Java的檢索sqlite的返回數據對象而不是值

Question

我想從我的數據庫獲取一些數據（我使用SQLite）使用DAO

public class ClassSectionDAO implements IClassSectionDAO{ 
    @Override 
    public void selectAllClassSection() { 
    d = new DBManager(); 
    sqliteQuery = new SqliteQueries(); 
    d.executeQuery(sqliteQuery.selectAllFrom("classSection")); 
    try{ 
     while(d.getResultSet().next()){ 
      ClassSection classSection = new ClassSection(); 
      classSection.setClassSectionId(d.getResultSet().getString("classSectionId")); 
      classSection.setSchoolClassCode(d.getResultSet().getString("schoolClassCode")); 
      classSection.setClassSectionNumber(d.getResultSet().getInt("classSectionNumber")); 
      classSection.setClassSectionAvailability(d.getResultSet().getString("classSectionAvailability")); 
      classSectionList.add(classSection); 
      System.out.println("classSectionList: " + classSectionList); 
     } 
    } 
    catch(Exception e){ 
     Logger.getLogger(ClassSectionDAO.class.getName()).log(Level.SEVERE, null, e); 
     classSectionList = null; 
    } 
    finally{ 
     d.closeDatabaseConnection(); 
    } 
    } 
} 

所有我得到的是對象的列表像

classSectionList: [entities.classSection.ClassSection@19ccf6d, entities.classSection.ClassSection@1faf0e7, entities.classSection.ClassSection@1cf8409] 

我應該怎麼做才能得到值呢？

PS：如果你想看到更多的代碼，讓我知道

Answer 1

for(ClassSection c : classSectionList) { 
    System.out.println(c.getSchoolClassCode()); 
    // print other attributes 
} 

編輯：

Firt解決方案：

public class ClassSectionDAO implements IClassSectionDAO{ 
    @Override 
    public void selectAllClassSection() { 
    d = new DBManager(); 
    sqliteQuery = new SqliteQueries(); 
    d.executeQuery(sqliteQuery.selectAllFrom("classSection")); 
    try{ 
     while(d.getResultSet().next()){ 
      ClassSection classSection = new ClassSection(); 
      classSection.setClassSectionId(d.getResultSet().getString("classSectionId")); 
      classSection.setSchoolClassCode(d.getResultSet().getString("schoolClassCode")); 
      classSection.setClassSectionNumber(d.getResultSet().getInt("classSectionNumber")); 
      classSection.setClassSectionAvailability(d.getResultSet().getString("classSectionAvailability")); 
      classSectionList.add(classSection); 

      // Solution of ProgrammingIsAwsome 
      System.out.println("classSectionList: " + classSection.getSchoolClassCode()); 
     } 
    } 
    catch(Exception e){ 
     Logger.getLogger(ClassSectionDAO.class.getName()).log(Level.SEVERE, null, e); 
     classSectionList = null; 
    } 
    finally{ 
     d.closeDatabaseConnection(); 
    } 
    } 
} 

解決方法二：

public class ClassSectionDAO implements IClassSectionDAO{ 
    @Override 
    public void selectAllClassSection() { 
    d = new DBManager(); 
    sqliteQuery = new SqliteQueries(); 
    d.executeQuery(sqliteQuery.selectAllFrom("classSection")); 
    try{ 
     while(d.getResultSet().next()){ 
      ClassSection classSection = new ClassSection(); 
      classSection.setClassSectionId(d.getResultSet().getString("classSectionId")); 
      classSection.setSchoolClassCode(d.getResultSet().getString("schoolClassCode")); 
      classSection.setClassSectionNumber(d.getResultSet().getInt("classSectionNumber")); 
      classSection.setClassSectionAvailability(d.getResultSet().getString("classSectionAvailability")); 
      classSectionList.add(classSection); 
     } 
     // Print the list after the while 
     for(ClassSection c : classSectionList) { 
      System.out.println(c.getSchoolClassCode()); 
      // print other attributes 
     } 
    } 
    catch(Exception e){ 
     Logger.getLogger(ClassSectionDAO.class.getName()).log(Level.SEVERE, null, e); 
     classSectionList = null; 
    } 
    finally{ 
     d.closeDatabaseConnection(); 
    } 
    } 
} 

Answer 2

我想你剛剛犯了一個錯字，就像你在問題中已經說過的那樣：我得到一個對象列表（類型爲ClassSection）。這很明顯，因爲你打印了對象列表。

如果你想這樣做的，而環（打印立即每個結果的值），只是改變最後一行的循環中：

System.out.println("classSectionList: " + classSection.getSchoolClassCode()); 

如果你想打印所有的值結果（處理完所有結果後），只需在wile循環後添加Michaël的解決方案即可。