eclipse DBUtils 报错问题——请大神解答，感激涕零

显示全部楼层 · 2021-1-27 06:49:20

publicstaticfinalStringurl="jdbc:oracle:thin:@127.0.0.1:1521:XE";
publicstaticfinalStringdriver_name="oracle.jdbc.driver.OracleDriver";
publicstaticfinalStringuser="system";
publicstaticfinalStringpassword="xxkxxk11";
publicstaticConnectiongetConnection(){
Connectionconnection=null;
try{
Class.forName(driver_name);
System.out.println("获取数据库名称");
}catch(ClassNotFoundExceptione){
e.printStackTrace();
}
try{
connection=DriverManager.getConnection(url,user,password);
System.out.println("打开数据库成功");
}catch(SQLExceptione){
//TODOAuto-generatedcatchblock
e.printStackTrace();
}
returnconnection;
}

@Test
publicvoidtest(){
try{
QueryRunnerrunner=null;
Stringsql="selectid,namefromsystem.STU";
System.out.println("查询语句："+sql);
Object[]rs=runner.query(DBUtils.getConnection(),sql,newArrayHandler());
System.out.println("ArrayHandler:"+Arrays.toString(rs));
}catch(Exceptione){
e.printStackTrace();
}
}
运行报错如下：
获取数据库名称
打开数据库成功
java.lang.NullPointerException
atstudyDButils.testTest.test(testTest.java:25)
atsun.reflect.NativeMethodAccessorImpl.invoke0(NativeMethod)
atsun.reflect.NativeMethodAccessorImpl.invoke(UnknownSource)
atsun.reflect.DelegatingMethodAccessorImpl.invoke(UnknownSource)
atjava.lang.reflect.Method.invoke(UnknownSource)
atorg.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
atorg.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
atorg.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
atorg.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
atorg.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
atorg.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
atorg.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
atorg.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
atorg.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
atorg.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
atorg.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
atorg.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
atorg.junit.runners.ParentRunner.run(ParentRunner.java:363)

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千问 · 2021-1-27 06:49:20

知道原因了，对象没有初始化!

QueryRunnerrunner=newQueryRunner();