需求说明：需要对一个service接口进行单元测试

1.在pom.xml中加入依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.0.0.RELEASE</version>
        <relativePath/> <!-- lookup parent from repository -->
    </parent>

    <groupId>org.example</groupId>
    <artifactId>springboot-interview-demo</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

        <!--引入springboot内置的tomact作为启动容器，不然启动后会自动关闭-->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <!-- MySQL驱动 -->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.22</version>
        </dependency>
        <!-- 集成MyBatis -->
        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.1.2</version>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.2.19</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.28</version>
        </dependency>


        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
        </dependency>


        <dependency>
            <groupId>org.powermock</groupId>
            <artifactId>powermock-api-mockito2</artifactId>
            <version>2.0.2</version>
        </dependency>
       <!-- <dependency>
            　　<groupId>org.powermock</groupId>
            　　<artifactId>powermock-module-junit4</artifactId>
            　　<version>2.0.2</version>
        </dependency>-->
        <dependency>
            <groupId>org.powermock</groupId>
            <artifactId>powermock-module-junit4</artifactId>
            <version>2.0.2</version>
            <scope>test</scope>
        </dependency>


    </dependencies>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

</project>

2.编写controller类

@RestController
@RequestMapping("/tx")
public class TxClassController {

//    @Autowired
//    private TxClass txClass;

   // @GetMapping("tx_required")
    public String testTx() throws Exception {
        TxTable txTable=TxTable.getInstance();
        System.out.print("AAAAAAAAAAAAAAAAAA");
        return "success";
    }
}

3.编写实体类

@AllArgsConstructor
@NoArgsConstructor
@Data
@Entity(name = "oct_tx")
public class TxTable {

    private static TxTable txTable= new TxTable();

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private Integer id;

    @Column(name="name")
    private String name;

    public static TxTable getInstance(){
        return txTable;
    }
}

4.编写测试类

@RunWith(PowerMockRunner.class)
@PrepareForTest({TxClassController.class,TxTable.class})
public class TxClassControllerTest {

    @InjectMocks
    private TxClassController txClassController;

    @Mock
    private TxClass txClass;

    @Test
    public void test() throws Exception {
        PowerMockito.mockStatic(TxTable.class);
        TxTable txTableMock=PowerMockito.mock(TxTable.class);
        PowerMockito.when(TxTable.getInstance()).thenReturn(txTableMock);
        txClassController.testTx();
    }
}

测试结果：

出现这个说明已经模拟对象成功