Saving_
2017-05-10 17:48
java.lang.NullPointerException
at com.imooc.hanxiu.JDBCutils.JDBCUtil.getConnection(JDBCUtil.java:33)
at test.java.com.imooc.hanxiu.testApp.testConnection(testApp.java:19)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:45)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:42)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:263)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:68)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:47)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:231)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:60)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:229)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:50)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:222)
at org.junit.runners.ParentRunner.run(ParentRunner.java:300)
at org.junit.runner.JUnitCore.run(JUnitCore.java:157)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:51)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
我的代码如下 public static Connection getConnection() throws Exception {
/**
* 不建议大家把配置硬编码到代码中
*
* 最佳实践:配置性的建议写到配置文件中
*/
// String url = "jdbc:mysql:///springdata";
// String user = "root";
// String password = "123";
// String driverClass = "com.mysql.jdbc.Driver";
String classpath = Thread.currentThread().getContextClassLoader().getResource("/").getPath();
String fileName = classpath + "db.properties";
System.out.print(fileName);
FileInputStream fis = new FileInputStream(fileName);
Properties properties = new Properties();
properties.load(fis);
// 错误的文件引入待解决
String url = properties.getProperty("jdbc.url");
String user = properties.getProperty("jdbc.user");
String password = properties.getProperty("jdbc.password");
String driverClass = properties.getProperty("jdbc.driverClass");
Class.forName(driverClass);
Connection connection = DriverManager.getConnection(url, user, password);
return connection;
}
可以将代码改成
```
public static Connection getConnection() throws IOException, SQLException, ClassNotFoundException {
InputStream is = JDBCUtil.class.getResourceAsStream("/db.properties");
Properties properties = new Properties();
properties.load(is);
String url = properties.getProperty("jdbc.url");
String driver = properties.getProperty("jdbc.driver");
String user = properties.getProperty("jdbc.user");
String password = properties.getProperty("jdbc.password");
Class.forName(driver);
Connection connection = DriverManager.getConnection(url, user, password);
return connection;
}
```
主要注意第一行的修改
```
InputStream is = JDBCUtil.class.getResourceAsStream("/db.properties");
```
一样的问题
如果运行在Windows下,property 的加载不要用getResource而是直接用new File. 好像Windows下不支持这种classpath的搜索。在Linux和Unix上都不会有问题。
轻松愉快之玩转SpringData
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