Digester是apache的一个xml解析工具。
最近研究struts1源码时候才发现这东西挺好用的，可以很轻松的把XML转化成java对象。
上代码
public class Acptrule {
private String id;
private List<Rule> rules=new ArrayList<Rule>();
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public List<Rule> getRules() {
return rules;
}
public void setRules(List<Rule> rules) {
this.rules = rules;
}
public void addRule(Rule r){
rules.add(r);
}
public String toString(){
return "Acptrule:[id="+id+",\nrules:"+rules+"\n]";
}
}
public class Rule {
private String type;
private List<Round> rounds=new ArrayList<Round>();
public String getType() {
return type;
}
public void setType(String type) {
this.type = type;
}
public List<Round> getRounds() {
return rounds;
}
public void setRounds(List<Round> rounds) {
this.rounds = rounds;
}
public void addRound(Round r){
rounds.add(r);
}
public String toString(){
return "Rule:[type="+type+",\nrounds:"+rounds+"\n]";
}
}
public class Round {
private String val;
private String allowed;
private List<Noteinfo> notes=new ArrayList<Noteinfo>();
public String getVal() {
return val;
}
public void setVal(String val) {
this.val = val;
}
public String getAllowed() {
return allowed;
}
public void setAllowed(String allowed) {
this.allowed = allowed;
}
public List<Noteinfo> getNotes() {
return notes;
}
public void setNotes(List<Noteinfo> notes) {
this.notes = notes;
}
public void addNoteinfo(Noteinfo i){
notes.add(i);
}
public String toString(){
return "Round:[val="+val+",allowed="+allowed+",\nnotes:"+notes+"\n]";
}
}
public class Noteinfo {
private String notetype;
private String dcflag;
public String getNotetype() {
return notetype;
}
public void setNotetype(String notetype) {
this.notetype = notetype;
}
public String getDcflag() {
return dcflag;
}
public void setDcflag(String dcflag) {
this.dcflag = dcflag;
}
public String toString(){
return "Noteinfo:[notetype="+notetype+",dcflag="+dcflag+"]";
}
}以上是定义的几个java类。
下面是XML文件
<?xml version='1.0' encoding='gb18030'?> <acptrule id='20000000'> <rule type='C'> <round val='0' allowed='N'> <noteinfo type='02' dcflag='1' /> <noteinfo type='05' dcflag='1' /> <noteinfo type='10' dcflag='1' /> <noteinfo type='11' dcflag='1' /> <noteinfo type='19' dcflag='1' /> <noteinfo type='27' dcflag='1' /> <noteinfo type='31' dcflag='1' /> <noteinfo type='32' dcflag='1' /> <noteinfo type='33' dcflag='1' /> <noteinfo type='34' dcflag='1' /> <noteinfo type='72' dcflag='1' /> <noteinfo type='74' dcflag='1' /> </round> </rule> </acptrule>
解析代码
public static void main(String[] args) throws SQLException, IOException,
SAXException {
//读文件
URL url=Test.class.getClassLoader().getResource("20000.xml");
BufferedReader br = new BufferedReader(new FileReader(url.getPath()));
String line=null;
StringBuffer xml=new StringBuffer();
while((line=br.readLine())!=null){
xml.append(line);
}
//getRuleFromXML解析方法
Acptrule r = (Acptrule) getRuleFromXML(xml.toString());
System.out.println(r);
br.close();
}
//Digester解析
public static Acptrule getRuleFromXML(String xml) throws IOException,
SAXException {
Digester d = new Digester();
//不校验
d.setValidating(false);
//主要是通过RuleSet来做解析，网上大部分资料都是调用Degister.addXXX方法来实现的
//RuleSet相当于一个Rule的集合。在addRuleInstances方法里，可以自己设计各种Rule，实际上效果和addXXX相当。好处就是把Rule和某个Digester分离
RuleSet rs = new RuleSet() {
@Override
public String getNamespaceURI() {
return null;
}
@Override
public void addRuleInstances(Digester d) {
//对象创建Rule
d.addRule("acptrule", new ObjectCreateRule(Acptrule.class));
d.addRule("acptrule/rule", new ObjectCreateRule(Rule.class));
d.addRule("acptrule/rule/round", new ObjectCreateRule(Round.class));
d.addRule("acptrule/rule/round/noteinfo", new ObjectCreateRule(
Noteinfo.class));
//当解析acptrule/rule完成后，调用xx方法的rule
d.addRule("acptrule/rule", new SetNextRule("addRule"));
d.addRule("acptrule/rule/round", new SetNextRule("addRound"));
d.addRule("acptrule/rule/round/noteinfo", new SetNextRule(
"addNoteinfo"));
//属性赋值rule（标签的attribute）
d.addRule("acptrule", new SetPropertiesRule("id", "id"));
d.addRule("acptrule/rule",new SetPropertiesRule("type", "type"));
d.addRule("acptrule/rule/round", new SetPropertiesRule("val",
"val"));
d.addRule("acptrule/rule/round", new SetPropertiesRule(
"allowed", "allowed"));
d.addRule("acptrule/rule/round/noteinfo",
new SetPropertiesRule("type", "notetype"));
d.addRule("acptrule/rule/round/noteinfo",
new SetPropertiesRule("dcflag", "dcflag"));
}
};
d.addRuleSet(rs);
return (Acptrule) d.parse(new StringReader(xml));
}
