java - 获取 java.lang.NoSuchMethodException : Property 'xx' has no setter method in class 'class xx' while using PropertyUtils. setSimpleProperty 函数

Question

我正在使用 PropertyUtils.setSimpleProperty 动态调用我的 setter 方法，但由于某种原因，我不断出错。需要您的帮助来找出根本原因。这是我的代码:

class FileDt {
    String reportName=null;
    String reportLocation=null;

    public String getReportName() {
        return reportName;
    }
    public void setReportName(String reportName) {
        this.reportName = reportName;
    }
    public String getReportLocation() {
        return reportLocation;
    }
    public void setReportLocation(String reportLocation) {
        this.reportLocation = reportLocation;
    }
}

class Foo {
    public static void main (String... args) {
        FileDt dt = newFileDt();
        // #1
        PropertyUtilsBean.setSimpleProperty(dt, "reportName", "abc.html");
        // #2
        PropertyUtilsBean.setSimpleProperty(dt, "reportLocation", "c://");
    }
}

这两个方法都抛出异常

1. Caused by: java.lang.NoSuchMethodException: Property 'reportName' has no setter method in class 'class FileDt' at org.apache.commons.beanutils.PropertyUtilsBean.setSimpleProperty(PropertyUtilsBean.java:2096)

2. Caused by: java.lang.NoSuchMethodException: Property 'reportLocation' has no setter method in class 'class FileDt' at org.apache.commons.beanutils.PropertyUtilsBean.setSimpleProperty(PropertyUtilsBean.java:2096)

Answer 1

PropertyUtilsBean.setSimpleProperty(Object bean, String name, Object value))仅适用于公共(public)方法。看起来您的类使用包范围(类定义中缺少 public 关键字)。

运行以下示例:

import org.apache.commons.beanutils.PropertyUtils;

import java.lang.reflect.InvocationTargetException;

class FileDt {
    String reportName;
    String reportLocation;

    public String getReportName() {
        return reportName;
    }

    public void setReportName(String reportName) {
        this.reportName = reportName;
    }

    public String getReportLocation() {
        return reportLocation;
    }

    public void setReportLocation(String reportLocation) {
        this.reportLocation = reportLocation;
    }

    public static void main(String[] args) throws IllegalAccessException, NoSuchMethodException, InvocationTargetException {
        FileDt dt = new FileDt();
        // #1
        PropertyUtils.setSimpleProperty(dt, "reportName", "abc.html");
        // #2
        PropertyUtils.setSimpleProperty(dt, "reportLocation", "c://");
    }
}

抛出您描述的异常:

Exception in thread "main" java.lang.NoSuchMethodException: Property 'reportName' has no setter method in class 'class FileDt'
    at org.apache.commons.beanutils.PropertyUtilsBean.setSimpleProperty(PropertyUtilsBean.java:2096)
    at org.apache.commons.beanutils.PropertyUtils.setSimpleProperty(PropertyUtils.java:928)
    at FileDt.main(FileDt.java:28)

让你的类(class)public解决了这个问题:

import org.apache.commons.beanutils.PropertyUtils;

import java.lang.reflect.InvocationTargetException;

public class FileDt {
    String reportName;
    String reportLocation;

    public String getReportName() {
        return reportName;
    }

    public void setReportName(String reportName) {
        this.reportName = reportName;
    }

    public String getReportLocation() {
        return reportLocation;
    }

    public void setReportLocation(String reportLocation) {
        this.reportLocation = reportLocation;
    }

    public static void main(String[] args) throws IllegalAccessException, NoSuchMethodException, InvocationTargetException {
        FileDt dt = new FileDt();
        // #1
        PropertyUtils.setSimpleProperty(dt, "reportName", "abc.html");
        // #2
        PropertyUtils.setSimpleProperty(dt, "reportLocation", "c://");
    }
}