java 小测试

　写一个小小的工具类，根据bean的定义，从JDBC返回的ResultSet中装载相应的属性，如果ResultSet中没有对应的字段，设置为0、false、null、'0'等值。
　　bean可为用户自定义的任意bean，如
public class User {
    private String name;
    private Integer id;
    private int age;
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Integer getId() {
        return id;
    }
    public void setId(Integer id) {
        this.id = id;
    }
    public int getAge() {
        return age;
    }
    public void setAge(int age) {
        this.age = age;
    }
}
 


答案:
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class BeanUtil {
    public static Object load(java.sql.ResultSet rs, Object bean) {

    return getObject(rs,bean);
    
    }

    public static Object load(java.sql.ResultSet rs, Class cls) {
    Object bean=null;
try {
bean = cls.newInstance();

} catch (InstantiationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
};

        return getObject(rs,bean);
    }
   
   
    private static Object getObject(ResultSet rs,Object bean){
    try {
while(rs.next()){
Field[] fields=bean.getClass().getDeclaredFields();   
for(int i=0;i<fields.length;i++){
        Field field=fields[i];
        String fieldName=field.getName();
        String t="set"+fieldName.substring(0,1).toUpperCase()+fieldName.substring(1);
        Method method=bean.getClass().getMethod(t,field.getType());
        String temp=field.getType().getName();
        if(temp.equals("java.lang.String")){
        method.invoke(bean, rs.getString(fieldName));
        }            
           
        if(temp.equals("java.lang.Integer") || temp.equals("int")){
       
        method.invoke(bean, rs.getInt(fieldName));
        }
     }


} 
} catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SecurityException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (NoSuchMethodException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (InvocationTargetException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return bean;
    }
    public static void main(String args[]){
   
   
   
    User user=new User();
   
     

      try {
  Class.forName("oracle.jdbc.driver.OracleDriver");
  Connection con =DriverManager.getConnection("jdbc:oracle:thin:@localhost:1521:HOSPITAL", "hospital","hospital");
  Statement stm= con.createStatement();
  ResultSet rs = stm.executeQuery("select * from tuser");
  user=(User)BeanUtil.load(rs, user);
 
  System.out.println(user.getName());
  System.out.println(user.getId());
  System.out.println(user.getAge());
} catch (ClassNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}catch (SQLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}       
   
    }
}