支持简单的字符串插值

Author: lvan100

spring-properties-default.go

@@ -271,15 +271,42 @@ func bindStructField(p Properties, v reflect.Value, str string, opt bindOption)
 	bindValue(p, v, key, def, opt)
 }
 
+// Interpolate 处理字符串插值
+func Interpolate(p Properties, str string) string {
+
+	start := strings.Index(str, "${")
+	if start < 0 {
+		return str
+	}
+
+	end := strings.IndexByte(str[start+2:], '}')
+	if end < 0 {
+		return str
+	}
+
+	end = start + 2 + end
+	key := str[start+2 : end]
+	val, ok := p.GetDefaultProperty(key, nil)
+	if !ok {
+		panic(fmt.Errorf("property \"%s\" not config", key))
+	}
+
+	return str[:start] + fmt.Sprint(val) + Interpolate(p, str[end+1:])
+}
+
 // resolveProperty 解析属性值，查看其是否具有引用关系
 func resolveProperty(p Properties, _ string, value interface{}) interface{} {
-	str, ok := value.(string)
 
-	// 不是字符串或者没有使用配置引用语法
-	if !ok || !strings.HasPrefix(str, "${") {
+	str, ok := value.(string)
+	if !ok {
 		return value
 	}
 
+	// 遍历字符串看看是否包含 ${} 结构并解析
+	if !strings.HasPrefix(str, "${") {
+		return Interpolate(p, str)
+	}
+
 	key, def := parsePropertyTag(str[2 : len(str)-1])
 	if val, _ := p.GetDefaultProperty(key, def); val != nil {
 		return resolveProperty(p, key, val)

spring-properties-default_test.go

@@ -807,3 +807,18 @@ func TestDefaultProperties_KeyCanBeEmpty(t *testing.T) {
 	p.BindProperty("", &s)
 	assert.Equal(t, s.KeyIsEmpty, "kie")
 }
+
+func TestInterpolate(t *testing.T) {
+	p := SpringCore.NewDefaultProperties()
+	p.SetProperty("name", "Jim")
+	str := SpringCore.Interpolate(p, "my name is ${name")
+	assert.Equal(t, str, "my name is ${name")
+	str = SpringCore.Interpolate(p, "my name is ${name}")
+	assert.Equal(t, str, "my name is Jim")
+	str = SpringCore.Interpolate(p, "my name is ${name}${name}")
+	assert.Equal(t, str, "my name is JimJim")
+	str = SpringCore.Interpolate(p, "my name is ${name} my name is ${name")
+	assert.Equal(t, str, "my name is Jim my name is ${name")
+	str = SpringCore.Interpolate(p, "my name is ${name} my name is ${name}")
+	assert.Equal(t, str, "my name is Jim my name is Jim")
+}