XStream 學習筆記

使用 Xstream 可以幫助我們完成繁瑣的 xml 和 JavaBean 之間的轉換。

gradle 依賴：

compile 'com.thoughtworks.xstream:xstream:1.4.8'
compile 'dom4j:dom4j:1.6.1'           

首先來看一個非常簡單的例子：

例1：

@Test
public void test01(){
    // 1、建立 XStream 對象
    XStream xStream = new XStream();
    // 2、設定别名（預設使用的是包名，可以使用 alias 将包名改寫成指定的名字）
    xStream.alias("person",Person.class);
    // 3、建立對象
    Person p = new Person("liwei","123456",28,14.19);
    // 4、轉換成 xml
    String xml = xStream.toXML(p);
    System.out.println(xml);
}           

輸出結果：

<person>
  <username>liwei</username>
  <password>123456</password>
  <age>28</age>
  <price>14.19</price>
</person>           

例2：

/**
 * 更改其中的屬性名稱
 */
@Test
public void test02(){
    // 1、建立 XStream 對象
    XStream xStream = new XStream();
    // 2、設定别名（預設使用的是包名，可以使用 alias 将包名改寫成指定的名字）
    xStream.alias("person",Person.class);
    // 改屬性名，類的屬性名是 username，生成的 xml 子節點名字改成 nickname（一般不用）
    xStream.aliasField("nickname",Person.class,"username");
    // 3、建立對象
    Person p = new Person("liwei","123456",28,14.19);
    // 4、轉換成 xml
    String xml = xStream.toXML(p);
    System.out.println(xml);
}           

<person>
  <nickname>liwei</nickname>
  <password>123456</password>
  <age>28</age>
  <price>14.19</price>
</person>           

例3：

/**
 * 把某個子節點改成屬性名
 * 把 password 屬性輸出的時候從 xml 子節點變成 xml 屬性
 */
@Test
public void test03(){
    // 1、建立 XStream 對象
    XStream xStream = new XStream();
    // 2、設定别名（預設使用的是包名，可以使用 alias 将包名改寫成指定的名字）
    xStream.alias("person",Person.class);
    // 改屬性名，類的屬性名是 username，生成的 xml 子節點名字改成 nickname（一般不用）
    xStream.aliasField("nickname",Person.class,"username");
    xStream.useAttributeFor(Person.class,"password");
    // 3、建立對象
    Person p = new Person("liwei","123456",28,14.19);
    // 4、轉換成 xml
    String xml = xStream.toXML(p);
    System.out.println(xml);
}           

<person password="123456">
  <nickname>liwei</nickname>
  <age>28</age>
  <price>14.19</price>
</person>           

例4：

@Test
public void test04(){
    XStream xStream = new XStream();
    xStream.alias("person",Person.class);
    xStream.alias("persons",List.class);
    List<Person> personList = new ArrayList<>();
    Person p1 = new Person("liwei","123456",28,14.19,new Group(1,"研發部"));
    Person p2 = new Person("zhouguang","666666",28,25.26,new Group(2,"交通大學"));
    Person p3 = new Person("huzhenyu","88888",23,16.18,new Group(3,"系統工程"));
    Person p4 = new Person("wudi","9999",25,18.14,new Group(4,"自營公司"));
    personList.add(p1);
    personList.add(p2);
    personList.add(p3);
    personList.add(p4);
    String xml = xStream.toXML(personList);
    System.out.println(xml);
}           

例5：

/**
 * 須要牢牢記住一點，xml 一定要有根節點，并且隻能有一個根節點
 */
@Test
public void test05(){
    XStream xStream = new XStream();
    xStream.alias("person",Person.class);
    xStream.alias("persons",List.class);
    // xStream.addImplicitCollection(Person.class,"List");
    List<Person> personList = new ArrayList<>();
    Person p1 = new Person("liwei","123456",28,14.19,new Group(1,"研發部"));
    Person p2 = new Person("zhouguang","666666",28,25.26,new Group(2,"交通大學"));
    Person p3 = new Person("huzhenyu","88888",23,16.18,new Group(3,"系統工程"));
    Person p4 = new Person("wudi","9999",25,18.14,new Group(4,"自營公司"));
    personList.add(p1);
    personList.add(p2);
    personList.add(p3);
    personList.add(p4);
    String xml = xStream.toXML(personList);
    System.out.println(xml);
}           

例6：

@Test
public void test06(){
    XStream xStream = new XStream();
    xStream.alias("group",Group.class);
    xStream.alias("person",Person.class);
    xStream.addImplicitCollection(Group.class,"personList");
    Group group = new Group(1,"研發部");
    Person p1 = new Person("liwei","123456",28,14.19,new Group(1,"研發部"));
    Person p2 = new Person("zhouguang","666666",28,25.26,new Group(2,"交通大學"));
    Person p3 = new Person("huzhenyu","88888",23,16.18,new Group(3,"系統工程"));
    Person p4 = new Person("wudi","9999",25,18.14,new Group(4,"自營公司"));
    group.addPerson(p1);
    group.addPerson(p2);
    group.addPerson(p3);
    group.addPerson(p4);
    String xml = xStream.toXML(group);
    System.out.println(xml);
}           

<group>
  <id>1</id>
  <name>研發部</name>
  <person>
    <username>liwei</username>
    <password>123456</password>
    <age>28</age>
    <price>14.19</price>
    <group>
      <id>1</id>
      <name>研發部</name>
    </group>
  </person>
  <person>
    <username>zhouguang</username>
    <password>666666</password>
    <age>28</age>
    <price>25.26</price>
    <group>
      <id>2</id>
      <name>交通大學</name>
    </group>
  </person>
  <person>
    <username>huzhenyu</username>
    <password>88888</password>
    <age>23</age>
    <price>16.18</price>
    <group>
      <id>3</id>
      <name>系統工程</name>
    </group>
  </person>
  <person>
    <username>wudi</username>
    <password>9999</password>
    <age>25</age>
    <price>18.14</price>
    <group>
      <id>4</id>
      <name>自營公司</name>
    </group>
  </person>
</group>           

/**
 * 把 XML 檔案片段轉換成 對象
 */
@Test
public void test07(){
    XStream xStream = new XStream();
    xStream.alias("person",Person.class);
    String xml = "<person><username>liwei</username><password>123456</password></person>";
    Person person = (Person) xStream.fromXML(xml);
    System.out.println(person.getUsername());
    System.out.println(person.getPassword());
}           

@Test
public void test08(){
    XStream xStream = new XStream();
    xStream.alias("persons",List.class);
    xStream.alias("person",Person.class);
    List<Person> personList =
            (List<Person>)xStream.fromXML(XstreamTest.class.getClassLoader().getResourceAsStream("user.xml"));
    for(Person person:personList){
        System.out.println(person);
    }
}