用XStream读取XML解析成javabean

今天要解析一个xml文件，想起很久以前看到过用xstream相互转换mxl 和 javabean很方便，就上网查了下，不过在解析的时候碰到了两个问题，现在想记录下来，方便自己以后使用，也能帮助碰到同样问题的同学们。

参考文章：

Xstream用法总结

xStream完美转换XML、JSON

xStream完美转换XML、JSON

xStream的jar下载地址：

下载

官方的示例很全，官方参考示例

打开

我为了省事，把所有jar都加到buildpath里

当我按搜到文章解析mxl时碰见了一下两个问题：

首先：对象中包含List，解析报错，如何解析

查了很多文章,demo都很简单，没有关于包含list的例子

找了很久才找到个例子

要先对包含有集合的那个对象声明一下

如下：

xstream.addImplicitCollection(Root.class, "parentList");

解析的时候它就知道这个属性是一个集合了

因为我的xml里的值都是属性值，当解析后发现所有的值都是null，全都没有映射上

我又开始搜索，搜出很多同样的一片文章，里面说到自己写一个converter类，把属性值一个一个映射到对应的类属性上，想了想这还不类死啊

还好有一个文章下面有评论，里面将到只要先前声明一下就可以了，试了下，真的可以了，所有的值都正确解析出来了

如下

xstream.useAttributeFor("subruleid", String.class);

下面就是我测试类和解析的xml

public class Root {
private List<Parent> parentList = new ArrayList<Parent>();
省略getter和setter
}

public class Parent {
private String id;
private String comgroup;
private String currency;
private String exchange;
private String stampduty;
List<Child> childList = new ArrayList<Child>();
省略getter和setter
}

public class Child {
private String subruleid;
private String v5label;
省略getter和setter
}

public class XstreamDemo {

public static void main(String args[]) {
XStream xstream = new XStream(new DomDriver());
xstream.alias("root", Root.class);
xstream.alias("rule", Parent.class);
xstream.useAttributeFor("id", String.class);
xstream.useAttributeFor("comgroup", String.class);
xstream.useAttributeFor("currency", String.class);
xstream.useAttributeFor("exchange", String.class);
xstream.useAttributeFor("stampduty", String.class);
xstream.addImplicitCollection(Root.class, "parentList");
xstream.alias("subrule", Child.class);
xstream.useAttributeFor("subruleid", String.class);
xstream.useAttributeFor("v5label", String.class);
xstream.addImplicitCollection(Parent.class, "childList");
try {
InputStream in = new FileInputStream(new File("c:/temp/rules.xml"));
Root root = (Root) xstream.fromXML(in);
} catch (Exception e) {
e.printStackTrace();
}
}
}

<root>
<rule id="1712" comgroup="T30" currency="USD" exchange="SETS" stampduty="IE">
<subrule subruleid="1410" v5label="label" />
<subrule subruleid="1411" v5label="label11" />
<subrule subruleid="1711" v5label="Stamp duty (IE)" />
</rule>
<rule id="849" comgroup="C15" currency="USD" exchange="NYSE" stampduty="n">
<subrule subruleid="846" v5label="label" />
<subrule subruleid="847" v5label="S50US1" />
</rule>
<rule id="776" comgroup="EXP" currency="USD" exchange="NYSE" stampduty="n">
<subrule subruleid="773" v5label="label2" />
<subrule subruleid="774" v5label="S50US1" />
</rule>
<rule id="1008" comgroup="S00" currency="USD" exchange="NYSE" stampduty="n">
<subrule subruleid="1005" v5label="label3" />
<subrule subruleid="1006" v5label="S00US1" />
</rule>
<rule id="703" comgroup="S10" currency="USD" exchange="NYSE" stampduty="n">
<subrule subruleid="700" v5label="4" />
<subrule subruleid="701" v5label="S50US1" />
</rule>
<rule id="630" comgroup="S15" currency="USD" exchange="NYSE" stampduty="n">
<subrule subruleid="627" v5label="5" />
<subrule subruleid="628" v5label="S50US1" />
</rule>
<rule id="557" comgroup="S18" currency="USD" exchange="NYSE" stampduty="n">
<subrule subruleid="554" v5label="label6" />
<subrule subruleid="555" v5label="S50US1" />
</rule>
<rule id="484" comgroup="S20" currency="USD" exchange="NYSE" stampduty="n">
<subrule subruleid="481" v5label="label7" />
<subrule subruleid="482" v5label="S50US1" />
</rule>
<rule id="411" comgroup="S25" currency="USD" exchange="NYSE" stampduty="n">
<subrule subruleid="408" v5label="label8" />
<subrule subruleid="409" v5label="S50US1" />
</rule>
<rule id="338" comgroup="S30" currency="USD" exchange="NYSE" stampduty="n">
<subrule subruleid="335" v5label="label9" />
<subrule subruleid="336" v5label="S50US1" />
</rule>
<rule id="265" comgroup="SPC" currency="USD" exchange="NYSE" stampduty="n">
<subrule subruleid="262" v5label="labellabel10" />
<subrule subruleid="263" v5label="S50US1" />
</rule>
<rule id="935" comgroup="T30" currency="USD" exchange="NYSE" stampduty="n">
<subrule subruleid="932" v5label="label11" />
<subrule subruleid="933" v5label="P01US1" />
</rule>
</root>