数据库查询出记录封装到对象中

[漆黑之勺]

从一个数据库中查出5条数据,我想把这五条数据的每一条作为一个结果集封装到emp对象中,然后把对象封装到list中,代码怎么写,急用,在线等

[tengfeng05]

给你我写过的一个类参考。利用了java泛型和反射，使用前须创建好与该数据库表相应的pojo类，该javabean中的每个字段和你数据库中表的字段名字相同。直接继承该类即可，方法返回一个封装了该pojo的list集合

public class Query<T> {

	private DBUtil db = DBUtil.getInstance();

	private List<T> list = null;

	private int totleCount = -1;

	private Class<T> entityClass;

	private String sql = null;

	@SuppressWarnings("unchecked")
	public Query(String sql) {

		this.entityClass = (Class<T>) ((ParameterizedType) getClass()
				.getGenericSuperclass()).getActualTypeArguments()[0];
		this.sql = sql;
		this.list = excute(sql);
	}
	

		public int getCount() {

		return totleCount;
	}

	public List<T> getGridData(int start, int size) {

		if (start + size > totleCount) {
			size = totleCount - start;
		}
		return list.subList(start, start + size);

	}

	public List<T> getQueryData() {

		return list;
	}

	public List<T> excute(String sql) {

		ArrayList<T> list = null;
		Statement stm = db.getStatement(ResultSet.TYPE_SCROLL_INSENSITIVE,
				ResultSet.CONCUR_READ_ONLY);
		ResultSet rst = null;
		try {
			rst = stm.executeQuery(sql);
			rst.last();
			totleCount = rst.getRow();
			rst.beforeFirst();
			list = new ArrayList<T>(totleCount);
			while (rst.next()) {
				ResultSetMetaData metaData = rst.getMetaData();
				T t = entityClass.newInstance();
				for (int j = 1; j <= metaData.getColumnCount(); j++) {
					String name = metaData.getColumnName(j);
					try {
						Field field = entityClass.getDeclaredField(name
								.substring(0, 1).toLowerCase()
								+ name.substring(1));
						Method method = entityClass.getMethod("set"
								+ name.substring(0, 1).toUpperCase()
								+ name.substring(1), field.getType());
						String type = field.toGenericString();
						if (type.contains("java.lang.String")) {
							method.invoke(t, rst.getString(name));
						} else if (type.contains("java.lang.Integer")) {
							method.invoke(t, rst.getInt(name));
						} else if (type.contains("java.lang.Double")) {
							method.invoke(t, rst.getDouble(name));
						} else if (type.contains("java.sql.Date")) {
							method.invoke(t, rst.getDate(name));

						} else if (type.contains("java.sql.Timestamp")) {
							method.invoke(t, rst.getTimestamp(name));
						}
					} catch (NoSuchFieldException e) {
						/*
						 * System.out.println("找不到字段" + name.substring(0,
						 * 1).toLowerCase() + name.substring(1) + "，将忽略处理。");
						 */
					}

				}
				list.add(t);
			}

		} catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		} finally {
			db.freeResource(stm, rst);
		}
		return list;
	}

	}

[打油的程序员]

public class TestPeroson extends ArrayList<Person> {
    public static ArrayList<Person>  persons = new ArrayList<Person>();   
    public static void main(String args[]) {
	    init();
	    display();
    }
    public static void init(){
	    persons.add(new Person(1, "a", 11));
	    persons.add(new Person(2, "b", 11));
	    persons.add(new Person(3, "c", 11));
	    persons.add(new Person(4, "d", 11));
    }
    public static void display(){
	for(Person person:persons){
	    System.out.println(person.id + "  "  + person.name + " "   + person.age);
	}
    }   
}

class Person{
    int id ;String name; int  age;
    public Person(int id, String name, int age) {
	this.id = id;
	this.name = name;
	this.age = age;
    }
}
/*
1  a 11
2  b 11
3  c 11
4  d 11

*/

[打油的程序员]

五条数据贴出来
emp那个类也贴出来

[huntor]

使用每一行的字段创建一个emp，加到list。

[漆黑之勺]

数据:
id name age
1 a 11
2 b 11
3 c 11
4 d 11

我想要的是把这四条数据每一条作为一个对象(每一个对象封装了id,name,age),然后对象放入到一个list中

[lzliang0330]

List list = new List();
Emp e = new Emp();
e.setId(1);
e.setName(a);
e.setAge(11);
list.add(e);

当然set进去的值需要你自已从数据库里拉出来。

[huntor]

while(rs.next()){
list.add(new Emp(rs.getInt("id"),rs.getString("name"),rs.getInt("age"));
}

[漆黑之勺]

[Quote=引用 4 楼 lzliang0330 的回复:]
List list = new List();
Emp e = new Emp();
e.setId(1);
e.setName(a);
e.setAge(11);
list.add(e);

当然set进去的值需要你自已从数据库里拉出来。
[/Quote]貌似不对吧