利用javabean技术封装对象

利用JavaBean技术读取文本内容并封装成对象：

（此方法可以演变为将 request中的参数，ResultSet中的数据，封装成对象）

javabean 规范：http://www.oracle.com/technetwork/java/javase/documentation/spec-136004.html

1 .要封装的对象：

public class User {

    private int id;

    private String name;

    private Integerage;

    public int getId() {

        returnid;

    }

    public void setId(int id) {

        this.id = id;

    }

    public String getName() {

        returnname;

    }

    public void setName(String name) {

        this.name = name;

    }

    public Integer getAge() {

        returnage;

    }

    public void setAge(Integer age) {

        this.age = age;

    }

}

 

2.读取文本的格式(id|name|age三个“属性”值，使用 |分割)：

user.txt

1 | Tom | 10

2 |jerry| 11

 

3．创建配置文件 user.property,内容如下(key 为类名 User ，值为 User的属性)：

User=id,name,age

 

4.利用Javabeanapi 操纵 User 对象， 并将文本内容封装成对象或对象集合

importjava.beans.PropertyDescriptor;

importjava.beans.PropertyEditor;

importjava.io.BufferedReader;

importjava.io.File;

importjava.io.FileInputStream;

importjava.io.IOException;

importjava.io.InputStream;

importjava.io.InputStreamReader;

importjava.lang.reflect.Method;

importjava.math.BigDecimal;

importjava.math.BigInteger;

importjava.util.ArrayList;

importjava.util.Arrays;

importjava.util.Date;

importjava.util.HashMap;

importjava.util.List;

importjava.util.Map;

importjava.util.Properties;

 

importcn.gov.cbrc.complaint.editors.CharacterEditor;

importcn.gov.cbrc.complaint.editors.CustomBooleanEditor;

importcn.gov.cbrc.complaint.editors.CustomNumberEditor;

importcn.gov.cbrc.complaint.editors.CustomDateEditor;

importcn.gov.cbrc.complaint.editors.CustomStringEditor;

 

public class ObjUtils {

   

    /**属性编辑器*/

    private static Map<Class<?>,PropertyEditor> defaultEditors ;

   

    static{

    defaultEditors=new HashMap<Class<?>, PropertyEditor>();

    defaultEditors.put(String.class,new CustomStringEditor());

    defaultEditors.put(int.class,new CustomNumberEditor(Integer.class,true));

    defaultEditors.put(Integer.class,new CustomNumberEditor(Integer.class,true));

    }  

    /**

     * 读取文件并组装对象

     * @param clazz 要封装的目标对象类型

     * @param propertiesPath存放对象属性名的properties文件

     * @param propKey存放对象属性名的properties文件的键

     * @param dataFilePath数据文件路径

     * @return

     */

    public static <T> List<T>convertDataFileToObj(Class<T> clazz,String propertiesPath ,StringpropKey,String dataFilePath){

        List<List<String>> values=readFileByLines(dataFilePath);

        List<String> propNames=getPropNames(propertiesPath,propKey);

        returnassembleEntity(clazz, propNames,values) ;

    }

   

    /**

     * 组装对象

     * @param clazz要封装的目标对象类型

     * @param propertyNames目标对象的属性名字集合

     * @param values将要赋给对象的属性值

     * @return

     */

    private static <T> List<T>assembleEntity(Class<T> clazz,List<String> propertyNames,List<List<String>> values){

        T entity=null;

        try {

            entity = clazz.newInstance();

        } catch (Exception e1) {

            e1.printStackTrace();

        }

        List<T> entities = new ArrayList<T>();

        for(List<String> rowValues : values){

            for(int i=0;i<rowValues.size();i++){

                PropertyDescriptor pd = null;

                try {

                    pd = new PropertyDescriptor(propertyNames.get(i),clazz);

                    Method m =pd.getWriteMethod();

                    PropertyEditor pe=defaultEditors.get(pd.getPropertyType());

                    pe.setAsText(rowValues.get(i));

                    m.invoke(entity,pe.getValue());

                } catch (Exception e) {

                    e.printStackTrace();

                }

            }

            entities.add(entity);

            try {

                entity=clazz.newInstance();

            } catch (Exception e){

                e.printStackTrace();

            }

    }

       

        return entities;

    }

   

 

    /**

     * 以行为单位读取文件

     */

    public static List<List<String>> readFileByLines(String filePath) {

        File file = new File(filePath);

        FileInputStream fis =null;

        InputStreamReader isr = null;

        BufferedReader reader = null;

        List<List<String>> values=new ArrayList<List<String>>();

        try {

        fis= new FileInputStream(file);

        isr=new InputStreamReader(fis,"utf-8");//指定以UTF-8编码读入

            System.out.println("以行为单位读取文件内容，一次读一整行：");

            reader = new BufferedReader(isr);

            String tempString = null;

            List<String> strs=null;

            // 一次读入一行，直到读入null为文件结束

            while ((tempString = reader.readLine()) !=null) {

                strs=Arrays.asList(tempString.split("\\|"));

                values.add(strs);

            }

            reader.close();

        } catch (IOException e) {

            e.printStackTrace();

        } finally {

            if (reader !=null) {

                try {

                    reader.close();

                } catch (IOException e1) {

                  e1.printStackTrace();

                }

            }

        }

        return values;

    }

   

//读取user.property 文件中所配置的属性名

    public static List<String> getPropNames(StringpropertiesPath,String key){

        Properties pro = new Properties();

        List<String> propNames=null;

        InputStream in=null;

        try {

            in = Thread.currentThread().getContextClassLoader().getResourceAsStream(propertiesPath);

            pro.load(in);

            propNames = Arrays.asList(pro.getProperty(key).split(","));

        } catch (Exception e) {

            e.printStackTrace();

        }finally{

            try {

                in.close();

            } catch (IOException e) {

                e.printStackTrace();

            }

        }

        return propNames;

    }

   

}

 

5.自定义属性编辑器写法：CustomStringEditor 用于将字符串转换成各种数据类型

 

importjava.beans.PropertyEditorSupport;

 

public class CustomStringEditor extends PropertyEditorSupport {

    public void setAsText(String text) throws IllegalArgumentException {

        super.setValue(text);

    }

}