LitePal 数据库基本操作和关联表方式（一对多）（原创）

说明：个人直接项目测试类写博客，有个别地方删除，就不特别自个创建项目简化说明使用，可以仅仅看大概主要实现功能即可。

1、初始化（工程目录assets下创建litepal.xml文件）

litepal.xml文件内容：

<?xml version="1.0" encoding="utf-8"?>
<litepal><!--Define the database name of your application.By default each database name should be end with .db.If you didn't name your database end with .db,LitePal would plus the suffix automaticly for you.For example:<dbname value="demo" ></dbname>数据库文件名--><dbname value="test" /><!--Define the version of your database. Each time you wantto upgrade your database, the version tag would helps.Modify the models you defined in the mapping tag, and justmake the version value plus one, the upgrade of databasewill be processed automaticly without concern.For example:<version value="1" ></version>数据库版本号：注意，修改table表参数或者增加table表都需要在此修改叠加版本号--><version value="1" /><!--Define your models in the list with mapping tag, LitePal willcreate tables for each mapping class. The supported fieldsdefined in models will be mapped into columns.For example:<list><mapping class="com.test.model.Reader"></mapping><mapping class="com.test.model.Magazine"></mapping></list>数据库table表--><list><mapping class="com.example.myapplication.dao.WeiTingTable" /><mapping class="com.example.myapplication.dao.WeiTingRoadInfo" /></list><!--Define where the .db file should be. "internal" means the .db filewill be stored in the database folder of internal storage which noone can access. "external" means the .db file will be stored in thepath to the directory on the primary external storage device wherethe application can place persistent files it owns which everyonecan access. "internal" will act as default.For example:<storage value="external"></storage>数据库存放目录：工程目录下/database下--><storage value="external" />
</litepal>

2、Activity onCreate()初始化LitePal

@Overrideprotected void onCreate(@Nullable Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_dao);LitePal.initialize(this);}

3、关联表bean

package com.example.myapplication.dao;import android.util.Log;import com.orhanobut.logger.Logger;import org.litepal.LitePal;
import org.litepal.crud.LitePalSupport;import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;/*** 表结构：一对多关系*/
public class WeiTingRoadInfo extends LitePalSupport {private String adCode;private String wholeRoadCode;private String wholeRoadName;private String partRoadCode;private String partRoadName;/*** 提供子表获取其id** @return*/public long getId() {return getBaseObjId();}/*** 从数据库获取子表，仅供查询不可用于操作添加更新保存子表功能（操作使用getWeiTingTableList()）** @return*/public List<WeiTingTable> getWeiTingTablesFromDb() {String linkId = this.getClass().getSimpleName().toLowerCase();// 对应子表id为：weitingtable_idreturn LitePal.where(linkId + "_id=?", String.valueOf(getBaseObjId())).find(WeiTingTable.class);}/*** 用于新增和更新子表** @return*/public List<WeiTingTable> getWeiTingTableList() {return weiTingTableList;}private List<WeiTingTable> weiTingTableList = new ArrayList<>();public String getAdCode() {return adCode == null ? "" : adCode;}public void setAdCode(String adCode) {this.adCode = adCode;}public String getWholeRoadCode() {return wholeRoadCode == null ? "" : wholeRoadCode;}public void setWholeRoadCode(String wholeRoadCode) {this.wholeRoadCode = wholeRoadCode;}public String getWholeRoadName() {return wholeRoadName == null ? "" : wholeRoadName;}public void setWholeRoadName(String wholeRoadName) {this.wholeRoadName = wholeRoadName;}public String getPartRoadCode() {return partRoadCode == null ? "" : partRoadCode;}public void setPartRoadCode(String partRoadCode) {this.partRoadCode = partRoadCode;}public String getPartRoadName() {return partRoadName == null ? "" : partRoadName;}public void setPartRoadName(String partRoadName) {this.partRoadName = partRoadName;}@Overridepublic boolean equals(Object o) {if (this == o) return true;if (o == null || getClass() != o.getClass()) return false;WeiTingRoadInfo that = (WeiTingRoadInfo) o;return adCode.equals(that.adCode) &&wholeRoadCode.equals(that.wholeRoadCode) &&wholeRoadName.equals(that.wholeRoadName) &&partRoadCode.equals(that.partRoadCode) &&partRoadName.equals(that.partRoadName);}@Overridepublic int hashCode() {return Objects.hash(adCode, wholeRoadCode, wholeRoadName, partRoadCode, partRoadName);}@Overridepublic String toString() {return "WeiTingRoadInfo{" +"adCode='" + adCode + '\'' +", wholeRoadCode='" + wholeRoadCode + '\'' +", wholeRoadName='" + wholeRoadName + '\'' +", partRoadCode='" + partRoadCode + '\'' +", partRoadName='" + partRoadName + '\'' +'}';}@Overridepublic int delete() {// 将子表同步删除List<WeiTingTable> weiTingTables = getWeiTingTablesFromDb();for (WeiTingTable weiTingTable : weiTingTables) {weiTingTable.delete();}return super.delete();}public synchronized boolean saveToFirst() {if (LitePal.findLast(this.getClass()).equals(this)) {Log.e("DaoActivityLog", "已是最新位置的数据，不做刷新缓存处理。");Logger.e("已是最新位置的数据，不做刷新缓存处理。");return true;}Log.e("DaoActivityLog", "不是最新位置的数据，需要刷新缓存处理。");List<WeiTingTable> weiTingTables = getWeiTingTablesFromDb();List<WeiTingTable> newWeiTingTables = copyList(weiTingTables);if (newWeiTingTables != null) {// 避免一些拷贝异常情况清理旧的缓存数据// 拷贝全部数据正常saveStuTables(newWeiTingTables);} else {Logger.e("拷贝旧数据失败，不做刷新缓存处理。");return false;}return save();// 重新缓存}private void saveStuTables(List<WeiTingTable> weiTingTables) {delete();// 删除了子表for (WeiTingTable weiTingTable : weiTingTables) {weiTingTable.setWeiTingRoadInfo(this);weiTingTable.save();// 重新缓存子表getWeiTingTableList().add(weiTingTable);// 重新添加子表}}private List<WeiTingTable> copyList(List<WeiTingTable> weiTingTables) {List<WeiTingTable> newWeiTingTables = new ArrayList<>();for (WeiTingTable weiTingTable : weiTingTables) {WeiTingTable clone = (WeiTingTable) copy(weiTingTable);if (clone == null) return null;clone.setWeiTingRoadInfo(this);newWeiTingTables.add(clone);}return newWeiTingTables;}/*** 深拷贝** @param old* @return*/private Object copy(Object old) {Object clazz;try {ByteArrayOutputStream baos = new ByteArrayOutputStream();ObjectOutputStream oos = new ObjectOutputStream(baos);oos.writeObject(old);ByteArrayInputStream bais = new ByteArrayInputStream(baos.toByteArray());ObjectInputStream ois = new ObjectInputStream(bais);clazz = ois.readObject();} catch (Exception e) {Logger.e(e, "copy fail");return null;}return clazz;}}

子表类：

package com.example.myapplication.dao;import org.litepal.LitePal;
import org.litepal.annotation.Column;
import org.litepal.crud.LitePalSupport;import java.io.Serializable;/*** 表结构：多对一*/
public class WeiTingTable extends LitePalSupport implements Serializable {/*** 缓存对应的母表id，便于查询关联表*/private long road_id;private String hphm;private String hpzl;private WeiTingRoadInfo weiTingRoadInfo;public String getHphm() {return hphm == null ? "" : hphm;}public void setHphm(String hphm) {this.hphm = hphm;}public String getHpzl() {return hpzl == null ? "" : hpzl;}public void setHpzl(String hpzl) {this.hpzl = hpzl;}public String getWei_ting_id() {return wei_ting_id == null ? "" : wei_ting_id;}public void setWei_ting_id(String wei_ting_id) {this.wei_ting_id = wei_ting_id;}public void setWeiTingRoadInfo(WeiTingRoadInfo weiTingRoadInfo) {if (weiTingRoadInfo != null) {weiTingRoadInfo.getWeiTingTableList().add(this);weiTingRoadInfo.save();road_id = weiTingRoadInfo.getId();// 前提是WeiTingRoadInfo 先save才有对应id，否则0this.weiTingRoadInfo = weiTingRoadInfo;}}/*** 关联表获取需要查询对应子表的id获取** @return*/public WeiTingRoadInfo getWeiTingRoadInfo() {if (weiTingRoadInfo != null) return weiTingRoadInfo;// 通过缓存id获取对应关联表return LitePal.find(WeiTingRoadInfo.class, road_id);}}

4、DaoActivity具体实现

package com.example.myapplication;import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.text.TextUtils;
import android.util.Log;
import android.view.View;import com.example.myapplication.dao.WeiTingRoadInfo;
import com.example.myapplication.dao.WeiTingTable;import org.litepal.LitePal;import java.util.List;public class DaoActivity extends AppCompatActivity {private static final String TAG = DaoActivity.class.getSimpleName() + "Log";@Overrideprotected void onCreate(@Nullable Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_dao);LitePal.initialize(this);}private int mCount;public void save(View view) {if (mCount < 10) {Log.e(TAG, "第一次缓存");++mCount;WeiTingRoadInfo weiTingRoadInfo = new WeiTingRoadInfo();weiTingRoadInfo.setAdCode("weiTingRoadInfoAdCode" + mCount);weiTingRoadInfo.setPartRoadName("weiTingPartRoadName" + mCount);weiTingRoadInfo.setPartRoadCode("weiTingRoadInfoPartRoadCode" + mCount);weiTingRoadInfo.setWholeRoadCode("weiTingRoadInfoWholeRoadCode" + mCount);weiTingRoadInfo.setWholeRoadName("weiTingRoadInfoWholeRoadName" + mCount);boolean save = weiTingRoadInfo.save();Log.e(TAG, "weiTingRoadInfo1-1: " + save + " - " + weiTingRoadInfo.getAdCode());for (int i = mCount - 1; i < mCount + 10; ++i) {WeiTingTable weiTingTable = new WeiTingTable();weiTingTable.setHphm("weiTingTableHphm" + i);weiTingTable.setHpzl("weiTingTableHpzl" + i);weiTingTable.setWeiTingRoadInfo(weiTingRoadInfo);weiTingTable.save();
//                weiTingRoadInfo.getWeiTingTableList().add(weiTingTable);}
//            boolean save = weiTingRoadInfo.save();
//            Log.e(TAG, "weiTingRoadInfo1-2: " + save + " - " + weiTingRoadInfo.getAdCode());mCount += 10;} else if (mCount < 20) {Log.e(TAG, "第二次缓存");++mCount;WeiTingRoadInfo weiTingRoadInfo = new WeiTingRoadInfo();weiTingRoadInfo.setAdCode("weiTingRoadInfoAdCode" + mCount);weiTingRoadInfo.setPartRoadName("weiTingPartRoadName" + mCount);weiTingRoadInfo.setPartRoadCode("weiTingRoadInfoPartRoadCode" + mCount);weiTingRoadInfo.setWholeRoadCode("weiTingRoadInfoWholeRoadCode" + mCount);weiTingRoadInfo.setWholeRoadName("weiTingRoadInfoWholeRoadName" + mCount);boolean save = weiTingRoadInfo.save();
//            Log.e(TAG, "weiTingRoadInfo2-1: " + save + " - " + weiTingRoadInfo.getAdCode());for (int i = mCount - 1; i < mCount + 10; ++i) {WeiTingTable weiTingTable = new WeiTingTable();weiTingTable.setHphm("value" + i);weiTingTable.setHpzl("value" + i);weiTingTable.setWeiTingRoadInfo(weiTingRoadInfo);weiTingTable.save();
//                weiTingRoadInfo.getWeiTingTableList().add(weiTingTable);}
//            boolean save = weiTingRoadInfo.save();
//            Log.e(TAG, "weiTingRoadInfo2-2: " + save + " - " + weiTingRoadInfo.getAdCode());mCount += 10;} else {Log.e(TAG, "之后缓存");++mCount;WeiTingRoadInfo weiTingRoadInfo = new WeiTingRoadInfo();weiTingRoadInfo.setAdCode("weiTingRoadInfoAdCode" + mCount);weiTingRoadInfo.setPartRoadName("weiTingPartRoadName" + mCount);weiTingRoadInfo.setPartRoadCode("weiTingRoadInfoPartRoadCode" + mCount);weiTingRoadInfo.setWholeRoadCode("weiTingRoadInfoWholeRoadCode" + mCount);weiTingRoadInfo.setWholeRoadName("weiTingRoadInfoWholeRoadName" + mCount);boolean save = weiTingRoadInfo.save();Log.e(TAG, "weiTingRoadInfo3-1: " + save + " - " + weiTingRoadInfo.getAdCode());int count = 0;for (int i = mCount - 1; i < mCount + 10; ++i) {WeiTingTable weiTingTable = new WeiTingTable();weiTingTable.setHphm("value" + i);weiTingTable.setHpzl("value" + i);if (i % 2 == 0) {weiTingTable.setMidPicPath("valueMidPicPath" + i);}weiTingTable.setWeiTingRoadInfo(weiTingRoadInfo);weiTingTable.save();
//                weiTingRoadInfo.getWeiTingTableList().add(weiTingTable);count = i;}
//            save = weiTingRoadInfo.save();
//            Log.e(TAG, "weiTingRoadInfo3-2: " + save + " - " + weiTingRoadInfo.getAdCode());mCount += count;}Log.e(TAG, "mCount: " + mCount);}public void get(View view) {List<WeiTingRoadInfo> weiTingRoadInfos = LitePal.findAll(WeiTingRoadInfo.class);for (WeiTingRoadInfo weiTingRoadInfo : weiTingRoadInfos) {List<WeiTingTable> weiTingTables = weiTingRoadInfo.getWeiTingTablesFromDb();for (WeiTingTable weiTingTable : weiTingTables) {Log.e(TAG, "weiTingTable: " + weiTingTable.getHphm());Log.e(TAG, "weiTingRoadInfo: " + weiTingRoadInfo.getAdCode());}}}public void update(View view) {WeiTingRoadInfo first;if (System.currentTimeMillis() % 2 == 0) {first = LitePal.findLast(WeiTingRoadInfo.class);} else {first = LitePal.findFirst(WeiTingRoadInfo.class);}Log.e(TAG, "first: " + first.getAdCode());first.saveToFirst();WeiTingRoadInfo last = LitePal.findLast(WeiTingRoadInfo.class);Log.e(TAG, "last: " + last.getAdCode());for (WeiTingTable weiTingTable : last.getWeiTingTablesFromDb()) {Log.e(TAG, "last weiTingTable: " + weiTingTable.getHphm());}}public void delete(View view) {WeiTingRoadInfo weiTingRoadInfo = LitePal.findFirst(WeiTingRoadInfo.class);weiTingRoadInfo.delete();}public void deleteAll(View view) {LitePal.deleteAll(WeiTingRoadInfo.class);}public void add(View view) {WeiTingRoadInfo weiTingRoadInfo = LitePal.findFirst(WeiTingRoadInfo.class);WeiTingTable weiTingTable = new WeiTingTable();weiTingTable.setHphm("000000");weiTingTable.setWeiTingRoadInfo(weiTingRoadInfo);weiTingTable.save();}public void updateStu(View view) {WeiTingRoadInfo weiTingRoadInfo = LitePal.findFirst(WeiTingRoadInfo.class);List<WeiTingTable> weiTingTableList = weiTingRoadInfo.getWeiTingTablesFromDb();WeiTingTable weiTingTable = weiTingTableList.get(0);weiTingTable.setHphm("update00000");weiTingTable.setWeiTingRoadInfo(weiTingRoadInfo);weiTingTable.save();}public void deleteStu(View view) {
//        WeiTingRoadInfo weiTingRoadInfo = LitePal.findFirst(WeiTingRoadInfo.class);
//        List<WeiTingTable> weiTingTableList = weiTingRoadInfo.getWeiTingTablesFromDb();
//        WeiTingTable weiTingTable = weiTingTableList.get(0);
//        weiTingTable.delete();deleteWeiTingInvalidData();}public void getStu(View view) {List<WeiTingTable> all = LitePal.findAll(WeiTingTable.class);for (WeiTingTable weiTingTable : all) {Log.e(TAG, "weiTingTable: " + weiTingTable.getHphm());}}public void getParent(View view) {WeiTingTable first = LitePal.findFirst(WeiTingTable.class);WeiTingRoadInfo weiTingRoadInfo = first.getWeiTingRoadInfo();Log.e(TAG, "weiTingRoadInfo: " + weiTingRoadInfo.getAdCode());}/*** 清除无效缓存*/private void deleteWeiTingInvalidData() {List<WeiTingTable> all = LitePal.findAll(WeiTingTable.class);int count = 0;for (WeiTingTable weiTingTable : all) {if (TextUtils.isEmpty(weiTingTable.getMidPicPath())) {weiTingTable.delete();++count;}}Log.e(TAG, "count: " + count);}
}

不清楚地方可留言，有时间回复。

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