自己动手实现mybatis动态sql的方法

发现要坚持写博客真的是一件很困难的事情，各种原因都会导致顾不上博客。本来打算写自己动手实现orm，看看时间，还是先实现一个动态sql，下次有时间再补上orm完整的实现吧。

用过mybatis的人，估计对动态sql都不陌生，如果没有用过，就当看看热闹吧。我第一次接触mysql是在大四的时候，当时就觉得动态sql这东西很牛，很灵活，一直想搞明白怎么实现的，尽管当时已经能够写ioc，mvc和简单的orm框架(仿mybaits但是没有动态sql部分)，但是仍然找不到mybatis核心的动态sql到底在哪实现的，怎么实现的，可能是那些代码太绕根本没法看懂，直到目前，我都没有勇气去看mybatis的动态sql部分，大概是天生对算法有莫名其妙的敬畏吧。

几年前因为想做一个配置平台，想用解析型语言替代java的实现，可以让配置人员在页面上方便的编写少量代码实现复杂的业务逻辑（包括数据库操作）。当时java已经有js解析引擎，但是大多数人都说效率太低，不知道我发什么疯就想到自己实现一个解析语言。不过实现自己的语言也是我一直的梦想，解析语言相对编译型语言入手简单，于是我就果断动手了，写完才知道，其实自己的实现估计还没有当时的js引擎效率高，那时的我真的是很年轻很简单。今天谈到的动态sql实现其实就是受到那时候解析语言的启发。

废话不多说直接开始聊动态sql，请看下面例子，先声明这里的例子并不是一个正确的sql的写法，只是想写一个尽量复杂的嵌套结构，如果把这种复杂的情况实现了，那么简单一点的就更加不在话下了。

delete from pl_pagewidget
<if test="widgetcodes != null">
where pagewidgetcode in
<foreach collection="widgetcodes" item="item" index="index" open="(" separator="," close=")">
<if test="index == 0">
#{item}
</if>
<foreach collection="bs" item="b" index="index1" open="(" separator="," close=")">
 #{b}
</foreach>
</foreach>
</if>
<if test="a != null">
and a = #{a}
</if>

要实现解析出上面例子的sql，首先一个难点类似是test属性里的条件怎么判断真假，不过这个难点在struts2中学到的ognl表达式面前就比较小儿科了。不知道有么有朋友遇到过一个比较奇葩的现象，就是有时候明明在mybatis动态sql中写如下表达式，但是当n=0的时候居然是满足条件的也就是test里的值是false，0居然不能满足这个表达式的条件，这里就是ognl库的原因了。没办法它就是这么玩的，当成特殊情况记住就可以了

test="n != null and n !=''"

ognl表达式使用很方便如下

import java.util.HashMap;
import java.util.Map;
import ognl.Ognl;
public class OgnlTest {
//输出结果:false
public static void main(String[] args) throws Exception {
String con1 = "n != null and n != ''";
Map<String,Object> root = new HashMap<>();
root.put("n", 0);
System.out.println(Ognl.getValue(con1,root));
}
}

要实现解析上面例子的sql，第二个难点就是虽然这个sql披上一层xml的皮就是一个标准的sql，如下

<sql>
delete from pl_pagewidget
<if test="widgetcodes != null">
where pagewidgetcode in
<foreach collection="widgetcodes" item="item" index="index" open="(" separator="," close=")">
<if test="index == 0">
#{item}
</if>
<foreach collection="bs" item="b" index="index1" open="(" separator="," close=")">
 #{b}
</foreach>
</foreach>
</if>
<if test="a != null">
and a = #{a}
</if>
</sql>

但是要解析上面的xml和我们平时不一样，这个xml是标签和文本混合的，正常我们开发中应该很少会用到解析这种xml。不过我们常用的解析xml的工具dom4j其实可以很好的解析这种sql，只不过很少可能用到。Element类的content()方法就可以返回一个Node的集合，再通过遍历这个集合，判断每个Node的类型就可以了。解决了这两个重点，只需要加上一点技巧就可以解析这种动态sql了。

我用到的技巧是根据java语法格式得到的启发。比如java中有局部变量和全局变量，不考虑引用传递这种情况，如果全局变量int i = 1；方法里面传入这个全局变量，然后在方法里面修改，在方法里面看到的是改变后的值，但是在方法外面看到的仍然是1。这个现象其实学过java应该都知道。还有就是当方法调用的时候，方法里面可以看到全局变量，也可以看到局部变量，方法调用结束后局部变量会被清空释放(看垃圾搜集器高兴)。介绍了这些直接上代码了

import java.io.StringReader;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.apache.commons.collections.MapUtils;
import org.apache.commons.lang.StringUtils;
import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.Node;
import org.dom4j.Text;
import org.dom4j.io.SAXReader;
import com.rd.sql.Attrs;
import com.rd.sql.BaseNode;
import com.rd.sql.NodeFactory;
public class SqlParser {
private Map<String,Object> currParams = new HashMap<String,Object>();

/**
delete from pl_pagewidget
<if test="widgetcodes != null">
 where pagewidgetcode in
 <foreach collection="widgetcodes" item="item" index="index" open="(" separator="," close=")">
 <if test="index == 0">
 #{item}
 </if>
 <foreach collection="bs" item="b" index="index1" open="(" separator="," close=")">
 #{b}
 </foreach>
 </foreach>
</if>
<if test="a != null">
 and a = #{a}
</if>
*/
public static void main(String[] args) throws Exception {
Map<String, Object> map = new HashMap<String, Object>();
map.put("widgetcodes", Arrays.asList("1", "2"));
map.put("bs", Arrays.asList("3", "4"));
map.put("a", 1);
SqlParser parser = new SqlParser();
System.out
 .println(parser.parser("delete from pl_pagewidget\n"
   + "\t<if test=\"widgetcodes != null\">\n"
   + "\t\twhere pagewidgetcode in\n"
   + "\t\t<foreach collection=\"widgetcodes\" item=\"item\" index=\"index\" open=\"(\" separator=\",\" close=\")\">\n"
   + "\t\t <if test=\"index == 0\">\n"
   + "\t\t #{item}\n"
   + "\t\t </if>\n"
   + "\t\t <foreach collection=\"bs\" item=\"b\" index=\"index1\" open=\"(\" separator=\",\" close=\")\">\n"
   + "\t\t\t#{b}\n" + "\t\t </foreach>\n"
   + "\t\t</foreach>\n" + "\t</if>\n"
   + "\t<if test=\"a != null\">\n"
   + "\t\tand a = #{a}\n" + "\t</if>\n", map));
System.out.println(parser.getParams());
}
public String parser(String xml, Map<String, Object> params)
 throws Exception {
// xml = "<?xml version=\"1.0\" encoding=\"UTF-8\"?>"+xml;
//给输入的动态sql套一层xml标签
xml = "<sql>"+xml+"</sql>";
SAXReader reader = new SAXReader(false);
Document document = reader.read(new StringReader(xml));
Element element = document.getRootElement();
Map<String, Object> currParams = new HashMap<String, Object>();
StringBuilder sb = new StringBuilder();
//开始解析
parserElement(element, currParams, params, sb);
return sb.toString();
}
/**
* 使用递归解析动态sql
* @param ele1 待解析的xml标签
* @param currParams
* @param globalParams
* @param sb
* @throws Exception
*/
private void parserElement(Element ele1, Map<String, Object> currParams,
 Map<String, Object> globalParams, StringBuilder sb)
 throws Exception {
// 解析一个节点，比如解析到了一个if节点，假如test判断为true这里就返回true
TempVal val = parserOneElement(currParams, globalParams, ele1, sb);
//得到解析的这个节点的抽象节点对象
BaseNode node = val.getNode();
/**
 * 实际上这句之上的语句只是解析了xml的标签，并没有解析标签里的内容，这里
 * 表示要解析内容之前，如果有前置操作做一点前置操作
 */
node.pre(currParams, globalParams, ele1, sb);
//判断是否还需要解析节点里的内容，例如if节点test结果为true
boolean flag = val.isContinue();
// 得到该节点下的所有子节点的集合，包含普通文本
List<Node> nodes = ele1.content();
if (flag && !nodes.isEmpty()) {
 /**
 * 这里表示要进一步解析节点里的内容了，可以把节点类比成一个方法的外壳
 * 里面的内容类比成方法里的具体语句，开始解析节点的内容之前
 * 先创建本节点下的局部参数的容器，最方便当然是map
 */
 Map<String, Object> params = new HashMap<String, Object>();
 /**
 * 把外面传进来的局部参数，直接放入容器，由于本例中参数都是常用数据类型
 * 不会存在引用类型所以，这里相当于是一个copy，为了不影响外面传入的对象
 * 可以类比方法调用传入参数的情况
 */
 params.putAll(currParams);
 //循环所有子节点
 for (int i = 0; i < nodes.size();) {
 Node n = nodes.get(i);
 //如果节点是普通文本
 if (n instanceof Text) {
  String text = ((Text) n).getStringValue();
  if (StringUtils.isNotEmpty(text.trim())) {
  //处理一下文本，如处理#{xx},直接替换${yy}为真实传入的值
  sb.append(handText(text, params,globalParams));
  }
  i++;
 } else if (n instanceof Element) {
  Element e1 = (Element) n;
  // 递归解析xml子元素
  parserElement(e1, params, globalParams, sb);
  // 如果循环标志不为true则解析下一个标签
  // 这里表示需要重复解析这个循环标签，则i不变,反之继续处理下一个元素
  boolean while_flag = MapUtils.getBoolean(params,
   Attrs.WHILE_FLAG, false);
  if (!while_flag
   || !NodeFactory.isWhile(n.getName())
   || e1.attributeValue(Attrs.INDEX) == null
   || !e1.attributeValue(Attrs.INDEX).equals(
    params.get(Attrs.WHILE_INDEX))) {
  i++;
  }
 }
 }
 //节点处理之后做一些啥事
 node.after(currParams, globalParams, ele1, sb);
 // 回收当前作用域参数
 params.clear();
 params = null;
}
}
/**
* 处理文本替换掉#{item}这种参数
* @param str
* @param params
* @return
* @throws Exception
*/
private String handText(String str, Map<String, Object> params,Map<String, Object> globalParams)
 throws Exception {
//获取foreach这种标签中用于记录循环的变量
String indexStr = MapUtils.getString(params, Attrs.WHILE_INDEX);
Integer index = null;
if(StringUtils.isNotEmpty(indexStr)) {
 index = MapUtils.getInteger(params, indexStr);
}
//匹配#{a}这种参数
String reg1 = "(#\\{)(\\w+)(\\})";
//匹配${a}这种参数
String reg2 = "(\\$\\{)(\\w+)(\\})";
Pattern p1 = Pattern.compile(reg1);
Matcher m1 = p1.matcher(str);
Pattern p2 = Pattern.compile(reg2);
Matcher m2 = p2.matcher(str);
String whileList = MapUtils.getString(params, Attrs.WHILE_LIST);
Map<String,Object> allParams = getAllParams(params, globalParams);
while(m1.find()) {
 String tmpKey = m1.group(2);
 String key = whileList == null?tmpKey:(whileList+"_"+tmpKey);
 key = index == null?key:(key+index);
 String reKey = "#{"+key+"}";
 //如果在foreach类似的循环里，可能需要将参数#{xx}替换成#{xx_0},#{xx_1}
 str = str.replace(m1.group(0), reKey);
 currParams.put(key, allParams.get(tmpKey));
}
while(m2.find()) {
 String tmpKey = m2.group(2);
 Object value = allParams.get(tmpKey);
 if(value != null) {
 str = str.replace(m2.group(0), getValue(value));
 }
}
return str;
}
private String getValue(Object value) {
String result = "";
if(value instanceof Date) {
 SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
 result = sdf.format((Date)value);
} else {
 result = String.valueOf(value);
}
return result;
}
private Map<String, Object> getAllParams(Map<String, Object> currParams,
 Map<String, Object> globalParams) {
Map<String,Object> allParams = new HashMap<String,Object>();
allParams.putAll(globalParams);
allParams.putAll(currParams);
return allParams;
}

// 解析一个xml元素
private TempVal parserOneElement(Map<String, Object> currParams,
 Map<String, Object> globalParams, Element ele, StringBuilder sb)
 throws Exception {
//获取xml标签名
String eleName = ele.getName();
//解析一个节点后是否继续，如遇到if这种节点，就需要判断test里是否为空
boolean isContinue = false;
//声明一个抽象节点
BaseNode node = null;
if (StringUtils.isNotEmpty(eleName)) {
 //使用节点工厂根据节点名得到一个节点对象比如是if节点还是foreach节点
 node = NodeFactory.create(eleName);
 //解析一下这个节点，返回是否还需要解析节点里的内容
 isContinue = node.parse(currParams, globalParams, ele, sb);
}
return new TempVal(isContinue, ele, node);
}
public Map<String, Object> getParams() {
return currParams;
}
/**
* 封装一个xml元素被解析后的结果
* @author rongdi
*/
final static class TempVal {
private boolean isContinue;
private Element ele;
private BaseNode node;
public TempVal(boolean isContinue, Element ele, BaseNode node) {
 this.isContinue = isContinue;
 this.ele = ele;
 this.node = node;
}
public boolean isContinue() {
 return isContinue;
}
public void setContinue(boolean isContinue) {
 this.isContinue = isContinue;
}
public Element getEle() {
 return ele;
}
public void setEle(Element ele) {
 this.ele = ele;
}
public BaseNode getNode() {
 return node;
}
public void setNode(BaseNode node) {
 this.node = node;
}
}
}

import org.dom4j.Element;
import java.util.HashMap;
import java.util.Map;
/**
* 抽象节点
* @author rongdi
*/
public abstract class BaseNode {
public abstract boolean parse(Map<String, Object> currParams, Map<String, Object> globalParams, Element ele,StringBuilder sb) throws Exception;
public void pre(Map<String, Object> currParams,Map<String, Object> globalParams,Element ele,StringBuilder sb) throws Exception {
}
public void after(Map<String, Object> currParams,Map<String, Object> globalParams,Element ele,StringBuilder sb) throws Exception {
}
protected Map<String, Object> getAllParams(Map<String, Object> currParams,
     Map<String, Object> globalParams) {
Map<String,Object> allParams = new HashMap<String,Object>();
allParams.putAll(globalParams);
allParams.putAll(currParams);
return allParams;
}
}

import java.util.Map;
import ognl.Ognl;
import org.apache.commons.lang.StringUtils;
import org.dom4j.Element;
/**
* if节点
* @author rongdi
*/
public class IfNode extends BaseNode{
@Override
public boolean parse(Map<String, Object> currParams, Map<String, Object> globalParams, Element ele,StringBuilder sb) throws Exception {
//得到if节点的test属性
String testStr = ele.attributeValue("test");
boolean test = false;
try {
 if(StringUtils.isNotEmpty(testStr)) {
 //合并全局变量和局部变量
 Map<String, Object> allParams = getAllParams(currParams,globalParams);
 //使用ognl判断true或者false
 test = (Boolean) Ognl.getValue(testStr,allParams);
 }
} catch (Exception e) {
 e.printStackTrace();
 throw new Exception("判断操作参数"+testStr+"不合法");
}
if(ele.content() != null && ele.content().size()==0) {
 test = true;
}
return test;
}
}

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import ognl.Ognl;
import org.apache.commons.collections.MapUtils;
import org.apache.commons.lang.StringUtils;
import org.dom4j.Element;
/**
foreach节点属性如下
collection 需要遍历的集合
item 遍历集合后每个元素存放的变量
index 遍历集合的索引数如0,1,2...
separator 遍历后以指定分隔符拼接
open 遍历后拼接开始的符号如 (
close 遍历后拼接结束的符号如 )
*/
public class ForeachNode extends BaseNode {
@Override
public boolean parse(Map<String, Object> currParams, Map<String, Object> globalParams, Element ele, StringBuilder sb) throws Exception {
String conditionStr = null;
String collectionStr = ele.attributeValue("collection");
String itemStr = ele.attributeValue("item");
String index = ele.attributeValue("index");
String separatorStr = ele.attributeValue("separator");
String openStr = ele.attributeValue("open");
String closeStr = ele.attributeValue("close");
if(StringUtils.isEmpty(index)) {
 index = "index";
}
if(StringUtils.isEmpty(separatorStr)) {
 separatorStr = ",";
}
if(StringUtils.isNotEmpty(openStr)) {
 currParams.put(Attrs.WHILE_OPEN,openStr);
}
if(StringUtils.isNotEmpty(closeStr)) {
 currParams.put(Attrs.WHILE_CLOSE,closeStr);
}
if(StringUtils.isNotEmpty(collectionStr)) {
 currParams.put(Attrs.WHILE_LIST,collectionStr);
}
currParams.put(Attrs.WHILE_SEPARATOR,separatorStr);
if(index != null) {
 /**
 * 如果局部变量中存在当前循环变量的值，就表示已经不是第一次进入循环标签了，移除掉开始标记
 * 并将局部变量值加1
 */
 if(currParams.get(index) != null) {
 currParams.remove(Attrs.WHILE_START);
 currParams.put(index+"_", (Integer)currParams.get(index+"_") + 1);
 } else { //第一次进入循环标签内
 currParams.put(Attrs.WHILE_START,true);
 currParams.put(index+"_", 0);
 }
 currParams.put(index, (Integer)currParams.get(index+"_"));
}
boolean condition = true;
Map<String, Object> allParams = getAllParams(currParams,globalParams);
Object collection = null;
if(StringUtils.isNotEmpty(collectionStr)) {
 //得到待循环的集合
 collection = Ognl.getValue(collectionStr,allParams);
 //如果集合属性不为空，但是条件为null则默认加上一个边界条件
 if(StringUtils.isEmpty(conditionStr)) {
 //这里只是用集合演示一下，也可以再加上数组，只不过改成.length而已
 if(collection instanceof List) {
  conditionStr = index+"_<"+collectionStr+".size()";
 } else if(collection instanceof Map){
  Map map = (Map)collection;
  Set set = map.entrySet();
  List list = new ArrayList(set);
  allParams.put("_list_", list);
  conditionStr = index+"_<_list_"+".size()";
 }
 }
}
currParams.remove(Attrs.WHILE_END);
if(StringUtils.isNotEmpty(conditionStr)) {
 //计算条件的值
 condition = (Boolean)Ognl.getValue(conditionStr,allParams);
 Map<String,Object> tempMap = new HashMap<>();
 tempMap.putAll(allParams);
 tempMap.put(index+"_",(Integer)currParams.get(index+"_") + 1);
 currParams.put(Attrs.WHILE_END,!(Boolean)Ognl.getValue(conditionStr,tempMap));
}
boolean flag = true;
currParams.put(Attrs.WHILE_INDEX, index);
currParams.put(Attrs.WHILE_FLAG, true);
if(condition) {
 try {
 if(StringUtils.isNotEmpty(itemStr) && StringUtils.isNotEmpty(collectionStr)) {
  Object value = null;
  int idx = Integer.parseInt(currParams.get(index+"_").toString());
  if(collection instanceof List) {
  value = ((List)collection).get(idx);
  currParams.put(itemStr, value);
  } else if(collection instanceof Map){
  Map map = (Map)collection;
  Set<Map.Entry<String,Object>> set = map.entrySet();
  List<Map.Entry<String,Object>> list = new ArrayList(set);
  currParams.put(itemStr, list.get(idx).getValue());
  currParams.put(index, list.get(idx).getKey());
  }
 }
 } catch (Exception e) {
 throw new Exception("从集合或者映射取值"+currParams.get(index)+"错误"+e.getMessage());
 }
} else {
 flag = false;
 destroyVars(currParams, index, itemStr);
}
return flag;
}
/**
* 如果是第一次进入循环标签，则拼上open的内容
*/
@Override
public void pre(Map<String, Object> currParams, Map<String, Object> globalParams, Element ele, StringBuilder sb) throws Exception {
super.pre(currParams, globalParams, ele, sb);
boolean start = MapUtils.getBoolean(currParams,Attrs.WHILE_START,false);
if(start) {
 String open = MapUtils.getString(currParams,Attrs.WHILE_OPEN);
 sb.append(open);
}
}
/**
* 如果是最后进入循环标签，则最后拼上close的内容
*/
@Override
public void after(Map<String, Object> currParams, Map<String, Object> globalParams, Element ele, StringBuilder sb) throws Exception {
super.after(currParams, globalParams, ele, sb);
boolean end = MapUtils.getBoolean(currParams,Attrs.WHILE_END,false);
String separator = MapUtils.getString(currParams,Attrs.WHILE_SEPARATOR);
if(!end && StringUtils.isNotEmpty(separator)) {
 sb.append(separator);
}
if(end) {
 String close = MapUtils.getString(currParams,Attrs.WHILE_CLOSE);
 if(sb.toString().endsWith(separator)) {
 sb.deleteCharAt(sb.length() - 1);
 }
 sb.append(close);
}
}
//释放临时变量
private void destroyVars(Map<String, Object> currParams, String index,String varStr) {
currParams.remove(Attrs.WHILE_INDEX);
currParams.remove(Attrs.WHILE_FLAG);
currParams.remove(Attrs.WHILE_SEPARATOR);
currParams.remove(Attrs.WHILE_START);
currParams.remove(Attrs.WHILE_END);
currParams.remove(Attrs.WHILE_LIST);
}
}

import org.dom4j.Element;
import java.util.Map;
public class SqlNode extends BaseNode{
@Override
public boolean parse(Map<String, Object> currParams, Map<String, Object> globalParams, Element ele,StringBuilder sb) throws Exception {
return true;
}
}

import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
/**
* 节点工厂
*/
public class NodeFactory {

private static Map<String,BaseNode> nodeMap = new ConcurrentHashMap<String,BaseNode>();
private final static List<String> whileList = Arrays.asList("foreach");
static {
nodeMap.put("if", new IfNode());
nodeMap.put("sql", new SqlNode());
nodeMap.put("foreach", new ForeachNode());
}
public static boolean isWhile(String elementName) {
return whileList.contains(elementName);
}
public static void addNode(String nodeName,BaseNode node) {

nodeMap.put(nodeName, node);

}

public static BaseNode create(String nodeName) {

return nodeMap.get(nodeName);

}

}

/**
* 各种标记
* @author rongdi
*/
public class Attrs {

public final static String TRANSACTIONAL = "transactional";
public final static String WHILE_START = "while-start";
public final static String WHILE_END = "while-end";
public final static String WHILE_OPEN = "while-open";
public final static String WHILE_CLOSE = "while-close";
public final static String WHILE_SEPARATOR = "while-separator";
public final static String WHILE_INDEX = "while-index";

public final static String WHILE_FLAG = "while-flag";

public final static String WHILE_LIST = "while-list";

public final static String WHEN_FLAG = "when-flag";

public static final String PROCESS_VAR = "process-var";

public final static String RESULT_FLAG = "result-flag";

public final static String RETURN_FLAG = "return-flag";

public final static String CONSOLE_VAR= "console-var";

public final static String DO = "do";

public final static String INDEX = "index";

public final static String CONDITION = "condition";

public final static String NAME= "name";

public final static String VALUE= "value";
public static final String TYPE = "type";
public static final String FORMAT = "format";

public static final String IF = "if";

public static final String ELSE = "else";

public final static String FILE= "file";

public static final String DATE = "date";

public static final String NOW = "now";

public static final String DECIMAL = "decimal";

public static final String ID = "id";

public static final String PARAMS = "params";
public static final String TARGET = "target";
public static final String SINGLE = "single";

public static final String PAGING = "paging";
public static final String DESC = "desc";
public static final String BREAK = "break";

public static final String CONTINUE = "continue";

public static final String COLLECTION = "collection";
public static final String VAR = "var";

public static final String EXECUTOR = "executor-1";

public static final String ROLLBACK_FLAG = "rollback-flag";

public static final String SERVICE = "service";

public static final String REF = "ref";
public static final String BIZS = "bizs";
public static final String TITLES = "titles";

public static final String COLUMNS = "columns";

public static final String CURRUSER = "currUser";

public static final String CURRPERM = "currPerm";

public static final String TASK_EXECUTOR = "taskExecutor";
public static final String DELIMITER = "delimiter";
public static final String OPERNAME = "operName";

}

currParams.remove(varStr);
currParams.remove(index);
currParams.remove(index+"_");
}
}

附上pom文件

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.rd</groupId>
<artifactId>parser</artifactId>
<packaging>jar</packaging>
<version>1.0-SNAPSHOT</version>
<name>myparser</name>
<url>http://maven.apache.org</url>
<dependencies>
<dependency>
 <groupId>dom4j</groupId>
 <artifactId>dom4j</artifactId>
 <version>1.6.1</version>
</dependency>
<dependency>
 <groupId>opensymphony</groupId>
 <artifactId>ognl</artifactId>
 <version>2.6.11</version>
</dependency>
<dependency>
 <groupId>commons-collections</groupId>
 <artifactId>commons-collections</artifactId>
 <version>3.2.1</version>
</dependency>
<dependency>
 <groupId>commons-lang</groupId>
 <artifactId>commons-lang</artifactId>
 <version>2.6</version>
</dependency>
<dependency>
 <groupId>junit</groupId>
 <artifactId>junit</artifactId>
 <version>3.8.1</version>
 <scope>test</scope>
</dependency>
</dependencies>
<build>
<resources>
 <resource>
 <directory>src/main/java</directory>
 <includes>
  <include>**/*.xml</include>
 </includes>
 </resource>
 <resource>
 <directory>src/main/resources</directory>
 <includes>
  <include>**/*</include>
 </includes>
 </resource>
</resources>
<testResources>
 <testResource>
 <directory>${project.basedir}/src/test/java</directory>
 </testResource>
 <testResource>
 <directory>${project.basedir}/src/test/resources</directory>
 </testResource>
</testResources>
<plugins>
 <plugin>
 <groupId>org.apache.maven.plugins</groupId>
 <artifactId>maven-compiler-plugin</artifactId>
 <version>3.1</version>
 <configuration>
  <source>1.8</source>
  <target>1.8</target>
  <encoding>UTF-8</encoding>
 </configuration>
 </plugin>
</plugins>
</build>
</project>

来源：http://www.cnblogs.com/rongdi/p/8013151.html