String dictInfoCode = dictInfo.getCodeFieldName(); List<ColumnInfo> columnsByTableName = this.getColumnsByTableName(tableName); String sqlString = "SELECT "; List<String> list = new ArrayList<>(); for (ColumnInfo columnInfo : columnsByTableName) { list.add("`" + columnInfo.getColumnName() + "`"); } sqlString += StringUtils.join(list, ','); StringUtils.join(list, ','); sqlString += " FROM " + tableName; sqlString += " WHERE " + "`" + dictInfoCode + "`" + " = " + " '" + code + "' "; //System.out.println(" SQL = " + sqlString); // 查 Map<String, Object> map = this.superManagerSelectOne(sqlString);

您好，以下是实现安卓开发 compose 现在有一个List<Note> 要实现拖动排序功能jetpack room数据库的 kotlin 代码示例： 首先，您需要在 build.gradle 文件中添加以下依赖： ``` implementation "androidx.compose.foundation:foundation-layout:1.0.0-beta02" implementation "androidx.compose.material:material:1.0.0-beta02" implementation "androidx.compose.runtime:runtime-livedata:1.0.0-beta02" implementation "androidx.compose.ui:ui:1.0.0-beta02" implementation "androidx.compose.ui:ui-tooling:1.0.0-beta02" implementation "androidx.room:room-runtime:2.3.0" kapt "androidx.room:room-compiler:2.3.0" ``` 然后，您可以使用 Jetpack Compose 实现一个可拖动的列表，并使用 Room 数据库存储和加载数据。以下是完整的 Kotlin 代码： ``` import androidx.compose.foundation.background import androidx.compose.foundation.gestures.draggable import androidx.compose.foundation.layout.Box import androidx.compose.foundation.layout.Column import androidx.compose.foundation.layout.fillMaxSize import androidx.compose.foundation.layout.padding import androidx.compose.material.Button import androidx.compose.material.Text import androidx.compose.runtime.* import androidx.compose.ui.Modifier import androidx.compose.ui.draw.alpha import androidx.compose.ui.graphics.Color import androidx.compose.ui.unit.dp import androidx.lifecycle.LiveData import androidx.lifecycle.MutableLiveData import androidx.room.ColumnInfo import androidx.room.Entity import androidx.room.PrimaryKey import androidx.room.Room import androidx.room.RoomDatabase import androidx.room.migration.Migration import androidx.sqlite.db.SupportSQLiteDatabase import kotlinx.coroutines.Dispatchers import kotlinx.coroutines.launch @Entity(tableName = "notes") data class Note( @PrimaryKey val id: Int, @ColumnInfo(name = "text") val text: String, @ColumnInfo(name = "position") var position: Int ) @Dao interface NoteDao { @Query("SELECT * FROM notes ORDER BY position ASC") fun getNotes(): LiveData<List<Note>> @Insert(onConflict = OnConflictStrategy.REPLACE) suspend fun insert(note: Note) @Update suspend fun update(note: Note) } @Database(entities = arrayOf(Note::class), version = 2) abstract class AppDatabase : RoomDatabase() { abstract fun noteDao(): NoteDao companion object { private var instance: AppDatabase? = null fun getInstance(context: Context): AppDatabase { return instance ?: synchronized(this) { instance ?: buildDatabase(context).also { instance = it } } } private fun buildDatabase(context: Context): AppDatabase { return Room.databaseBuilder(context, AppDatabase::class.java, "notes.db") .addMigrations(object : Migration(1, 2) { override fun migrate(database: SupportSQLiteDatabase) { database.execSQL("ALTER TABLE notes ADD COLUMN position INTEGER DEFAULT 0") } }) .build() } } } class NoteViewModel : ViewModel() { private val appDatabase = AppDatabase.getInstance(MyApplication.context) private val noteDao = appDatabase.noteDao() private val _notes = MutableLiveData<List<Note>>() init { loadNotes() } fun getNotes(): LiveData<List<Note>> { return _notes } fun addNote() { viewModelScope.launch(Dispatchers.IO) { val count = noteDao.getNotes().value?.size ?: 0 noteDao.insert(Note(count + 1, "Note ${count + 1}", count + 1)) } } fun updateNotePosition(note: Note, position: Int) { viewModelScope.launch(Dispatchers.IO) { note.position = position noteDao.update(note) } } private fun loadNotes() { viewModelScope.launch(Dispatchers.IO) { val notes = noteDao.getNotes().value ?: emptyList() _notes.postValue(notes) } } } @Composable fun NotesList(noteViewModel: NoteViewModel) { val notes by noteViewModel.getNotes().observeAsState(listOf()) Column(modifier = Modifier.padding(16.dp)) { Button(onClick = { noteViewModel.addNote() }) { Text("Add Note") } for (i in notes.indices) { val note = notes[i] Box( modifier = Modifier .fillMaxSize() .alpha(if (note.position == i) 1f else 0.5f) .background(Color.White) .draggable( orientation = Orientation.Vertical, onDragStarted = { /* Do nothing */ }, onDragStopped = { noteViewModel.updateNotePosition(note, it) } ) ) { Text( text = note.text, modifier = Modifier.padding(16.dp) ) } } } } class MainActivity : ComponentActivity() { private val noteViewModel by viewModels<NoteViewModel>() override fun onCreate(savedInstanceState: Bundle?) { super.onCreate(savedInstanceState) setContent { NotesList(noteViewModel) } } } ``` 代码说明： 1.定义 Note 实体类，其中包含 id、text 和 position 字段。 2.定义 NoteDao 接口，其中包含 getNotes()、insert() 和 update() 函数。 3.AppDatabase 是一个 Room 数据库，它包含 NoteDao。 4.NoteViewModel 是一个 ViewModel，它包含一个 LiveData 列表，用于存储 Note 对象列表。 5.NotesList 是一个 Composable 函数，它显示 Note 对象列表，并允许用户重新排序它们。 6.在主 Activity 中使用 NotesList Composable 函数。 该代码依赖于 Jetpack Compose 和 Room 数据库。Jetpack Compose 提供了一种简单的方法来实现可拖动的列表，而 Room 数据库用于保存和加载 Note 数据。

以下是一个使用Druid解析SQL并分析字段血缘关系的Java代码示例： ``` import com.alibaba.druid.sql.SQLUtils; import com.alibaba.druid.sql.ast.SQLExpr; import com.alibaba.druid.sql.ast.SQLStatement; import com.alibaba.druid.sql.ast.expr.*; import com.alibaba.druid.sql.ast.statement.*; import com.alibaba.druid.sql.dialect.mysql.parser.MySqlStatementParser; import com.alibaba.druid.sql.parser.SQLStatementParser; import java.util.*; public class DruidSqlParser { public static void main(String[] args) { String sql = "SELECT t1.id, t2.name FROM table1 t1 JOIN table2 t2 ON t1.id = t2.id WHERE t1.age > 18"; List<ColumnInfo> columnInfoList = analyzeSql(sql); for (ColumnInfo columnInfo : columnInfoList) { System.out.println(columnInfo); } } public static List<ColumnInfo> analyzeSql(String sql) { List<ColumnInfo> columnInfoList = new ArrayList<>(); SQLStatementParser parser = new MySqlStatementParser(sql); List<SQLStatement> statementList = parser.parseStatementList(); for (SQLStatement statement : statementList) { if (statement instanceof SQLSelectStatement) { SQLSelectStatement selectStatement = (SQLSelectStatement) statement; SQLSelectQueryBlock queryBlock = selectStatement.getSelect().getQueryBlock(); analyzeSelectItems(queryBlock.getSelectList(), columnInfoList); analyzeWhere(queryBlock.getWhere(), columnInfoList); analyzeJoin(queryBlock.getFrom(), columnInfoList); } } return columnInfoList; } private static void analyzeSelectItems(List<SQLSelectItem> selectItems, List<ColumnInfo> columnInfoList) { for (SQLSelectItem selectItem : selectItems) { SQLExpr expr = selectItem.getExpr(); String columnName = null; String tableName = null; if (expr instanceof SQLPropertyExpr) { SQLPropertyExpr propertyExpr = (SQLPropertyExpr) expr; columnName = propertyExpr.getName(); tableName = propertyExpr.getOwner().getName(); } else if (expr instanceof SQLIdentifierExpr) { SQLIdentifierExpr identifierExpr = (SQLIdentifierExpr) expr; columnName = identifierExpr.getName(); } if (columnName != null) { ColumnInfo columnInfo = new ColumnInfo(columnName, tableName, true); if (!columnInfoList.contains(columnInfo)) { columnInfoList.add(columnInfo); } } } } private static void analyzeWhere(SQLExpr whereExpr, List<ColumnInfo> columnInfoList) { if (whereExpr instanceof SQLBinaryOpExpr) { SQLBinaryOpExpr binaryOpExpr = (SQLBinaryOpExpr) whereExpr; analyzeWhere(binaryOpExpr.getLeft(), columnInfoList); analyzeWhere(binaryOpExpr.getRight(), columnInfoList); } else if (whereExpr instanceof SQLBinaryOpExprGroup) { SQLBinaryOpExprGroup binaryOpExprGroup = (SQLBinaryOpExprGroup) whereExpr; for (SQLExpr sqlExpr : binaryOpExprGroup.getItems()) { analyzeWhere(sqlExpr, columnInfoList); } } else if (whereExpr instanceof SQLIdentifierExpr) { SQLIdentifierExpr identifierExpr = (SQLIdentifierExpr) whereExpr; String columnName = identifierExpr.getName(); ColumnInfo columnInfo = new ColumnInfo(columnName, null, false); if (!columnInfoList.contains(columnInfo)) { columnInfoList.add(columnInfo); } } } private static void analyzeJoin(SQLTableSource tableSource, List<ColumnInfo> columnInfoList) { if (tableSource instanceof SQLJoinTableSource) { SQLJoinTableSource joinTableSource = (SQLJoinTableSource) tableSource; analyzeJoin(joinTableSource.getLeft(), columnInfoList); analyzeJoin(joinTableSource.getRight(), columnInfoList); SQLExpr onExpr = joinTableSource.getCondition(); if (onExpr instanceof SQLBinaryOpExpr) { SQLBinaryOpExpr binaryOpExpr = (SQLBinaryOpExpr) onExpr; SQLExpr leftExpr = binaryOpExpr.getLeft(); SQLExpr rightExpr = binaryOpExpr.getRight(); if (leftExpr instanceof SQLPropertyExpr && rightExpr instanceof SQLPropertyExpr) { SQLPropertyExpr leftPropertyExpr = (SQLPropertyExpr) leftExpr; SQLPropertyExpr rightPropertyExpr = (SQLPropertyExpr) rightExpr; String leftColumnName = leftPropertyExpr.getName(); String leftTableName = leftPropertyExpr.getOwner().getName(); String rightColumnName = rightPropertyExpr.getName(); String rightTableName = rightPropertyExpr.getOwner().getName(); ColumnInfo leftColumnInfo = new ColumnInfo(leftColumnName, leftTableName, false); ColumnInfo rightColumnInfo = new ColumnInfo(rightColumnName, rightTableName, false); if (columnInfoList.contains(leftColumnInfo)) { int index = columnInfoList.indexOf(leftColumnInfo); columnInfoList.get(index).setTableName(leftTableName); } if (columnInfoList.contains(rightColumnInfo)) { int index = columnInfoList.indexOf(rightColumnInfo); columnInfoList.get(index).setTableName(rightTableName); } } } } else if (tableSource instanceof SQLSubqueryTableSource) { SQLSubqueryTableSource subqueryTableSource = (SQLSubqueryTableSource) tableSource; SQLSelect subSelect = subqueryTableSource.getSelect(); analyzeSelectItems(subSelect.getQueryBlock().getSelectList(), columnInfoList); analyzeWhere(subSelect.getQueryBlock().getWhere(), columnInfoList); analyzeJoin(subSelect.getQueryBlock().getFrom(), columnInfoList); } else if (tableSource instanceof SQLExprTableSource) { SQLExprTableSource exprTableSource = (SQLExprTableSource) tableSource; String tableName = null; if (exprTableSource.getAlias() != null) { tableName = exprTableSource.getAlias(); } else if (exprTableSource.getExpr() instanceof SQLIdentifierExpr) { tableName = ((SQLIdentifierExpr) exprTableSource.getExpr()).getName(); } for (ColumnInfo columnInfo : columnInfoList) { if (columnInfo.getTableName() == null) { columnInfo.setTableName(tableName); } } } } } class ColumnInfo { private String columnName; private String tableName; private boolean isSelectItem; public ColumnInfo(String columnName, String tableName, boolean isSelectItem) { this.columnName = columnName; this.tableName = tableName; this.isSelectItem = isSelectItem; } public String getColumnName() { return columnName; } public void setColumnName(String columnName) { this.columnName = columnName; } public String getTableName() { return tableName; } public void setTableName(String tableName) { this.tableName = tableName; } public boolean isSelectItem() { return isSelectItem; } public void setSelectItem(boolean selectItem) { isSelectItem = selectItem; } @Override public String toString() { return "ColumnInfo{" + "columnName='" + columnName + '\'' + ", tableName='" + tableName + '\'' + ", isSelectItem=" + isSelectItem + '}'; } @Override public boolean equals(Object o) { if (this == o) return true; if (o == null || getClass() != o.getClass()) return false; ColumnInfo that = (ColumnInfo) o; return Objects.equals(columnName, that.columnName) && Objects.equals(tableName, that.tableName); } @Override public int hashCode() { return Objects.hash(columnName, tableName); } } ``` 这个代码实现了对SELECT、WHERE和JOIN三个部分的分析，并且能够正确地识别出每个字段所属的表和是否是SELECT中的选择项。你可以根据自己的需求对这个代码进行扩展和修改。