, jsonObject, parseArrayNames);
return jsonObject;
}
/**
* 将 JSON输入流 转化为 XML输出流
*/
private static void translate(InputStream in, OutputStream out) throws IOException, IllegalArgumentException {
InputStreamReader re = new InputStreamReader(in);
char c;
while ((c = (char) re.read()) != EOFC) {
switch (c) {
case '{':
translateObject(re, out);
break;
case '[':
translateArray(re, out, null);
break;
default:
if (Character.isSpaceChar(c)) {
break;
} else {
throw new IllegalArgumentException("invalid character:" + c + " (" + (int) c + ")");
}
}
}
}
private static void translateArray(InputStreamReader re, OutputStream out, String tname) throws IOException, IllegalArgumentException {
char c;
while ((c = (char) re.read()) != EOFC) {
switch (c) {
case '{':
translateObject(re, out);
break;
case '[':
translateArray(re, out, tname);
break;
case ',':
if (tname != null) {
out.write(".getBytes());
out.write(tname.getBytes());
out.write("><".getBytes());
out.write(tname.getBytes());
out.write(">".getBytes());
}
break;
case ']':
return;
case '"':
String n = readStringToken(re);
if (n != null) {
out.write(n.getBytes());
}
break;
default:
if (Character.isSpaceChar(c)) {
break;
} else {
out.write(("" + c).getBytes());
}
}
}
}
private static String readStringToken(InputStreamReader re) throws IOException {
StringBuilder b = new StringBuilder();
char c;
boolean esc = false;
while ((c = (char) re.read()) != EOFC) {
switch (c) {
case '\\':
esc = true;
break;
case 'n':
if (!esc) {
b.append(c);
} else {
b.append((char) 10);
esc = false;
}
break;
case 'r':
if (!esc) {
b.append(c);
} else {
b.append((char) 13);
esc = false;
}
break;
case 't':
if (!esc) {
b.append(c);
} else {
b.append((char) 9);
esc = false;
}
break;
case 'u':
if (!esc) {
b.append(c);
} else {
StringBuilder sb = new StringBuilder(6);
sb.append("0x");
sb.append((char) re.read());
sb.append((char) re.read());
sb.append((char) re.read());
sb.append((char) re.read());
b.append((char) Integer.decode(sb.toString()).intValue());
esc = false;
}
break;
case '"':
if (!esc) {
return b.toString();
}
default:
b.append(c);
esc = false;
}
}
return b.toString();
}
private static boolean translateValue(InputStreamReader re, OutputStream out, String tname) throws IOException, IllegalArgumentException {
char c;
while ((c = (char) re.read()) != EOFC) {
switch (c) {
case '[':
translateArray(re, out, tname);
return false;
case '{':
translateObject(re, out);
return false;
case '"':
String v = readStringToken(re);
outs(out, v);
return false;
case 'n':
re.read(); // u
re.read(); // l
re.read(); // l
return false;
case ' ':
break;
case '}':
return true;
case ',':
return false;
default:
outc(out, c);
break;
}
}
return false;
}
private static void outs(OutputStream out, String s) throws IOException {
if (s != null) {
for (int i = 0, l = s.length(); i < l; i++) {
outc(out, s.charAt(i));
}
}
}
private static void outc(OutputStream out, char c) throws IOException {
switch (c) {
case '<':
out.write("<".getBytes());
break;
case '>':
out.write(">".getBytes());
break;
case '\"':
out.write(""".getBytes());
break;
case '&':
out.write("&".getBytes());
break;
case '\'':
out.write("'".getBytes());
break;
default:
// if (c > 0x7f) {
// if (c < 0x400 || c > 0x4FF) {
// out.write(("&#" + ((int) c) + ";").getBytes());
// } else {
// out.write(("" + c).getBytes());
// }
// } else {
// out.write(("" + c).getBytes());
// }
out.write(("" + c).getBytes());
}
}
private static void translateObject(InputStreamReader re, OutputStream out) throws IOException, IllegalArgumentException {
char c;
String field = null;
while ((c = (char) re.read()) != EOFC) {
switch (c) {
case ':':
if (field != null) {
out.write("<".getBytes());
out.write(field.getBytes());
out.write(">".getBytes());
}
boolean eoo = translateValue(re, out, field);
if (field != null) {
out.write(".getBytes());
out.write(field.getBytes());
out.write(">".getBytes());
}
if (eoo) {
return;
}
break;
case '"':
field = readStringToken(re);
break;
case '}':
return;
default:
}
}
}
/**
* 遍历元素
*
* @param node 元素
* @param json 将元素遍历完成之后放进JSON对象
*/
private static void iterateNodes(Element node, JSONObject json, String parseArrayNames) {
//获取当前元素的名称
String nodeName = node.getName();
List<String> parseArrayNamesList = Arrays.asList(parseArrayNames.split(","));
//判断已遍历的JSON中是否已经有了该元素的名称
if (json.containsKey(nodeName) || parseArrayNamesList.contains(nodeName)) {
//该元素在同级下有多个
Object Object = json.get(nodeName);
JSONArray array = new JSONArray();
if (Object instanceof JSONArray) {
array = (JSONArray) Object;
} else if (Object != null) {
array = new JSONArray();
array.add(Object);
}
//获取该元素下所有子元素
List<Element> listElement = node.elements();
if (listElement.isEmpty()) {
//该元素无子元素，获取元素的值
String nodeValue = node.getTextTrim();
array.add(nodeValue);
json.put(nodeName, array);
return;
}
//有子元素
JSONObject newJson = new JSONObject();
//遍历所有子元素
for (Element e : listElement) {
//递归
iterateNodes(e, newJson, parseArrayNames);
}
array.add(newJson);
json.put(nodeName, array);
return;
}
//该元素同级下第一次遍历
//获取该元素下所有子元素
List<Element> listElement = node.elements();
if (listElement.isEmpty()) {
//该元素无子元素，获取元素的值
String nodeValue = node.getTextTrim();
json.put(nodeName, nodeValue);
return;
}
//有子节点，新建一个JSONObject来存储该节点下子节点的值
JSONObject object = new JSONObject();
//遍历所有一级子节点
for (Element e : listElement) {
//递归
iterateNodes(e, object, parseArrayNames);
}
json.put(nodeName, object);
return;
}
}
用法示例：
import net.sf.json.JSONObject;
import static com.java.JsonXmlUtil.getJsonFromXml;
import static com.java.JsonXmlUtil.getXmlFromJson;
public class MyTest3 {
public static void main(String[] args) throws Exception {
//json转xml
String jsonString = "{\"result\":{\"userList\":[{\"name\":\"zs\",\"age\":21},{\"name\":\"bb\",\"age\":35}]}}";
String xml = getXmlFromJson(jsonString);
System.out.println("输入的json为：");
System.out.println(jsonString);
System.out.println("输出的xml为：");
System.out.println(xml);
System.out.println("------------------------" + "分割线" + "------------------------");
//xml转json
String input_xml = "" +
"zs 21 bb 35 效果展示：
