Meisten Bugs gefixt

src/main/java/de/hsel/itech/db/Database.java

@@ -59,7 +59,7 @@ public class Database {
     private Database() {
         Configuration config = Configuration.get();
         dataSource = new MariaDbPoolDataSource("jdbc:mysql://" + config.getDatabase().getHostname()
-                + ":" + config.getDatabase().getPort() + "/" + config.getDatabase().getDatabase());
+                + ":" + config.getDatabase().getPort() + "/" + config.getDatabase().getDatabase() + "?useUnicode=true&characterEncoding=UTF-8");
         try {
             dataSource.setUser(config.getDatabase().getUsername());
             dataSource.setPassword(config.getDatabase().getPassword());
@@ -146,24 +146,33 @@ public class Database {
         return author;
     }
 
+    /**
+     * gets author by name.
+     *
+     * @param name author name
+     * @return {@link de.hsel.itech.db.pojo.Author}
+     */
     @Nullable
     public Author getAuthor(String name) {
+        Map.Entry<ResultSet, Connection> entry = getResultSets(author, "name", name);
+        assert entry != null;
+        assert entry.getKey() != null;
+
         Author author = null;
-
+        ResultSet rs = entry.getKey();
-        Map.Entry<List<ResultSet>, Connection> set = getResultSets(this.author, "name", name);
-
-        if(set == null){
-            return null;
-        }
-
-        if (set.getKey().size() > 0) {
         try {
-                author = new Author(set.getKey().get(0).getLong("id"), set.getKey().get(0).getString("name"));
+            while(rs.next()) {
+                System.out.println(rs.getString("name"));
+            }
+            rs.beforeFirst();
+            if(!rs.next()) {
+                System.out.println("test");
+            }else
+                author = new Author(rs.getLong("id"), rs.getString("name"));
+            entry.getValue().close();
         } catch (SQLException e) {
             e.printStackTrace();
         }
-        }
-
 
         return author;
     }
@@ -178,15 +187,47 @@ public class Database {
     public Category getCategory(long id) {
         Map.Entry<ResultSet, Connection> entry = getResultSet(id, category);
         assert entry != null;
-
         ResultSet rs = entry.getKey();
-        Category category = null;
+
         try {
-            category = new Category(rs.getLong("id"), rs.getString("name"), rs.getString("image"));
+            while(rs.next()) {
-            entry.getValue().close();
+                System.out.println(rs.getLong("id"));
+            }
+
+            rs.beforeFirst();
         } catch (SQLException e) {
             e.printStackTrace();
         }
+        return getCategory(entry);
+    }
+
+    /**
+     * get category by name.
+     *
+     * @param name category name
+     * @return {@link de.hsel.itech.db.pojo.Category}
+     */
+    @Nullable
+    public Category getCategory(String name) {
+        Map.Entry<ResultSet, Connection> entry = getResultSets(category, "name", name);
+        assert entry != null;
+
+        return getCategory(entry);
+    }
+
+    @Nullable
+    private Category getCategory(@NotNull Map.Entry<ResultSet, Connection> entry) {
+        ResultSet rs = entry.getKey();
+        Category category = null;
+        try{
+            System.out.println(rs.getStatement());
+            while(rs.next()) {
+                category = new Category(rs.getLong("id"), rs.getString("name"), rs.getString("image"));
+            }
+            entry.getValue().close();
+        }catch (SQLException ex) {
+            ex.printStackTrace();
+        }
         return category;
     }
 
@@ -212,6 +253,32 @@ public class Database {
         return publisher;
     }
 
+    /**
+     * get publisher by name.
+     *
+     * @param name publisher name
+     * @return {@link de.hsel.itech.db.pojo.Publisher}
+     */
+    @Nullable
+    public Publisher getPublisher(String name) {
+        Map.Entry<ResultSet, Connection> entry = getResultSets(publisher, "name", name);
+        assert entry != null;
+        assert entry.getKey() != null;
+
+        Publisher publisher = null;
+        ResultSet rs = entry.getKey();
+        try {
+            while(rs.next()) {
+                publisher = new Publisher(rs.getLong("id"), rs.getString("name"));
+            }
+            entry.getValue().close();
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+
+        return publisher;
+    }
+
     /**
      * gets list of author ids from database.
      *
@@ -220,11 +287,12 @@ public class Database {
      */
     @Nullable
     private List<Integer> getAuthors(long id) {
-        Map.Entry<List<ResultSet>, Connection> entry = getResultSets(id, authorBook, book);
+        Map.Entry<ResultSet, Connection> entry = getResultSets(id, authorBook, book);
         assert entry != null;
         try {
             List<Integer> list = new ArrayList<>();
-            for (ResultSet rs : entry.getKey()) {
+            ResultSet rs = entry.getKey();
+            while (rs.next()) {
                 list.add(rs.getInt(author));
             }
             entry.getValue().close();
@@ -252,7 +320,10 @@ public class Database {
             Category category = getCategory(rs.getLong(this.category));
             Publisher publisher = getPublisher(rs.getLong(this.publisher));
             List<Integer> authorIds = getAuthors(id);
+            assert category != null;
+            assert publisher != null;
             assert authorIds != null;
+
             List<Author> authors = new ArrayList<>();
             for (int i : authorIds) {
                 Author author = getAuthor(i);
@@ -276,13 +347,14 @@ public class Database {
      */
     @Nullable
     public List<Book> getBooks() {
-        Map.Entry<List<ResultSet>, Connection> entry = getResultSets(book, "id");
+        Map.Entry<ResultSet, Connection> entry = getResultSets(book, "id");
         assert entry != null;
 
         List<Long> ids = new ArrayList<>();
         try {
-            for (ResultSet resultSet : entry.getKey()) {
+            ResultSet rs = entry.getKey();
-                ids.add(resultSet.getLong("id"));
+            while (rs.next()) {
+                ids.add(rs.getLong("id"));
             }
             entry.getValue().close();
         } catch (SQLException ex) {
@@ -349,6 +421,47 @@ public class Database {
 
         int insertCount = 0;
 
+        //author exists ?
+        List<Author> authors = new ArrayList<>();
+        for (Author author : book.getAuthors()) {
+            if (author.getId() == 0) {
+                Author dbAuthor = getAuthor(author.getName());
+                System.out.println(dbAuthor);
+                if (dbAuthor == null) {
+                    insertCount += insert(author);
+                    dbAuthor = getAuthor(author.getName());
+                }
+                authors.add(dbAuthor);
+            }else authors.add(author);
+        }
+
+        //publisher exists ?
+        Publisher publisher;
+        if(book.getPublisher().getId() == 0) {
+            Publisher dbPublisher = getPublisher(book.getPublisher().getName());
+            if(dbPublisher != null)
+                publisher = dbPublisher;
+            else {
+                insertCount += insert(new Publisher(book.getPublisher().getName()));
+                publisher = getPublisher(book.getPublisher().getName());
+            }
+        }else publisher = book.getPublisher();
+
+        //category exists ?
+        Category category;
+        if(book.getCategory().getId() == 0) {
+            Category dbCategory = getCategory(book.getCategory().getName());
+            if(dbCategory != null)
+                category = dbCategory;
+            else {
+                insertCount += insert(new Category(book.getCategory().getName(), book.getCategory().getImage()));
+                category = getCategory(book.getCategory().getName());
+            }
+        }else category = book.getCategory();
+
+        assert publisher != null;
+        assert category != null;
+
         try {
             PreparedStatement statement = connection.prepareStatement("INSERT INTO book(title, description, "
                     + "price, year, publisher, category, image) VALUES (?, ?, ?, ?, ?, ?, ?)");
@@ -356,12 +469,12 @@ public class Database {
             statement.setString(2, book.getDescription());
             statement.setInt(3, book.getPrice());
             statement.setInt(4, book.getYear().getValue());
-            statement.setLong(5, book.getPublisher().getId());
+            statement.setLong(5, publisher.getId());
-            statement.setLong(6, book.getCategory().getId());
+            statement.setLong(6, category.getId());
             statement.setString(7, book.getImage());
             insertCount += statement.executeUpdate();
 
-            for (Author author : book.getAuthors()) {
+            for (Author author : authors) {
                 PreparedStatement authorStatement = connection.prepareStatement("INSERT INTO author_book (author, book) VALUES (?, ?)");
                 statement.setLong(1, author.getId());
                 statement.setLong(2, book.getIsbn());
@@ -519,9 +632,8 @@ public class Database {
 
         int deleteCount = 0;
         try {
-            PreparedStatement statement = connection.prepareStatement("DELETE FROM ? WHERE id=?");
+            PreparedStatement statement = connection.prepareStatement("DELETE FROM " + table + " WHERE id=?");
-            statement.setString(1, table);
+            statement.setLong(1, id);
-            statement.setLong(2, id);
 
             deleteCount = +statement.executeUpdate();
 
@@ -544,9 +656,8 @@ public class Database {
         Connection connection = getConnection();
         try {
             assert connection != null;
-            PreparedStatement statement = connection.prepareStatement("SELECT * FROM ? WHERE ID = ?");
+            PreparedStatement statement = connection.prepareStatement("SELECT * FROM " + table + " WHERE id = ?");
-            statement.setString(1, table);
+            statement.setLong(1, id);
-            statement.setLong(2, id);
             ResultSet resultSet = statement.executeQuery();
             if (resultSet.next()) {
                 return new AbstractMap.SimpleEntry<>(resultSet, connection);
@@ -568,14 +679,12 @@ public class Database {
      * @return {@link java.util.Map.Entry}
      */
     @Nullable
-    private Map.Entry<List<ResultSet>, Connection> getResultSets(long id, @NotNull String table, @NotNull String column) {
+    private Map.Entry<ResultSet, Connection> getResultSets(long id, @NotNull String table, @NotNull String column) {
         Connection connection = getConnection();
         try {
             assert connection != null;
-            PreparedStatement statement = connection.prepareStatement("SELECT * FROM ? WHERE ? = ?");
+            PreparedStatement statement = connection.prepareStatement("SELECT * FROM " + table + " WHERE " + column + " = ?");
-            statement.setString(1, table);
+            statement.setLong(1, id);
-            statement.setString(2, column);
-            statement.setLong(3, id);
 
             return getAllEntries(connection, statement);
         } catch (SQLException ex) {
@@ -592,16 +701,12 @@ public class Database {
      * @return {@link java.util.Map.Entry}
      */
     @Nullable
-    private Map.Entry<List<ResultSet>, Connection> getResultSets(@NotNull String table, @NotNull String column, @NotNull String value) {
+    private Map.Entry<ResultSet, Connection> getResultSets(@NotNull String table, @NotNull String column, @NotNull String value) {
         Connection connection = getConnection();
         try {
             assert connection != null;
-            PreparedStatement statement = connection.prepareStatement("SELECT * FROM ? WHERE ? = ?");
+            PreparedStatement statement = connection.prepareStatement("SELECT * FROM " + table + " WHERE " + column + " = ?");
-            statement.setString(1, table);
+            statement.setString(1, value);
-            statement.setString(2, column);
-            statement.setString(3, value);
-
-            System.out.println(statement);
 
             return getAllEntries(connection, statement);
         } catch (SQLException ex) {
@@ -618,13 +723,11 @@ public class Database {
      * @return {@link java.util.Map.Entry}
      */
     @Nullable
-    private Map.Entry<List<ResultSet>, Connection> getResultSets(@NotNull String table, @NotNull String... columns) {
+    private Map.Entry<ResultSet, Connection> getResultSets(@NotNull String table, @NotNull String... columns) {
         Connection connection = getConnection();
         try {
             assert connection != null;
-            PreparedStatement statement = connection.prepareStatement("SELECT (?) FROM ?");
+            PreparedStatement statement = connection.prepareStatement("SELECT (" + String.join(",", columns) + ") FROM " + table);
-            statement.setString(1, String.join(",", columns));
-            statement.setString(2, table);
 
             return getAllEntries(connection, statement);
         } catch (SQLException ex) {
@@ -641,15 +744,10 @@ public class Database {
      * @return {@link java.util.Map.Entry}
      */
     @Nullable
-    private Map.Entry<List<ResultSet>, Connection> getAllEntries(@NotNull Connection connection, @NotNull PreparedStatement statement) {
+    private Map.Entry<ResultSet, Connection> getAllEntries(@NotNull Connection connection, @NotNull PreparedStatement statement) {
         try {
             ResultSet resultSet = statement.executeQuery();
-
+            return new AbstractMap.SimpleEntry<>(resultSet, connection);
-            Map.Entry<List<ResultSet>, Connection> entry = new AbstractMap.SimpleEntry<>(new ArrayList<>(), connection);
-            while (resultSet.next()) {
-                entry.getKey().add(resultSet);
-            }
-            return entry;
         } catch (SQLException ex) {
             ex.printStackTrace();
         }

src/main/java/de/hsel/itech/db/pojo/Category.java

@@ -1,9 +1,6 @@
 package de.hsel.itech.db.pojo;
 
-import lombok.AllArgsConstructor;
+import lombok.*;
-import lombok.Data;
-import lombok.NonNull;
-import lombok.RequiredArgsConstructor;
 
 /**
  * POJO for Category.
@@ -16,9 +13,15 @@ import lombok.RequiredArgsConstructor;
 @Data
 @AllArgsConstructor
 @RequiredArgsConstructor
+@NoArgsConstructor
 public class Category {
 
     private long id;
     @NonNull private String name;
-    @NonNull private String image;
+    private String image;
+
+    public Category(String name, String image) {
+        this.name = name;
+        this.image = image;
+    }
 }

src/main/java/de/hsel/itech/servlet/BookList.java

@@ -1,5 +1,6 @@
 package de.hsel.itech.servlet;
 
+import de.hsel.itech.db.Database;
 import de.hsel.itech.db.pojo.Author;
 import de.hsel.itech.db.pojo.Book;
 import de.hsel.itech.db.pojo.Category;
@@ -21,7 +22,7 @@ public class BookList extends HttpServlet {
             throws IOException {
 
         //get database object
-        de.hsel.itech.db.Database db = de.hsel.itech.db.Database.getInstance();
+        Database db = Database.getInstance();
 
         //print parameter (debug)
         Enumeration<String> names = req.getParameterNames();
@@ -43,26 +44,23 @@ public class BookList extends HttpServlet {
             String authorName = req.getParameter("author");
             int price = Integer.parseInt(req.getParameter("price"));
             int year = Integer.parseInt(req.getParameter("year"));
-            String category = req.getParameter("category");
+            String categoryName = req.getParameter("category");
             String description = req.getParameter("description");
             String publisher = req.getParameter("publisher");
             String image = req.getParameter("image");
 
 
-            ArrayList<Author> authors = new ArrayList<Author>();
+            ArrayList<Author> authors = new ArrayList<>();
-            Author author = null;
+            String[] authorNames = authorName.split(",");
-
+            for(String name : authorNames) {
-            author = db.getAuthor(authorName);
+                authors.add(new Author(name));
-
-            if(author == null){
-                author = new Author(authorName);
-                db.insert(author);
             }
-            authors.add(author);
+            Category category = new Category();
+            category.setName(categoryName);
             Book book = new Book(
                     authors,
                     new Publisher(publisher),
-                    new Category(category, "DxAzOKSiPoE"),
+                    category,
                     title, Year.of(year),price,description, image
             );
             db.insert(book);