Java中Bean与Map/Json/DBObject的相互转换

1.JavaBean

 

public class Person {

    private String name;
    private Integer age;
    private String job;
    private List<String> school;
    private String address;
    private List<Score> score;
    //省略get/set方法
}

 

public class Score {

    private String cource_name;
    private Integer cource_score;
    //省略get/set方法
}

2.JavaBean与Map相互转换（使用Apache Commons的BeanUtil实现）

 

 

       //Map<String,Object>转成JavaBean
//测试已通过，Bean中包含另一个Bean成员也可以
public static Object transMap2Bean(Map<String, Object> map, Object obj) {
    if (map == null || obj == null) {
        return null;BeanUtils
    }
    try {
        BeanUtils.populate(obj, map);
    } catch (Exception e) {
        e.printStackTrace();
        return null;
    }
    return obj;
}

//JavaBean转成Map<String,Object>
//测试已通过，Bean中包含另一个Bean成员也可以
public static Map<String, Object> transBean2Map(Object obj) {

    if (obj == null) {
        return null;
    }
    Map<String, Object> map = new HashMap<String, Object>();
    try {
        BeanInfo beanInfo = Introspector.getBeanInfo(obj.getClass());
        PropertyDescriptor[] propertyDescriptors = beanInfo
                .getPropertyDescriptors();
        for (PropertyDescriptor property : propertyDescriptors) {
            String key = property.getName();

            // 过滤class属性
            if (!key.equals("class")) {
                // 得到property对应的getter方法
                Method getter = property.getReadMethod();
                Object value = getter.invoke(obj);

                map.put(key, value);
            }

        }
    } catch (Exception e) {
        e.printStackTrace();
        return null;
    }

    return map;

}

3.JavaBean与Json相互转换（使用JSONObject实现，需要导入json-lib.jar）

 

 

       //json字符串转成JavaBean
//测试已通过
@SuppressWarnings("unchecked")
public static <T> T json2Bean(String jsonString, Class<T> beanCalss) {
           JSONObject jsonObject = JSONObject.fromObject(jsonString);
           T bean = (T) JSONObject.toBean(jsonObject, beanCalss);

           return bean;
       }

//JavaBean转成json字符串
//测试已通过
public static String beanToJson(Object bean) {
           JSONObject json = JSONObject.fromObject(bean);
           return json.toString();
   }

4.JavaBean与DBObject相互转换（DBObject是MongoDB在Java驱动是使用的类）

 

 

       //DBObject转换成JavaBean
//测试已通过
public static <T> T dbObject2Bean(DBObject dbObject, T bean) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException {
           if (bean == null) {  //测试已通过
               return null;
           }
           Field[] fields = bean.getClass().getDeclaredFields();
           for (Field field : fields) {
               String varName = field.getName();
               Object object = dbObject.get(varName);
               if (object != null) {
                   BeanUtils.setProperty(bean, varName, object);
               }
           }
           return bean;
       }

       @SuppressWarnings("unchecked")
public static <T> DBObject bean2DBObject(T bean) throws IllegalArgumentException, IllegalAccessException {
    if (bean == null) {
        return null;
    }
    DBObject dbObject = new BasicDBObject();
    // 获取对象对应类中的所有属性域
    Field[] fields = bean.getClass().getDeclaredFields();
    for (Field field : fields) {
        // 获取属性名
        String varName = field.getName();
        // 修改访问控制权限
        boolean accessFlag = field.isAccessible();
        if (!accessFlag) {
            field.setAccessible(true);
        }
        Object param = field.get(bean);
        if (param == null) {
            continue;
        } else if (param instanceof Integer) {// 判断变量的类型
            int value = ((Integer) param).intValue();
            dbObject.put(varName, value);
        } else if (param instanceof String) {
            String value = (String) param;
            dbObject.put(varName, value);
        } else if (param instanceof Double) {
            double value = ((Double) param).doubleValue();
            dbObject.put(varName, value);
        } else if (param instanceof Float) {
            float value = ((Float) param).floatValue();
            dbObject.put(varName, value);
        } else if (param instanceof Long) {
            long value = ((Long) param).longValue();
            dbObject.put(varName, value);
        } else if (param instanceof Boolean) {
            boolean value = ((Boolean) param).booleanValue();
            dbObject.put(varName, value);
        } else if (param instanceof Date) {
            Date value = (Date) param;
            dbObject.put(varName, value);
        } else if (param instanceof List) {
            List<Object> list = (List<Object>) param;
            dbObject.put(varName, list);
        } else if (param instanceof Map) {
            Map<Object, Object> map = (Map<Object, Object>) param;
            dbObject.put(varName, map);
        }
        // 恢复访问控制权限
        field.setAccessible(accessFlag);
    }
    return dbObject;
}

 

5.测试代码

package test;

import java.lang.reflect.InvocationTargetException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import org.junit.Before;
import org.junit.Test;

import com.mongodb.BasicDBObject;
import com.mongodb.DBObject;
import com.zmy.bean.Person;
import com.zmy.bean.Score;
import com.zmy.util.BeanUtil;
import com.zmy.util.DBObjectUtil;

public class ConvertTest {

    private Person person = null;
    private Map<String, Object> map = null;

    @Before
    public void initBean(){
        person = new Person();
        Score score1 = new Score();
        Score score2 = new Score();
        person.setAddress("大连");
        person.setAge(21);
        person.setJob("coder");
        person.setName("zmy");
        List<String> schools = new ArrayList<String>();
        List<Score> scores = new ArrayList<Score>();
        schools.add("DLUT");
        score1.setCource_name("course1");
        score1.setCource_score(85);
        score2.setCource_name("course2");
        score2.setCource_score(80);
        scores.add(score1);
        scores.add(score2);
        person.setSchool(schools);
        person.setScore(scores);
    }

    @Before
    public void initMap(){
        map = new HashMap<String, Object>();
        map.put("address", "大连");
        map.put("name", "zmy");
        map.put("job", "coder");
        map.put("age", 21);
        List<String> schools = new ArrayList<String>();
        schools.add("DLUT");
        schools.add("HUK");
        map.put("school", schools);
        List<Score> scores = new ArrayList<Score>();
        Score score1 = new Score();
        Score score2 = new Score();
        score1.setCource_name("course1");
        score1.setCource_score(85);
        score2.setCource_name("course2");
        score2.setCource_score(80);
        scores.add(score1);
        scores.add(score2);
        map.put("score", scores);
    }

    @Test
    public void testBean2Map(){
        Map<String, Object> map = BeanUtil.transBean2Map(person);
        System.out.println(map.toString());
    }

    @Test
    public void testMap2Bean(){
        Person person = (Person) BeanUtil.transMap2Bean(map, new Person());
        System.out.println(person.getName());
    }

    @Test
    public void testBean2Json(){
        String json = BeanUtil.beanToJson(person);
        System.out.println(json);

        Person person2 = BeanUtil.json2Bean(json, Person.class);
        System.out.println(person2.getName());
    }

    @Test
    public void testDBObject2Bean(){
        DBObject dbObject = new BasicDBObject(map);
        try {
            Person p = BeanUtil.dbObject2Bean(dbObject, new Person());
            System.out.println(p.getName());
        } catch (IllegalAccessException | InvocationTargetException
                | NoSuchMethodException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            System.out.println("转换error!!!");
        }

    }

    @Test
    public void testBean2DBObject(){
        try {
            DBObject dbObject = DBObjectUtil.bean2DBObject(person);
            System.out.println(dbObject.get("score"));
            System.out.println(person.getScore());
        } catch (IllegalArgumentException | IllegalAccessException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            System.out.println("转换error!!!");
        }
    }
}