Beanutils (1)

王朝java/jsp·作者佚名  2006-01-10
窄屏简体版  字體: |||超大  

PropertyUtils类:负责对Bean的重新设置和更改,支持3种属性,Simple ,Indexed ,Mapped 。

Simple:

Employee employee = ...;

String firstName = (String)

PropertyUtils.getSimpleProperty(employee, "firstName");

String lastName = (String)

PropertyUtils.getSimpleProperty(employee, "lastName");

... manipulate the values ...

PropertyUtils.setSimpleProperty(employee, "firstName", firstName);

PropertyUtils.setSimpleProperty(employee, "lastName", lastName);

Indexed:

Employee employee = ...;

int index = ...;

String name = "subordinate[" + index + "]";

Employee subordinate = (Employee)

PropertyUtils.getIndexedProperty(employee, name);

Employee employee = ...;

int index = ...;

Employee subordinate = (Employee)

PropertyUtils.getIndexedProperty(employee, "subordinate", index);

Indexed支持2种写法,一种直接指定属性名以及Index,还有一种是把两这分别赋值,符号是方括号[]。

Mapped:

Employee employee = ...;

Address address = ...;

PropertyUtils.setMappedProperty(employee, "address(home)", address);

Employee employee = ...;

Address address = ...;

PropertyUtils.setMappedProperty(employee, "address", "home", address);

Mapped也支持2种写法,和Indexed不同的是他用的是Key,不是Index,符号是圆括号()。

同时它还支持属性的嵌套:

String city = employee.getAddress("home").getCity();

等价于

String city = (String)PropertyUtils.getNestedProperty(employee, "address(home).city");

以及以上情况的任意结合:

Employee employee = ...;

String city = (String) PropertyUtils.getProperty(employee,

"subordinate[3].address(home).city");

Dynamic Beans:最基本的接口是DynaBean和DynaClass。DynaBean负责生成动态的Bean,而DynaClass则是生成动态的Class。

BasicDynaBean和BasicDynaClass类

DynaProperty[] props = new DynaProperty[]{

new DynaProperty("address", java.util.Map.class),

new DynaProperty("subordinate", mypackage.Employee[].class),

new DynaProperty("firstName", String.class),

new DynaProperty("lastName", String.class)

};

BasicDynaClass dynaClass = new BasicDynaClass("employee", null, props);

ResultSetDynaClass类

Connection conn = ...;

Statement stmt = conn.createStatement();

ResultSet rs = stmt.executeQuery

("select account_id, name from customers");

Iterator rows = (new ResultSetDynaClass(rs)).iterator();

while (rows.hasNext()) {

DynaBean row = (DynaBean) rows.next();

System.out.println("Account number is " +

row.get("account_id") +

" and name is " + row.get("name"));

}

rs.close();

stmt.close();

但是ResultSetDynaClass是一定要在资源打开的情况下才能使用。

RowSetDynaClass 类

Connection conn = ...; // Acquire connection from pool

Statement stmt = conn.createStatement();

ResultSet rs = stmt.executeQuery("SELECT ...");

RowSetDynaClass rsdc = new RowSetDynaClass(rs);

rs.close();

stmt.close();

...; // Return connection to pool

List rows = rsdc.getRows();

...; // Process the rows as desired

RowSetDynaClass 就不象ResultSetDynaClass,需要都打开,但是他占用更多的内存。

 
 
 
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