实体类中如何进行数据库表中的关联。GreenDao实现的很简单。
一对一，使用注解@ToOne（），括号中参数为对应表对应的外键
public class Son {
@Id(autoincrement = true)
private Long id;
private String name;
private int age;
pr...
greendao3.0以上使用步骤（一）：基础使用greendao3.0以上使用步骤（二）：数据库到底该怎么升级
引入数据库
1、在项目的build.gradle中加入这些配置// Top-level build file where you can add configuration options common to all sub-projects/modules.buildscript {
这个是代码混淆的<em>问题</em>，到时Greendao找不到这个类，所以需要在proguard-rules加上-keep class org.greenrobot.greendao.**{*;}
-keepclassmembers class * extends org.greenrobot.greendao.AbstractDao {
public static java.lang.String TABLEN
String sql="select PAYMENT_PAY_BY,sum(PAYMENT_MONEY) from PAYMENT where SYSTEM_BOOK_CODE = ? " +
"and BRANCH_NUM= ? and SHIFT_TABLE_NUM=? and SHIFT_TABLE_BIZDAY=? ...
代码混淆后GreenDao 报错:Could not init DAOConfig
项目使用greendao打包混淆的时候，安装成功之后启动崩溃，查看log显示 Could not init DAOConfig，这个是混淆产生的<em>问题</em>，在网上查看解决方法需要加入混淆配置
-keep class org.greenrobot.greendao.**{*;}
-keepclassmembers clas...
sql="select '实收金额' name,round((SELECT round(sum(cast(tx_cash_amount as decimal(18,2))),2) from TRANSINFO t where t.cash_time>1584120232" and t.cash_time < 1595124124 " and t.status in(0,4)),2) value";
Cursor c = db.rawQuery(sql, null);
<em>问题</em>如下：当在<em>Android</em>中使用<em>greenDao</em>调用原生sql求某几条记录之和时，所求和字段是real类型的，,五位及以上的小数和，所求和的小数位失真，自动被抹零了。不知道哪位<em>大神</em>可以回答一下我出现的<em>问题</em>？小弟感激不尽了！！！
关于android数据库框架，有很多种，各有各的优势。
先来看一个图
，但对于批量查询操作，性能最优的莫过于greendao了。今天来说说关于它简单的使用方式。
配置gradle
dependencies {
// This is only needed if you want to use encrypted databases
// compile 'net.zetetic:
Caused by: java.lang.IllegalArgumentException: No view found for id 0x7f060000
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
...
在使用<em>greenDao</em>根据条件查询数据的时候碰到<em>问题</em>，现在记录一下。
调用的方法是Dao对象调用queryRaw(String where, String... selectionArg);返回的是一个List。
/** A raw-style query where you can pass any WHERE clause and arguments. */
public Lis
android 本地数据库报错unknown error (Sqlite code 14): Could not open database, (OS error - 2:No such file or directory)....的根本原因是用了大于２３的ＳＤＫ构建，两种解决方案
一、用低于２３的ＳＤＫ版本构建
二、动态添加权限
public static final int REQUE...
添加依赖 // This is only needed if you want to use encrypted databases
compile 'net.zetetic:android-database-sqlcipher:3.5.6'连接加密数据库 mHelper = new MySQLiteOpenHelper(this, "test2-db", null);
// db = ...
使用GreenDao数据库，混淆发布后运行出现 Could not init DAOConfig项目混淆日志报错，Could not init DAOConfig解决：在proguard-rules.pro中加入-keepclassmembers class * extends de.greenrobot.dao.AbstractDao {
public static java.lan...
在greendao使用的时候大家可能都会<em>遇到</em>过版本兼容<em>问题</em>，就是我们在使用GreenDao数据库的时候会发现，在android5.0以上的系统版本，没什么<em>问题</em>，我们可以正常运行，这也没<em>问题</em>，但是在android5.0一下版本就会报错。java.lang.NoClassDefFoundError: org.greenrobot.greendao.database.StandardDatabase
at
依赖
public class Glideload extends AppGlideModule {
@Override
public void applyOptions(@NonNull Context context, @NonNull GlideBuilder builder) {
int shu = 1024102424;
builder.setMemoryCache(new LruRes...
通过断点，和控制台输出确定就是new对象的时候，出现报错。百度说是因为没有无参构造器，并不是这个<em>问题</em>。
```
2019-01-24 11:05:18,590 ERROR [500.jsp] - Handler dispatch failed; nested exception is java.lang.NoSuchMethodError: com.pt.common.utils.excel.ExportExcel: method ()V not found
org.springframework.web.util.NestedServletException: Handler dispatch failed; nested exception is java.lang.NoSuchMethodError: com.pt.common.utils.excel.ExportExcel: method ()V not found
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:978)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:897)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:970)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:861)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:624)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:846)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:731)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at com.opensymphony.sitemesh.webapp.SiteMeshFilter.obtainContent(SiteMeshFilter.java:129)
at com.opensymphony.sitemesh.webapp.SiteMeshFilter.doFilter(SiteMeshFilter.java:77)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:61)
at org.apache.shiro.web.servlet.AdviceFilter.executeChain(AdviceFilter.java:108)
at org.apache.shiro.web.servlet.AdviceFilter.doFilterInternal(AdviceFilter.java:137)
at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
at org.apache.shiro.web.servlet.ProxiedFilterChain.doFilter(ProxiedFilterChain.java:66)
at org.apache.shiro.web.servlet.AbstractShiroFilter.executeChain(AbstractShiroFilter.java:449)
at org.apache.shiro.web.servlet.AbstractShiroFilter$1.call(AbstractShiroFilter.java:365)
at org.apache.shiro.subject.support.SubjectCallable.doCall(SubjectCallable.java:90)
at org.apache.shiro.subject.support.SubjectCallable.call(SubjectCallable.java:83)
at org.apache.shiro.subject.support.DelegatingSubject.execute(DelegatingSubject.java:387)
at org.apache.shiro.web.servlet.AbstractShiroFilter.doFilterInternal(AbstractShiroFilter.java:362)
at org.apache.shiro.web.servlet.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:125)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:262)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:197)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:219)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:110)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:506)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:169)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:962)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:445)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1115)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:637)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:722)
Caused by: java.lang.NoSuchMethodError: com.pt.common.utils.excel.ExportExcel: method ()V not found
at com.pt.modules.mds.mdsquota.web.MdsQuotaDetailController.getFileTemplate(MdsQuotaDetailController.java:268)
at com.pt.modules.mds.mdsquota.web.MdsQuotaDetailController$$FastClassBySpringCGLIB$$db56097f.invoke()
at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204)
at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:721)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157)
at org.apache.shiro.spring.security.interceptor.AopAllianceAnnotationsAuthorizingMethodInterceptor$1.proceed(AopAllianceAnnotationsAuthorizingMethodInterceptor.java:82)
at org.apache.shiro.authz.aop.AuthorizingMethodInterceptor.invoke(AuthorizingMethodInterceptor.java:39)
at org.apache.shiro.spring.security.interceptor.AopAllianceAnnotationsAuthorizingMethodInterceptor.invoke(AopAllianceAnnotationsAuthorizingMethodInterceptor.java:115)
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179)
at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:656)
at com.pt.modules.mds.mdsquota.web.MdsQuotaDetailController$$EnhancerBySpringCGLIB$$c06e47.getFileTemplate()
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:220)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:134)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:116)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:827)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:738)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:963)
... 50 more
```
代码如下: public class DaoConfig { public static DaoManager getDaoManagerInstance() { DaoManager daoManager = null; try { String resource ="com/jxgl/persistence/sqlmapdao/config/dao.xml"; Rea
