<3>createTableIfNotExist

1. createTableIfNotExit

public class
DbUtils
 
public void
createTableIfNotExist(Class<?> entityType)
throws DbException {
    if
(!tableIsExist(entityType)) {
        SqlInfo sqlInfo = SqlInfoBuilder.buildCreateTableSqlInfo(this,
entityType);
        execNonQuery(sqlInfo);
        String execAfterTableCreated = TableUtils.getExecAfterTableCreated(entityType);
        if (!TextUtils.isEmpty(execAfterTableCreated)) {
            execNonQuery(execAfterTableCreated);
        }
    }
}
 
①　先判断表是否存在
②　获取创建表的sql语句，执行语句
③　类似钩子的操作，解析@Table注释中execAfterTableCreated内容，成为sql
并在表创建成功后执行，如果，sql为空，则跳过此步骤
 
2. 获取创建表的sql语句
public class
SqlInfoBuilder
 
public static
SqlInfo buildCreateTableSqlInfo(DbUtils db,
Class<?> entityType) throws
DbException {
    Table table = Table.get(db,
entityType);
    Id id = table.id;

    StringBuffer sqlBuffer =
new StringBuffer();
    sqlBuffer.append("CREATE TABLE IF NOT EXISTS ");
    sqlBuffer.append(table.tableName);
    sqlBuffer.append(" ( ");

    if (id.isAutoIncrement()) {
        sqlBuffer.append("\"").append(id.getColumnName()).append("\"  ").append("INTEGER
PRIMARY KEY AUTOINCREMENT,");
    }
else {
        sqlBuffer.append("\"").append(id.getColumnName()).append("\"  ").append(id.getColumnDbType()).append("
PRIMARY KEY,");
    }

    Collection<Column> columns = table.columnMap.values();
    for (Column column : columns) {
        if
(column instanceof
Finder) {
            continue;
        }
        sqlBuffer.append("\"").append(column.getColumnName()).append("\"  ");
        sqlBuffer.append(column.getColumnDbType());
        if (ColumnUtils.isUnique(column.getColumnField())) {
            sqlBuffer.append(" UNIQUE");
        }
        if
(ColumnUtils.isNotNull(column.getColumnField())) {
            sqlBuffer.append(" NOT NULL");
        }
        String check = ColumnUtils.getCheck(column.getColumnField());
        if (check !=
null) {
            sqlBuffer.append(" CHECK(").append(check).append(")");
        }
        sqlBuffer.append(",");
    }

    sqlBuffer.deleteCharAt(sqlBuffer.length() -
1);
    sqlBuffer.append(" )");
    return new SqlInfo(sqlBuffer.toString());
}
 
①　table对象的获取，tableIsExist()函数中有提及过程，大体就是获取主键@id以及@column数组信息，放入table对象
②　下面就是一个字符串拼接的活动了(\”java转义字符==双引号字符)：
+ "CREATE TABLE IF NOT EXISTS "
 
+ entity的className
 
+ " ( "
 
+ "\”" + @id(主键名称)  + "\”"  + "INTEGER PRIMARY KEY AUTOINCREMENT,"(默认自增)
 
For。。。循环
+ @clumn(列名称)+(列类型)+" UNIQUE" + " NOT NULL" + " CHECK(" + ")" + ","
结束循环
 
+ 删掉最后一个","
 
+ " )"
③　打包成SqlInfo对象，其实就是把生成的sqlBuffer存入SqlInfo对象的sql变量中
 

1) 默认自增（isAutoIncrement）

public class
Id extends
Column
 
public boolean
isAutoIncrement() {
    if
(!isAutoIncrementChecked) {
        isAutoIncrementChecked
= true;
        isAutoIncrement
= columnField.getAnnotation(NoAutoIncrement.class)
== null
                &&
AUTO_INCREMENT_TYPES.contains(columnFieldClassName);
    }
    return
isAutoIncrement;
}
 
private static final
HashSet<String> INTEGER_TYPES
= new
HashSet<String>(2);
private static final HashSet<String>
AUTO_INCREMENT_TYPES =
new HashSet<String>(4);

static {
    INTEGER_TYPES.add(int.class.getName());
    INTEGER_TYPES.add(Integer.class.getName());

    AUTO_INCREMENT_TYPES.addAll(INTEGER_TYPES);
    AUTO_INCREMENT_TYPES.add(long.class.getName());
    AUTO_INCREMENT_TYPES.add(Long.class.getName());
}
①　isAutoIncrementChecked默认false，所以进入if语句

②　可以看见isAutoIncrementChecked = true

③　接下来就是真正的判断条件：

True = 没有加入注释NoAutoIncrement
并且 是int或者long类型 会自增

False = 除此之外

 

1) 列类型

回到初始化Column哪里

 Column(Class<?> entityType,
Field field) {
    this.columnField
= field;
    this.columnConverter = ColumnConverterFactory.getColumnConverter(field.getType());
    this.columnName
= ColumnUtils.getColumnNameByField(field);
    if (this.columnConverter
!= null) {
        this.defaultValue
= this.columnConverter.getFieldValue(ColumnUtils.getColumnDefaultValue(field));
    }
else {
        this.defaultValue
= null;
    }
    this.getMethod
= ColumnUtils.getColumnGetMethod(entityType,
field);
    this.setMethod
= ColumnUtils.getColumnSetMethod(entityType,
field);
}
 

public static
ColumnConverter getColumnConverter(Class columnType) {
    if
(columnType_columnConverter_map.containsKey(columnType.getName())) {
        return
columnType_columnConverter_map.get(columnType.getName());
    }
else if (ColumnConverter.class.isAssignableFrom(columnType)) {
        try
{
            ColumnConverter columnConverter = (ColumnConverter) columnType.newInstance();
            if (columnConverter !=
null) {
                columnType_columnConverter_map.put(columnType.getName(),
columnConverter);
            }
            return
columnConverter;
        }
catch (Throwable e) {
        }
    }
    return null;
}
 
private static final
ConcurrentHashMap<String,
ColumnConverter> columnType_columnConverter_map;

static {
    columnType_columnConverter_map
= new
ConcurrentHashMap<String,
ColumnConverter>();

    BooleanColumnConverter booleanColumnConverter =
new BooleanColumnConverter();
    columnType_columnConverter_map.put(boolean.class.getName(),
booleanColumnConverter);
    columnType_columnConverter_map.put(Boolean.class.getName(),
booleanColumnConverter);

    ByteArrayColumnConverter byteArrayColumnConverter =
new ByteArrayColumnConverter();
    columnType_columnConverter_map.put(byte[].class.getName(),
byteArrayColumnConverter);

    ByteColumnConverter byteColumnConverter =
new ByteColumnConverter();
    columnType_columnConverter_map.put(byte.class.getName(),
byteColumnConverter);
    columnType_columnConverter_map.put(Byte.class.getName(),
byteColumnConverter);

    CharColumnConverter charColumnConverter =
new CharColumnConverter();
    columnType_columnConverter_map.put(char.class.getName(),
charColumnConverter);
    columnType_columnConverter_map.put(Character.class.getName(),
charColumnConverter);

    DateColumnConverter dateColumnConverter =
new DateColumnConverter();
    columnType_columnConverter_map.put(Date.class.getName(),
dateColumnConverter);

    DoubleColumnConverter doubleColumnConverter =
new DoubleColumnConverter();
    columnType_columnConverter_map.put(double.class.getName(),
doubleColumnConverter);
    columnType_columnConverter_map.put(Double.class.getName(),
doubleColumnConverter);

    FloatColumnConverter floatColumnConverter =
new FloatColumnConverter();
    columnType_columnConverter_map.put(float.class.getName(),
floatColumnConverter);
    columnType_columnConverter_map.put(Float.class.getName(),
floatColumnConverter);

    IntegerColumnConverter integerColumnConverter =
new IntegerColumnConverter();
    columnType_columnConverter_map.put(int.class.getName(),
integerColumnConverter);
    columnType_columnConverter_map.put(Integer.class.getName(),
integerColumnConverter);

    LongColumnConverter longColumnConverter =
new LongColumnConverter();
    columnType_columnConverter_map.put(long.class.getName(),
longColumnConverter);
    columnType_columnConverter_map.put(Long.class.getName(),
longColumnConverter);

    ShortColumnConverter shortColumnConverter =
new ShortColumnConverter();
    columnType_columnConverter_map.put(short.class.getName(),
shortColumnConverter);
    columnType_columnConverter_map.put(Short.class.getName(),
shortColumnConverter);

    SqlDateColumnConverter sqlDateColumnConverter =
new SqlDateColumnConverter();
    columnType_columnConverter_map.put(java.sql.Date.class.getName(),
sqlDateColumnConverter);

    StringColumnConverter stringColumnConverter =
new StringColumnConverter();
    columnType_columnConverter_map.put(String.class.getName(),
stringColumnConverter);
}
 
 

①　可以看到最终是从columnType_columnConverter_map缓存中，获取一个IntegerColumnConverter对象（这里以int类型举例）

 

sqlBuffer.append(column.getColumnDbType());
 

public
ColumnDbType getColumnDbType() {
    return
columnConverter.getColumnDbType();
}
 

public
ColumnDbType getColumnDbType() {
    return
ColumnDbType.INTEGER;
}
 

public enum
ColumnDbType {

    INTEGER("INTEGER"),
REAL("REAL"),
TEXT("TEXT"),
BLOB("BLOB");

    private String
value;

    ColumnDbType(String value) {
        this.value
= value;
    }

    @Override
    public
String toString() {
        return
value;
    }
}
②　看到最终拿到的是一个枚举，值为"INTEGER"

 
3. Database执行sql语句创建表
public void
createTableIfNotExist(Class<?> entityType)
throws DbException {
    if
(!tableIsExist(entityType)) {
        SqlInfo sqlInfo = SqlInfoBuilder.buildCreateTableSqlInfo(this,
entityType);
        execNonQuery(sqlInfo);
        String execAfterTableCreated = TableUtils.getExecAfterTableCreated(entityType);
        if (!TextUtils.isEmpty(execAfterTableCreated)) {
            execNonQuery(execAfterTableCreated);
        }
    }
}
public void
execNonQuery(SqlInfo sqlInfo)
throws DbException {
    debugSql(sqlInfo.getSql());
    try {
        if
(sqlInfo.getBindArgs() != null) {
            database.execSQL(sqlInfo.getSql(),
sqlInfo.getBindArgsAsArray());
        }
else {
            database.execSQL(sqlInfo.getSql());
        }
    } catch
(Throwable e) {
        throw new
DbException(e);
    }
}
 
Ok，一个简单的语句执行，创建完毕